Forums/Z31P/z31-performance-upgrade-forums engine-mechanical-aa/OWO Head Porting & Polishing
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BLOZ UP: (2014-02-18 14:45:06)
I doing my first ever P&P on some OWO heads for my turbo 3.3L build in my 280Z. This will be paired with Schneider 274 turbo cams and springs.
Just by looking at the W-series (V52?) heads and these, you can tell the casting is better.
I got started the other day just trying out some different tools. In 1/8" shank I have a Dremel (kind of beat up, missing a collet for my pencil adapter) and the HF pencil die grinder, then for 1/4" shank I have a few HF die grinders. I was hoping to find an electric grinder with 1/4" shank, but I can't seem to.
Anyway, here are some starting pics:
Intake:
Exhaust:
The marker marks are from this guy at a local speed shop who says I should take out some in that area. I pretty much don't trust a word he says after he claimed repeatedly that ceramic coating stainless steel exhaust manifolds would reduce performance. I posted about that on HybridZ. I've been reading David Vizard's book and am using that and a few other resources to help out, but I think I'll be keeping it simple here. My plan so far:
Remove casting marks "Gasket" match intake ports with lower intake manifold Polish lower intake manifold ports Polish intake and exhaust ports (exhaust is already the same ID as my turbo manifolds) Polish combustion chamber 3 angle valve job Cams
If I start taking out lots of material I'll have to make templates and make a cheap flow bench to really bring any benefits out instead of just shooting in the dark. Unless anyone here has suggestions on where to remove material.
BLOZ UP: (2014-02-18 14:47:01)
After about 15 mins of playing around with a dremel:
This is really not that hard or mysterious. That didn't take long, but I can see it getting difficult to reach in the deeper parts of the port.
707Redz31: (2014-02-18 20:49:32)
Why are going to polish the intake ports? On turbo builds I've heard nothing but that it isn't beneficial or necessary.
zdriver_kado: (2014-02-18 21:16:58)
Looks like you made a decent start. Here is a link to Moto IQ's OWO headwork for their project pathfinder buildhttp://www.motoiq.com/MagazineArticl…-Headwork.aspx; I will be doing my own heads as well and this is exactly how I want mine to end up. "The idea was to keep the port volume down to keep the velocity up so as to enhance low-end torque."
Another link straight to DPR site http://www.dprracing.com/snissan.html can give you good ideas what else you can do while your there.
BLOZ UP: (2014-02-18 21:27:17)
Why are going to polish the intake ports? On turbo builds I've heard nothing but that it isn't beneficial or necessary.
So the claim is that polishing the intake at areas after the fuel injectors is bad. I haven't seen any data to back this up. I realize it affects the tau layer, but I can't find anything showing negative consequences. Further, fine polishing either side adds a negligible performance benefit--but I'm aiming for reduced carbon build up, especially on the exhaust side.
So, I can leave the intake ports as-is for now, until someone chimes in to let me know what's what.
BLOZ UP: (2014-02-18 21:39:51)
Looks like you made a decent start. Here is a link to Moto IQ's OWO headwork for their project pathfinder buildhttp://www.motoiq.com/MagazineArticl…-Headwork.aspx; I will be doing my own heads as well and this is exactly how I want mine to end up. "The idea was to keep the port volume down to keep the velocity up so as to enhance low-end torque."
Another link straight to DPR site http://www.dprracing.com/snissan.html can give you good ideas what else you can do while your there.
I see a couple things that I'm not sure of:
They radius the quench edge They Deshroud the valve
I've been reading that the valve shroud in the chamber is designed to swirl the mixture together, and that removing it is not good. I've also read that radiusing the quench edge can remove the edge hotspot, but reduce performance. Ugh. So much conflicting info.
But they do chow down on the valve guide. Guess I can try to do that…
Z_Karma: (2014-02-18 21:45:08)
I P&P the intake and exhaust on my 84T motor with a dremel and wrapped sanding bits.
I had no clue as to what i was doing. Smooth all the things!
Intake 1600X1200
I gasket matched things as best i could. It's been running great since 2003.
les_joey_paul: (2014-02-19 00:07:22)
From what I've learned talking to my coworker who used to own a performance build shop, has experience porting, etc, and from my reading, you can port and polish all the way to the intake valve, but stop polishing at the valve, continue to port through to the chamber.
This promotes the fuel mixing with air once it's sucked pushed passed the intake valve. Otherwise it will pool up and cling to the polished surface, which is not what we want.
When porting you want to make the most straight and direct path in and out of the combustion chamber.
This effectively removes the oem "bumps" or velocity swirling humps in the casting.
707Redz31: (2014-02-19 00:28:21)
I got schooled in what should be done by Dave rebello of rebello racing when he came and picked up my engine to have him do it up right. Things he told me (some of which is common knowledge on here):
-polish the exhaust
-for a mild build on our motors oversized valves are not worth the effort and money
-intake porting is essential but polish is useless and is better off NOT done for turbos. (N/A is different)
-w-series heads are much better than the early heads
-arp hardware isn't always the best option for mild-moderate street builds if you aren't willing to open up the motor to final retorque within a years time of the motor being put together.
