Forums/Z31P/z31-performance-upgrade-forums engine-mechanical-aa/VG33E head gasket failures and head warp
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spddm0n: (2017-01-25 21:29:35)
Hey all -
I'm new to this forum. [archived image: smile.png] I have a handful (literally) of Nissan Xterras that all have head gasket failures. This has been a known issue for many years (as I research it), but the engineer in me needs to find a solution, or perhaps even the root cause. [archived image: smile.png]
After my research finally turned up the MLS HG from ASCO, and no other known MLS HG known to VG33E users anywhere (Xterra, Frontier, otherwise), I was excited to learn of this community using the OWO heads from the VG33E. I'm hoping someone might be able to shed some light the issue I have with the heads themselves, and see how you guys are handling it.
VG33E users have been experiencing HG failures for a long time. Many of these failures occur within the first 120,000 miles of a stock, never-been-opened engine. Nissan Corporate has no explanation of, or desire to address, this issue. [archived image: smile.png] Additionally, many owners experience repeat failures. I've seen posts from people having repeat failures, and even a few with three. It's hard to tell at this point (I did just start an official blown-HG registry on clubxterra.org) what is causing the repeat failures; it's likely an improper repair procedure is at the root, but we don't know yet.
I know this is more of a performance modification for you all to use the VG33E (OWO), and you probably drive your cherished vehicles a lot less than Xterra/Frontier owners (daily drivers and hundreds of thousands of miles), but I'm curious about whether or not you experience the same issue with the OWO heads.
So far, every set of heads I've removed require milling. Most beyond the .008" limit Nissan publishes in their FSM (this would also include any milling to the block). I did, however, just pull apart a JDM VG33E from an Nissan Elgrand, that was expected to have the average 50K-65K miles, that only required .005", but that is not the norm. The last set I pulled from a motor with 150,000 miles required .010".
Are you guys milling heads that far? Are you using and shims to make up the difference? I assume you aren't using a thicker head gasket, since I don't think there are any (yet). All the basic repair-level gasket makers are mimicking the OEM (.048" manufactured with 6% crush rate to about .045").
Does this affect your valve and ignition timing enough to worry about it? I can't imagine the compression level changes that much, but I plan to calculate it to know for sure. I'm still trying to located piston head volume and measure the combustion chamber volume in the head to be certain what is happening.
Ultimately, I'm trying to figure out the best practice I can find to best ensure a long running time on these head gaskets for Xterra and Frontier guys. I'm buying a lot of them in the used market and restoring them for resale, but I'm concerned about the gaskets. I would like to think this could be addressed and an expectation could be achieved for owners to get 200K+ miles on a head gasket. Is that achievable?
I've also considered some better head bolts, but ARP doesn't make a set…though I think I could put them together from the set you guys are using with your VG30 blocks. Having said that, theyh may not be affordable. I could probably afford to use a MLS HG, if I thought that would fix the issue, but we aren't boosted (for the most part), and added cost for block surface prep (from a machine shop) may make this expensive too. [archived image: smile.png]
Any thoughts?
Thanks for any insight you can offer. [archived image: smile.png]
Thanks!
Timbo_021: (2017-01-26 08:49:43)
Pretty unheard of here I think. In my opinion, if the heads are warping then they are getting hot. It's not a poor cooling system design is it?
spddm0n: (2017-01-26 17:16:14)
Pretty unheard of here I think. In my opinion, if the heads are warping then they are getting hot. It's not a poor cooling system design is it?
Ok, yeah I searched this site a bit and didn't see much for complaining about these issues. [archived image: smile.png]
A poor cooling design issue could be very possible. That certainly speaks to the failures being over a longer period of time (compared to blow-outs from high internal combustion pressures). If so, what are you guys doing different with the heads? I'm collecting data still, but it's possible cooling issues could be possible if the failures are occurring in the same place often.
The failure I have is in the back behind cylinder number #6 (on the south side of the cylinder bore). It disrupted the fire ring.
spddm0n: (2017-01-26 17:26:39)
Where are you guys typically getting your OWO heads? Also, are you measuring them to know if they've been milled? Perhaps I can just find them from another model that doesn't get so hot. The JDM heads I just purchased were better, requiring only .005", but were complete with the engine. I may need another head source. [archived image: smile.png]
I'll measure the combustion chamber volume today and see what I come up with. I'll also pull a piston and measure the volume of the head to get an idea of the total chamber volume.
Timbo_021: (2017-01-26 23:03:42)
Are there any marks from detonation on the piston? I actually had a blow out a while ago but this was because the engine ran lean and detonated down the 1/4 mile. Was at the rear on no.5 cylinder. But Yeah, as far as I know nobody hear goes into that much depth when they need to machine their heads. I just skimmed mine and put new gaskets on (did both banks anyway) and away I went, good as new.
My heads came from a Pathfinder VG33, early 2000's and the block is also Pathfinder but running VG30 crank. I believe most blokes use Pathfinder stuff on here too, not so much Xterra/Frontier.
spddm0n: (2017-02-07 18:10:06)
Are there any marks from detonation on the piston? I actually had a blow out a while ago but this was because the engine ran lean and detonated down the 1/4 mile. Was at the rear on no.5 cylinder. But Yeah, as far as I know nobody hear goes into that much depth when they need to machine their heads. I just skimmed mine and put new gaskets on (did both banks anyway) and away I went, good as new.
My heads came from a Pathfinder VG33, early 2000's and the block is also Pathfinder but running VG30 crank. I believe most blokes use Pathfinder stuff on here too, not so much Xterra/Frontier.
Sorry for the delay, I thought I replied to this. [archived image: smile.png]
No evidence of detonation. As it turns out, both gaskets showed damage (I didn't think to look at the passenger side before, since the compression test didn't show much of a reduction to indicate an issue). They showed damage in the very same place (cylinder #1 on the passenger side since the passenger side head is mirrored from the driver side).
How did you "skim" the heads? The machine shop here had to go a full .010" to get the old gasket material off and make the head flat. I'm thinking that could be a part of the long term failures we are seeing. The heads are warped once removed. I did take in a second set of heads from a low mileage JDM engine I broke down to change the gaskets on. It only required .005" to get them flat. I'm not certain if this is due to the "lower mileage" condition of the engine, or that I removed the head bolts in about 15 degree increments, rather than 90 degrees (as called for my the FSM).
I know these engines (in the Xterra and Frontier) are failing early and often, BEFORE, the engines are ever opened, so I imagine there is a larger global issue, but it's hard to determine if this is due to heads warping. They are "warped" once removed, and removed as carefully as possible, but it's hard to say if they are warped before removal (I would guess they are), or the damage occurs during removal.
I have two more sets of heads (installed) on two more engines. One set if from a 97K mile USDM engine that through a rod. The second set in on a motor with 200K+ miles with a thrown rod (see a pattern developing here). I'll remove both sets of heads, removing the bolts in 15 degree increments, and see what each set requires to get flat (assuming they are visually in good shape otherwise, since it costs $100 a set to have milled, and the amount to be milled cannot be determined until it's actually performed). I imagine the damage is typically done with poor cooling on these vehicles. The cooling systems must not be well designed and causing premature failure to the head gaskets (which is likely the cause of the thrown rods on many of these engines, since coolant mixes with the oil and people still drive them around with coolant in the rod and main bearings).
Augustus Maximus: (2017-02-08 13:01:24)
Most of us run the upgraded 3 core radiator and when we blow HG is almost always from detonation, not over heating. Some of us including myself are into custom forged pistons with higher than stock compression ratios.
spddm0n: (2017-02-08 19:52:41)
Most of us run the upgraded 3 core radiator and when we blow HG is almost always from detonation, not over heating. Some of us including myself are into custom forged pistons with higher than stock compression ratios.
Yeah, I figured most of you guys using the VG33E for performance reasons, don't really put the same kind of miles on this engine as a daily driver Xterra or Frontier. [archived image: smile.png]. Also, I'm suspecting the entire cooking system in the Xterra/Frontiree is simply inadequate. Do you guys log coolant temp and pressure? I do this on my performance MR2 builds, but never bothered on a daily driver. I wonder if the issue could simply be due to longe term coolant temps being elevated.
Augustus Maximus: (2017-02-08 20:07:22)
My VG33e came out of a 1999 Quest that my father daily drove until a few months before he passed. No issues then or now with 120k on it. I will disassemble for the sole reason of forging the internals for big power. The 0W0 head is no different from our W series except for 10mm exhaust studs and so called smoother casting in some places
spddm0n: (2017-02-08 20:42:04)
Interesting…did you mill the heads on the VG33 after you pulled it? I haven't looked at the Quest in person, or did much research and investigation, but I wonder if they had regular failures too. Most Xterra/Frontier occur between 120K and 180K.
88sinZ: (2017-02-10 01:52:17)
There's no reason blowing a head gasket it common, because its not - with proper setup method and maintenance. I've spun up a VG33ER and boosted a VG33ET to 330/390 @14lbs
Something in your method or maintenance is incorrect. Don't blame the engine for your failures.
spddm0n: (2017-02-10 16:56:27)
There's no reason blowing a head gasket it common, because its not - with proper setup method and maintenance. I've spun up a VG33ER and boosted a VG33ET to 330/390 @14lbs
Something in your method or maintenance is incorrect. Don't blame the engine for your failures.
I'm trying to determine the problem, not place blame. I'm trying to help solve the issue WHY this occurs. None of these engines are mine, they are fellow forum enthusiasts and daily drivers of Xterra/Frontier. These owners are experiencing HG failures as early as 30,000 miles, 40,000 miles, 80,000 miles, but most commonly around 120,000. A high percentage of owners with as many as 180,000 miles on their engines have had a head gasket fail twice, and even three times. Unless you have your head in the sand, you would have to see a pattern emerging here. [archived image: smile.png] Check out this link to some of the data I'm referring to: http://www.carcomplaints.com/Nissan/…d_gasket.shtml
There could be a maintenance issue here, but it's hard to determine. A lot of the first time failures are possibly due to improper maintenance, but if this is true, this motor is a high maintenance application in the Xterra/Frontier. HG's should simply not fail at 40,000 miles (could be an isolated incident, but still…). Does Nissan suggest changing the coolant before 40,000? Is it so sensitive that if you drove over 50,000 miles on it, you would blow a HG? [archived image: smile.png] Wow, ok…I'm just gonna say it…Nissan is NOT Toyota. [archived image: smile.png]
Other common lack of maintenance would be oil maintenance, right? I don't imaging a HG would be the typical failure if you didn't change the oil for 40,000 miles; more likely a spun bearing. I do see a regular failure of bottom ends too; mostly spun bearings. I have a suspicion HG's may have small (tears) failures, some of which owners probably don't even know they've failed. They do not have the signs of full-blown HG failure, other than cooling (overheating) issues. This leads to higher operating temps, reoccurring overheating issues, and ultimately full blown HG failure. During this process, oil is circulating with small amounts of coolant in it, causing lubrication issues in the bearings. People I've bought vehicles from admit to driving the vehicle several times and over several miles, with the full-blown failure. This could cause coolant to mix with oil in the bearings, and could reasonably cause damage to the bearings that a "repair" shop will never identify, because their job is simply to change the HG.
The whole point here is to help identify the problem. Admitting there is a problem is the first step. [archived image: smile.png] [archived image: smile.png]
88sinZ: (2017-02-11 07:34:14)
don't take it personal, im goin from a purely QA mech stand pont. The VG engine series is 1983 tech, if mech isn't followed it fails - but there's quite a bit of room for error here.
oil changes have nothing to due with mechanical failure until HIGHLY neglected.
I have over heated a VG33ER 2 times one crawling the beach, and one in +100F temp stand still traffic, only to pull over and water it down. Still pushing 140K on that engine. No coolant should be present in the oil - thats a major failure.
I come from the aviation field, where any failure/corrosion/compromise is not acceptable - i apply this philosophy to my vehicles and it works 100%. Lets face it these vehicles are pushing 30yrs old, they need component and hardware replacements along with seal and surface inspection.
260DET: (2017-02-13 08:56:23)
If the failures are common in one particular Nissan model then it could be that the cooling system is not operating 100%. Coolant may not be flowing completely at the front of the heads due to the radiator/header tank being too low, I notice on the LS3 engine that it has small bleed lines at the front of each head, Holden Commodores with the RB30 engine used to have head failures due to the radiator being too low.
spddm0n: (2017-02-14 13:36:56)
don't take it personal, im goin from a purely QA mech stand pont. The VG engine series is 1983 tech, if mech isn't followed it fails - but there's quite a bit of room for error here.
oil changes have nothing to due with mechanical failure until HIGHLY neglected.
I have over heated a VG33ER 2 times one crawling the beach, and one in +100F temp stand still traffic, only to pull over and water it down. Still pushing 140K on that engine. No coolant should be present in the oil - thats a major failure.
I come from the aviation field, where any failure/corrosion/compromise is not acceptable - i apply this philosophy to my vehicles and it works 100%. Lets face it these vehicles are pushing 30yrs old, they need component and hardware replacements along with seal and surface inspection.
Poor oil maintenance is not likely the issue with HG failure, but is quite another issue. Oil drain-back appears to be an issue, so poor maintenance could be more consequential than we think and could be leading to premature wear on the bearings. I'll soon pull the engines that failed on the bottom ends too, to see what I can see. One of them through a rod through the block. Another engine just has severe rod knock, so possibly just a spun bearing.
Regarding the HG's though, I think the issue is likely more likely caused by poor cooling. Keep you fingers crossed on 140K miles. [archived image: smile.png] I'm a mechanical engineer by education, so I share the failure/compromise curse with you. I've not yet been impressed with Nissan technology, when compared to Toyota. Just the lack of attention to the block casting saddens me. [archived image: smile.png] Of course, I'm making all my comparisons to the 3SGTE Toyota engine that is fairly bulletproof (a lot of us making 500 whp with no more than piston upgrades; some even tuned enough to make 500 reliably on stock cast pistons).
spddm0n: (2017-02-14 13:47:22)
If the failures are common in one particular Nissan model then it could be that the cooling system is not operating 100%. Coolant may not be flowing completely at the front of the heads due to the radiator/header tank being too low, I notice on the LS3 engine that it has small bleed lines at the front of each head, Holden Commodores with the RB30 engine used to have head failures due to the radiator being too low.
Yeah, I ran across this article on the VG30DETT engine that calls out major casting issues with that block, causing overheating of the rear cylinders (this is where I see the HG's failing). http://www.motoiq.com/MagazineArticl…TT-part-1.aspx
There are a couple cool photos of the coolant passages being blocked from the factory, and what they look like once the block is ported. I didn't look that closely at my blocks. I'll take a look at them today. I wonder if they have the same issue as the VG30 block.
NissanEgg: (2017-02-16 01:44:18)
As a master tech at a Nissan dealership, the biggest issues I see that left unrepaired causing head gasket failure on the VG33 are;
-corroded and leaking thermostat bypass hose
-corroded and leaking lower plenum gaskets
-stuck closed thermostat
-ruptured radiator top section (plastic part)
-cracked exhaust manifolds which lead to restricted catalytic converters
Other ares of common coolant leakage are the thermo-element below the throttle body, sealing surface between the lower plenum and upper coolant outlet neck, and the heater hose/pipe connections.
You will be surprised at the number of people who ignore perceived "minor" coolant leaks because the temperature gauge never reads hot. Truth is the coolant temp sending unit is located near the highest point in the cooling system, and when a small loss of coolant happens it causes the sending unit to not come in contact with coolant. With no proper contact with coolant the sending unit sends erroneous readings often indicating normal temps.
88sinZ: (2017-02-16 06:56:09)
Oil drain-back appears to be an issue, so poor maintenance could be more consequential than we think and could be leading to premature wear on the bearings.
not yet been impressed with Nissan technology, when compared to Toyota.
Oiling issue aside, there should be no issue with lubrication outside of extreme circumstances.
and i agree 'Yotas have a tech edge on Nissans - but as for tried and true Nissan is the Ford of Japan, they just work not as efficient or powerful but they chug along
As a master tech at a Nissan dealership, the biggest issues I see that left unrepaired causing head gasket failure on the VG33 are;
-corroded…
-corroded…
proof is in the pudding, these engines mate anode and cathode metals, corrosion is a major peeve here. I've flushed the system twice from 60k and 90K, will likely do another this summer - favoring on a 70/30
and yeah, i snapped that shitty little nipple on the upper cap.. shitty design, the epoxy is holding up so far
passenger manifold #1 cracked cats clogged to shit, dropped in doug thorley headers and air gap pipes
spddm0n: (2017-02-16 17:53:41)
As a master tech at a Nissan dealership, the biggest issues I see that left unrepaired causing head gasket failure on the VG33 are;
-corroded and leaking thermostat bypass hose
-corroded and leaking lower plenum gaskets
-stuck closed thermostat
-ruptured radiator top section (plastic part)
-cracked exhaust manifolds which lead to restricted catalytic converters
Other ares of common coolant leakage are the thermo-element below the throttle body, sealing surface between the lower plenum and upper coolant outlet neck, and the heater hose/pipe connections.
You will be surprised at the number of people who ignore perceived "minor" coolant leaks because the temperature gauge never reads hot. Truth is the coolant temp sending unit is located near the highest point in the cooling system, and when a small loss of coolant happens it causes the sending unit to not come in contact with coolant. With no proper contact with coolant the sending unit sends erroneous readings often indicating normal temps.
Wow, interesting perspective…
In your experience, how do those smaller coolant leaks point toward evidence of the HG failure issue? Do you mean the small coolant leaks are enough to disrupt the coolant flow in the system, even while under pressure, enough to "miss" the coolant temp sensor? Wow. That's bad design. [archived image: smile.png]
My shop truck (old 88 Toyota pickup with that pesky little troublesome V6), leaks coolant and oil out of it so much, it requires a weekly refill, AND it has a known design flaw in the HG area (that Toyota addressed properly and actually "resolved" it in the recall), but that engine doesn't seem to have the same re-occurrence issue as the Nissan VG family of engines.
spddm0n: (2017-02-16 18:08:40)
Oiling issue aside, there should be no issue with lubrication outside of extreme circumstances.
and i agree 'Yotas have a tech edge on Nissans - but as for tried and true Nissan is the Ford of Japan, they just work not as efficient or powerful but they chug along
proof is in the pudding, these engines mate anode and cathode metals, corrosion is a major peeve here. I've flushed the system twice from 60k and 90K, will likely do another this summer - favoring on a 70/30
and yeah, i snapped that shitty little nipple on the upper cap.. shitty design, the epoxy is holding up so far
passenger manifold #1 cracked cats clogged to shit, dropped in doug thorley headers and air gap pipes
Good to know about lubrication. I was hoping to I could resuse my oil pumps, but was starting to worry about all these problems racking up. [archived image: smile.png]
Interesting about your coolant ratio choice. Do you have any indication that this is helping? I'd really like to monitor the coolant temp or the combustion temp in the two rear cylinders (#5, #6). Right now, the best evidence I see, point toward block manufacturing flaws. I looked at two of my VG33E blocks, and both have the same casting flash issue as the VG30 used in the MotoIQ article referenced above. I took the blocks to three machine shops yesterday for opinions…
The first shop, a mostly domestic shop, said that it didn't look "that" bad and wouldn't "worry" about it (this is the same shop that milled by heads .010", further than recommended by Nissan, and told me "not to worry about it". I find that hilarious! They have no experience with a motor after it has left their workbench. [archived image: smile.png]
The second shop, who's owner repaired an Xterra for his daughter recently, after trouble with the HG's, said "You're probably on to something…let's drill that out of there!" I elected not to do it, but would rather practice on one of my blocks with a hole in it already (threw a rod).
The third shop, frowned and agreed that the manufacturers don't care about this kind of issue and suspected it certainly wasn't good. He showed me the tool that he would use to grind it out by hand (like a air die grinder with a 12" long shaft and a bit on the end of it).
It's hard to say, without knowing the exact path of the coolant in the block, but by the looks of it, if coolant is supposed to travel down that center channel all the way to the back of the block, this is likely a contributing factor, if not root cause. It's probably the best mod I could consider doing, to address the issue. So far, nobody has added their HG failure info to my registry thread on clubxterra.com, but all my HG failures, so far, are in cylinders #5 and #6. Coincidence??
NissanEgg: (2017-02-17 01:27:58)
I am talking about the coolant leaks being minor, but over a long period of time. Owners never realized it got hot because the gauge said it was normal. Basically you get air pockets in the heads when coolant gets low and creates extreme hot spots.
I am in the process of replacing head gaskets at work on a 02 Xterra because the lower intake manifold gasket was leaking around the port for number 5 and guy never paid attention until it suddenly started smoking white clouds out of tail pipe. The amount of green dried crusty coolant built up around spark plug #5 and the valley around the knock sensor is insane. That tells me it was a long drawn out leak that went unnoticed.
88sinZ: (2017-02-17 03:09:33)
i'd tell ya throw a head kit on it and see what happens, rockauto has some on wholesale now - join their mailing list and you will receive wholesale notices. Victor Reinz/Beck Arnly is OEM quality so look for them.
Not wanting to get too in detail, keep clean and prep your surfaces.
70/30 coolant is to favor corrosion prevention, and holds temp fine.
Don't trust MotoIQ, they're nothing but a car bro photoing their friends build going on heresy. Let alone, you're comparing a DE to an E. Adding to that the E series has seen major casting series variations, unless they site casting references/serial numbers… take it with a grain of salt,the E series has nearly 5 or more variations..
260DET: (2017-02-17 06:27:14)
Sort of off topic but on Nissan quality, once I got to know both the single and twin cam VG's they were disappointing to me, particularly in design. The crank support could have been a lot better, X bolting would have been justified particularly the turbo's. The single cam's complete intake design restricts power and it's virtually impossible to fix all of it without a complete redesign like was done by Nissan for racing. Funny thing is the RB30, other than the problem previously mentioned, is superior to the VG for general use and has far better breathing potential. It's all about design which does not necessarily cost more.
spddm0n: (2017-02-17 16:11:18)
I am talking about the coolant leaks being minor, but over a long period of time. Owners never realized it got hot because the gauge said it was normal. Basically you get air pockets in the heads when coolant gets low and creates extreme hot spots.
I am in the process of replacing head gaskets at work on a 02 Xterra because the lower intake manifold gasket was leaking around the port for number 5 and guy never paid attention until it suddenly started smoking white clouds out of tail pipe. The amount of green dried crusty coolant built up around spark plug #5 and the valley around the knock sensor is insane. That tells me it was a long drawn out leak that went unnoticed.
Ok, yeah I understand there are leaks, several, and slow, but I guess what I'm getting at is…what about the leaks is direct evidence of the HG failure? I always look at these issues like a murder investigation, and each sign or symptom is a piece of evidence. I would agree the leaks are evidence, but I don't yet see them as a smoking gun. [archived image: smile.png] I will admit, I haven't studied the cooling system entirely, and you could be right, but it just seems to me that you would have to have lost a lot of coolant for the entire system to loose enough pressure to create large enough hot spots to cause failure of the HG's…especially at 40,000 miles. Some of the failures reported are that early.
The defects in the primary water channel of the block, is (so far) the most logical potential source of root cause to me. It would certainly lend credit to the idea the back two cylinders are not getting proper cooling. It might be hard to determine, without adding some temp sensors, but I could imagine the back of the block and heads getting extra toasty without proper flow from the primary channel. Again, I haven't studied the entire water flow design yet, but this block is known to have multiple other issues near the back of the engine. That pesky knock sensor…nobody seems to have solved that problem either. Why does that go bad? [archived image: smile.png] Could be long term heat failure. ??
It seems to me the problem is likely more global that the little water leaks, but I could be wrong. Having said that, the overall cooling design with the manifolds, thermostat and temp sensor location, etc., etc. are almost ridiculous. [archived image: smile.png] I had the two stupid plastic nipple crack on the heater core. What fun that is! [archived image: smile.png]
spddm0n: (2017-02-17 17:23:18)
i'd tell ya throw a head kit on it and see what happens, rockauto has some on wholesale now - join their mailing list and you will receive wholesale notices. Victor Reinz/Beck Arnly is OEM quality so look for them.
Not wanting to get too in detail, keep clean and prep your surfaces.
70/30 coolant is to favor corrosion prevention, and holds temp fine.
Don't trust MotoIQ, they're nothing but a car bro photoing their friends build going on heresy. Let alone, you're comparing a DE to an E. Adding to that the E series has seen major casting series variations, unless they site casting references/serial numbers… take it with a grain of salt,the E series has nearly 5 or more variations..
Uhmmmm..NO. [archived image: smile.png] I don't want to just throw on a head kit on and see what happens. [archived image: smile.png] That's the reason why the problem reoccurs and repeats over and over. This issue requires attention. Attention that Nissan SHOULD have put to it. There is a problem here (and a potential solution), but we must find it.
If I'm going to stick lipstick on a pig, it's going to be pretty… [archived image: smile.png]
1 - HEAD GASKETS: I've already had to over-mill the heads (according to Nissan spec) and I need to consider a solution. I'm talking with ASCO to produce a thicker MLS HG for me, based on the .010" I lost on the head surface. The overall cost of MLS gets sucky, since I may have to surface the decks of the block to meet sealing requirements of the HG manufacturer. I was considering renting a profilometer to measure the stock block surface, to see if it happens to meet the requirements already (Ra <= 50). This is a costly rental too.
There is also an option to use a thin aluminum "shim" offered by Innovative Machine & Supply. They are a minimum of .020" and require Hylomar to seal the shim to the head and block. I've never used a solution like that, so I don't know what level of confidence to expect.
I could be getting super picky now, but my confidence is dwindling and I simply don't want to add to the number of uncertainties already present. [archived image: smile.png] I'm less concerned with overall combustion chamber volume loss, but combine that with spark and valve timing variances and I'm introducing more variables to the outcome. Perhaps I could simply choose an adjustable cam gear to work out the difference in timing due to a reduced thickness of the heads.
2 - BEARINGS: The main and rod bearings are shot in the bottom end, likely because the PO drove the vehicle a few times with coolant in the oil (I removed over 6 quarts of total volume from the oil pan when I drained it (that can't be good on oil pressure). Nissan doesn't sell the bearings anymore, so I have to buy a "one size fits all" set of bearings, and either deal with the bearing clearances being in various levels of the tolerances, OR spend the money and have the crank turned to match the bearings.
3 - HEAD STUDS: ARP head studs (super costly) could be considered, or slightly over-torquing the OEM head bolts a little bit. That's an ugly solution, but it could "add" to the solution if I'm going to stack up band-aids anyway. [archived image: smile.png]
All in all, I think I'm best suited to continue to look at a more global solution, rather than all the band-aids. I can't believe people experience these failures over and over, and the vehicles are sold and bought by new people who continue to throw money into repair shops putting more lipstick on this pig. [archived image: smile.png] I'm into this far enough, I might as well port out the block and give that a go with everything else back to spec. Problem is, I might have to drive it a long time to verify if it have solved the problem. Or, install some custom temp sensors near the two rear cylinders and monitor the temps. I would have to do this on two vehicles though…one that is completely stock, and one with the block ported.
spddm0n: (2017-02-17 17:29:28)
Sort of off topic but on Nissan quality, once I got to know both the single and twin cam VG's they were disappointing to me, particularly in design. The crank support could have been a lot better, X bolting would have been justified particularly the turbo's. The single cam's complete intake design restricts power and it's virtually impossible to fix all of it without a complete redesign like was done by Nissan for racing. Funny thing is the RB30, other than the problem previously mentioned, is superior to the VG for general use and has far better breathing potential. It's all about design which does not necessarily cost more.
I hear ya. I'm a bit surprised too. I've been working with the 3SGTE engine from Toyota for many years, and have just become used to it's excellent design and superior reliability. This is my first V6 engine though, so I'm learning the design requirements for intake manifolds, etc., are much different from the simplicity of the inline cylinder designs. Is there any aftermarket solution for an intake manifold for the VG engines? Upper or lower?
NissanEgg: (2017-02-17 20:25:52)
I think you are over thinking the whole situation. After fixing the leaks/thermostat and replacing the head gaskets and resurfacing heads as needed we have yet to see the same vehicle blow head gaskets again.
spddm0n: (2017-02-17 23:14:05)
I think you are over thinking the whole situation. After fixing the leaks/thermostat and replacing the head gaskets and resurfacing heads as needed we have yet to see the same vehicle blow head gaskets again.
Yes, but that could be for various reasons…perhaps they no longer own the vehicle. Perhaps they have moved. It's probably not enough information to suggest the problem doesn't repeat, but you could be right. If you look at clubxterra.org, there is evidence people are experiencing multiple HG failures. People are heart-broken. These vehicles end up being a throw-away vehicle. They don't sell at auctions for more than a few hundred bucks, according to my used dealer friends. I'm trying to find a better way to keep them on the road. The service to replace the HG's at your dealership must be approaching or exceeding $4K now-a-days. [archived image: smile.png] The only way I can see is to buy them, find the correct solution to repair them, and re-sell them for a reasonable price that doesn't require a $140/hr dealer service price tag. [archived image: smile.png]
NissanEgg: (2017-02-18 13:41:49)
You have to take your observations on clubxterra with a grain of salt. The vast majority of SUV owners are extremely mechanically or maintenance incompetent. Same holds true for just about any group of auto owners. Yes they may be savvy about their vehicle, but lack big time in maintaining their vehicle. And by maintaining I mean more than just regular oil changes and actually fixing things as they go bad under hood instead of waiting and waiting until something drastic happens like a head gasket going bad.
Another prime example I use are your typical Z32 owner. That is why you see so many Z32 going for dirt cheap with a massive bill of repairs waiting for the next owner. There are a few owners who actually spend money to fix them but those are a small fraction of the owners.
At our dealership we have a guy with a 02 Frontier SC 4x4 5-speed with 336k miles. Never had a head gasket issue. He promptly fixed all the minor coolant leaks and such that I mentioned in my previous post. He has even had to replace the super charger twice now, but the engine bay looks almost as clean as the day it left the factory. It's all about staying on top of repairs.
88sinZ: (2017-02-21 05:58:47)
ether overthinking it or you have a shot ass motor
the vehicles, and chassis that run the engine/trans combo that are related are pushing 20yrs at best from their latest revision. NOW they are seen as throw away USA side but they are built to last with scheduled maintenance, don't fight the truth. Just this weekend i found a leaky trans cooler line clamp on the D22 S/C during a fluid change/check, and the VG33ET Z collapsed a lifter after a hard run from sitting 2mo just to come back after a soft cruise. It's old technology and requires a bit more of a specific ear. This isn't read a code type shit bro.
spddm0n: (2017-02-26 17:06:51)
You have to take your observations on clubxterra with a grain of salt. The vast majority of SUV owners are extremely mechanically or maintenance incompetent. Same holds true for just about any group of auto owners. Yes they may be savvy about their vehicle, but lack big time in maintaining their vehicle. And by maintaining I mean more than just regular oil changes and actually fixing things as they go bad under hood instead of waiting and waiting until something drastic happens like a head gasket going bad.
Another prime example I use are your typical Z32 owner. That is why you see so many Z32 going for dirt cheap with a massive bill of repairs waiting for the next owner. There are a few owners who actually spend money to fix them but those are a small fraction of the owners.
At our dealership we have a guy with a 02 Frontier SC 4x4 5-speed with 336k miles. Never had a head gasket issue. He promptly fixed all the minor coolant leaks and such that I mentioned in my previous post. He has even had to replace the super charger twice now, but the engine bay looks almost as clean as the day it left the factory. It's all about staying on top of repairs.
Thanks for the reply. I agree that a lot of "owners" are not savvy in most things mechanical about their vehicles, but the design target of any major manufacturing company is to build something that requires little understanding on the part of their customers (think the slogan for VW - "Drivers Wanted"). Few achieve this with any satisfactory remark, aside from Toyota in the 80's and 90's.
I would offer the perspective of achieving a condition of "no HG failure in 336K miles, by performing all the "difficult to determine maintenance" along the way, would not be considered an accomplishment. It may be accurate to extrapolate these findings to suggest that it is possible to NOT blow the gasket if the owner is able to detect and afford to pay for all the little coolant leaks along the way, but that also suggests a poor design in the first place. Why is the engine constantly leaking coolant?
In my perspective, if the primary cooling channel is unobstructed (no casting flash), then the minor leaks would not cause a major gasket/engine failure. You can't ignore the evidence of all the people on the websites that experience this failure. Whereas there isn't an good/fast way to determine this, probably without monitor EGR temperature of the back two cylinders (all of them would be better), on an engine with and without the block modification, to know if there is a wide temperature variance to suggest premature failure. If the turbo engines are failing to do detonation in these back two cylinders, you could suggest this is an issue and that boost causes the even more premature failure (accelerated scenario).
I plan to port one of the blocks I have, to clear out the casting flash, and see what happens.
spddm0n: (2017-02-26 17:13:26)
ether overthinking it or you have a shot ass motor
the vehicles, and chassis that run the engine/trans combo that are related are pushing 20yrs at best from their latest revision. NOW they are seen as throw away USA side but they are built to last with scheduled maintenance, don't fight the truth. Just this weekend i found a leaky trans cooler line clamp on the D22 S/C during a fluid change/check, and the VG33ET Z collapsed a lifter after a hard run from sitting 2mo just to come back after a soft cruise. It's old technology and requires a bit more of a specific ear. This isn't read a code type shit bro.
Hmmm…or I have three shot-ass motors, and the folks at clubxterra.org all have shot-ass motors too. [archived image: smile.png]
What evidence do you have to support "built to last"? There is a lot of evidence against that statement. How long is "built to last" in your mind? 40,000 miles? 80 thousand? 20 years? 30 years?
Dont' even get me started about the shitty Nissan clamps. I've converted all those shitty clamps to fuel line clamps. I found BMW clamps that I thought might work the best, but settled on a Napa fuel line clamp that won't stretch over time, causing our less experienced drivers and repair techs to just keep clamping them down until they damage all the hoses. [archived image: smile.png]
NissanEgg: (2017-02-26 17:24:33)
Like I said earlier, vast majority of Xterra and any SUV owner is completely ignorant when it comes to maintenance. The small number of people of the SUV population actually on the forums are experiencing issues as a result of a previous owner's lack of maintenance.
I work on these engines and vehicles daily and the number of them that require headgasket replacement are small, maybe 2-3 a year out of the 125 or so different Xterra/Frontiers with the VG33 we service at our dealership. And of those needing headgasket are new to our dealership and are very nasty under the hood and some so built up with sludge under the valve covers that you cannot even see the lifter plates and head bolts. There is even a doctor who has owned a 2-door V6 5-speed 4wd Pathfinder since 1987 that has not had to have a headgasket job and it is his daily driver with over 340k miles. Yes he has had to change out all the pesky coolant hoses due to leak and valve cover gaskets and surprisingly no sludge built up in the heads, and that is because he is one of the few people willing to spend money to fix everything wrong as it happens.
spddm0n: (2017-02-26 22:48:40)
I don't disagree with the possibility of a head gasket lasting longer than most I see failing, but it still doesn't make sense that there are this many failures (even in the small sample set of the forums and other websites of Nissan complaints). I don't know of "any" other car that experiences this frequent and early HG failure, not even American cars. [archived image: smile.png] There is certainly "some" issue here. If the small leaks are causing this failure, then the leaks are the problem…also unacceptable. I would add, if the engine had proper cooling to begin with, the little leaks are likely to never pose a problem. I've been driving around my Toyota shop truck for miles and miles with a leaking water pump. The cooling system is rarely full, thus less cooling than optimal, but still adequate. I think the Nissan block may be challenged in it's original design and should be considered when rebuilding. I would be interested to see if the same casting flash was allowed in the VQ40DE block.
I've never pulled open the block in my truck, but I have pulled open the block (removed freeze plugs) in the block of my Toyota MR2 (3SGTE), and there is NO evidence of casting flash. It is completely smooth and suited for excellent cooling. That block was first designed in 1986 (based on the 3SGE manufactured in 1984), so it has similar age/design time as the VG33. I can't say for sure, but I think the block cooling capacity is degraded due to the casting flash.
I have seen some poor maintenance, like the underside of the valve covers that look like a volcano went off and left dry black ash under them. [archived image: smile.png] This would not necessarily affect the cooling capacity, but certainly could be part of the reason these engines are commonly throwing rods. [archived image: smile.png] I also think that when the HG's fail, people are fixing the HG's without attention to the main and rod bearings. I think there are a lot of engine failures as a result of coolant in the oil after the HG's fail. I removed the bearings from a 150K mile engine after a HG, where the PO said they only drove it a couple miles after the failure occurred. The bearings showed significant wear. It's had to say the condition of the bearings before the failure, but they certainly showed wear.
I think the safe bet to keeping these engines on the road are to improve the cooling when it's appropriate (engines removed) and install all new bearings and gaskets (might as well put in new rings and hone the cylinders too).
88sinZ: (2017-02-27 02:16:41)
so you're telling us that an engine implemented in 1983 was designed in 1986 based on a yota engine??
and you call any leak a small leak? any leak is a MAJOR leak, there's no compromise
then you say you've never cracked open a VG series and you assume all this BS? nothing personal man, but don't claim shit you've never dealt with
you gotta do some more research bro, and i say that in the most respectful way i can
the XT and Fronti radiators are shit and have shit airflow, the A/Ts are easy to over heat just crawling sand beaches (NCBBA registered SVE D22) due to no A/T independent cooler. you ether have to blast heat or pop the hood on hot summer days. they would easily benefit from increased capacity radiator and an electric auto+manual operated fan
spddm0n: (2017-02-27 02:56:41)
so you're telling us that an engine implemented in 1983 was designed in 1986 based on a yota engine??
and you call any leak a small leak? any leak is a MAJOR leak, there's no compromise
then you say you've never cracked open a VG series and you assume all this BS? nothing personal man, but don't claim shit you've never dealt with
you gotta do some more research bro, and i say that in the most respectful way i can
the XT and Fronti radiators are shit and have shit airflow, the A/Ts are easy to over heat just crawling sand beaches (NCBBA registered SVE D22) due to no A/T independent cooler. you ether have to blast heat or pop the hood on hot summer days. they would easily benefit from increased capacity radiator and an electric auto+manual operated fan
Hmmm…sorry, you are misunderstanding me, again. I've not cracked open the block in my "Toyota" truck. I have three open VG's right now.
Im also saying that the casting flash evident in my 3SGTE block (design came out in 1986, based on a 3SGE block developed in 1984. Not sure where you got 1983). I only bring this up because it has been stated that age was a factor in these engines; that they were an old design. I disagree. The casting flash is a result of lack of care in the manufacturing process.
Lastly, I'm saying that I can run a small leak in the water pump on my Toyota truck FOREVER, without it causing the cooling issues that NissanEgg suggests may be contributing to HG failures in the VG's.
I'm further saying that I believe the cooling issue from these "minor" leaks he speaks of, would likely be less of an issue with better cooling in the block to begin with. Or, as you stated, perhaps the radiators are really not providing enough cooling. That could be another factor I hadn't considered yet. I have noticed there may be a popular aftermarket (thicker) radiator. Perhaps that is something I could test as well. [archived image: smile.png]
88sinZ: (2017-03-04 07:47:06)
nah man, what im saying is the VG series (specifically the VG33X(Y) XT and Frontis) had shit air flow and if you're crawling them they need a engine and tranny cooling upgrade… that's all.
Yotas are normally have head/block material matching i.e. alum/alum resulting in uniform heat expansion and anode/cathode non-subjugation.
We can disagree on leaks, but we can agree how they effect overall
I will say there's a grey line definition of early and late VG33's the later being the better option in a short block option
spddm0n: (2017-03-04 19:04:26)
nah man, what im saying is the VG series (specifically the VG33X(Y) XT and Frontis) had shit air flow and if you're crawling them they need a engine and tranny cooling upgrade… that's all.
Yotas are normally have head/block material matching i.e. alum/alum resulting in uniform heat expansion and anode/cathode non-subjugation.
We can disagree on leaks, but we can agree how they effect overall
I will say there's a grey line definition of early and late VG33's the later being the better option in a short block option
I have late 80's early 90's Toyota vehicles, so they are all cast iron blocks. This makes cooling very important, but the care that was given to the block casting is highly improved compared with the VG33E, so it likely experiences fewer issues. My shop truck V6 is old and tired, so when I pull it (someday), I'll inspect the block to see if it looks like other Toyota blocks or this pesky VG33E. [archived image: smile.png]
I have a VG33E from an Elgrand (JDM). I'm not sure of the age (no VIN), but it has the same cooling channel issue as all my 2000 Xterra VG33E's. What have you seen improved in the later VG's?