I know not all applies here but I just figured I'd pass along that from an engine building master. I pick up my engine on Thursday. Interested to see his work and the dyno results when I get it back in the z.
michaelp: (2014-02-19 00:38:05)
I got schooled in what should be done by Dave rebello of rebello racing when he came and picked up my engine to have him do it up right. Things he told me (some of which is common knowledge on here):
-polish the exhaust
-for a mild build on our motors oversized valves are not worth the effort and money
-intake porting is essential but polish is useless and is better off NOT done for turbos. (N/A is different)
-w-series heads are much better than the early heads
-arp hardware isn't always the best option for mild-moderate street builds if you aren't willing to open up the motor to final retorque within a years time of the motor being put together.
I know not all applies here but I just figured I'd pass along that from an engine building master. I pick up my engine on Thursday. Interested to see his work and the dyno results when I get it back in the z.
I will correct something here, though…W-series Z31 heads are 100% identical to early Z31 heads. They're even the same castings. The *ONLY* difference is Nissan drilled steam holes in them during the machining process.
85E and OWO heads are much much better, but arent W-series technically.
youngfg: (2014-02-19 01:48:03)
I have been doing some flow testing on heads lately with an cylinder head expert, I put some info in this post.
http://z31performance.com/showthread…s-section-pics
My testing has shown that the OWO heads aren't the best totally stock.
The OWO head does have a better SSR, but no one notices that the R21V has a better bowl shape to the port.
The good thing is you can copy the bowl shape from the R21V to the OWO with a good SSR and get even better flow.
I decided to concentrate on the OWO heads, so I have done a lot of testing to see what works the best.
The stock valve and seat are where you can get the most improvement.
Porting the with the stock valve and seat really only helps the flow at .5" and above, that won't help much with the cams you can get for VG30's
I tried a 35deg. seat angle on a stock valve, that's supposed to help flow at low lift, it really didn't change the flow much.
I tried a typical multi-angle valve job on a stock valve, it helped the flow were it matters the most, at low lifts.
I tried the +1mm valve with a multi-angle valve job, and was disappointed with the increase in flow.
I added a 30 deg. backcut to the +1mm valve, it helped the low lift flow.
We tried one more thing increasing the throat. The biggest increase came from opening the throat to 90% of the valve diameter.
We got the peak flow up to 190 CFM with the velocity probe in the port at .425" lift, 28" of water, with velocity of 326 ft/sec
Here is what I finished up with for flow on the intake port.
At 28" of water
1.528" throat diameter, 30deg. backcut on +1mm valve
Lift in Flow cfm
.1 61
.2 113
.3 156
.4 186
.45 186
.5 184
For reference stock head
Lift in Flow cfm
.1 58
.2 111
.3 140
.4 160
.5 164
We are not finished working on the heads yet, still have the exhaust to go, and I still have some things to try on the test head I have.
I have also tested with the intake on.
The lower intake works fine after a little clean up, but the upper knocks off about 10% of the flow, which makes no sense, I am only flowing one cylinder through it.
I just gutted a stock intake to try it out when I get a chance.
Attached Files
140214_0007.jpg (85.3 KB)
zdriver_kado: (2014-02-19 01:53:41)
I see a couple things that I'm not sure of:
They radius the quench edge They Deshroud the valve
I've been reading that the valve shroud in the chamber is designed to swirl the mixture together, and that removing it is not good. I've also read that radiusing the quench edge can remove the edge hotspot, but reduce performance. Ugh. So much conflicting info.
But they do chow down on the valve guide. Guess I can try to do that…
Your right. I forgot we were talking turbo VG. [archived image: tongue.png]
707Redz31: (2014-02-19 03:41:05)
I will correct something here, though…W-series Z31 heads are 100% identical to early Z31 heads. They're even the same castings. The *ONLY* difference is Nissan drilled steam holes in them during the machining process.
85E and OWO heads are much much better, but arent W-series technically.
oh good lord. Did 85E castings come on anything but w-series motors?
The 85E castings came out in mid '87 I think in Z31s. These are the heads of the "W series" VG30 that everybody wants due to their better intake port shape
WTMP: (2014-02-19 04:48:59)
I have been doing some flow testing on heads lately with an cylinder head expert, I put some info in this post.
http://z31performance.com/showthread…s-section-pics
My testing has shown that the OWO heads aren't the best totally stock.
The OWO head does have a better SSR, but no one notices that the R21V has a better bowl shape to the port.
The good thing is you can copy the bowl shape from the R21V to the OWO with a good SSR and get even better flow.
I decided to concentrate on the OWO heads, so I have done a lot of testing to see what works the best.
The stock valve and seat are where you can get the most improvement.
Porting the with the stock valve and seat really only helps the flow at .5" and above, that won't help much with the cams you can get for VG30's
I tried a 35deg. seat angle on a stock valve, that's supposed to help flow at low lift, it really didn't change the flow much.
I tried a typical multi-angle valve job on a stock valve, it helped the flow were it matters the most, at low lifts.
I tried the +1mm valve with a multi-angle valve job, and was disappointed with the increase in flow.
I added a 30 deg. backcut to the +1mm valve, it helped the low lift flow.
We tried one more thing increasing the throat. The biggest increase came from opening the throat to 90% of the valve diameter.
We got the peak flow up to 190 CFM with the velocity probe in the port at .425" lift, 28" of water, with velocity of 326 ft/sec
Here is what I finished up with for flow on the intake port.
At 28" of water
1.528" throat diameter, 30deg. backcut on +1mm valve
Lift in Flow cfm
.1 61
.2 113
.3 156
.4 186
.45 186
.5 184
For reference stock head
Lift in Flow cfm
.1 58
.2 111
.3 140
.4 160
.5 164
We are not finished working on the heads yet, still have the exhaust to go, and I still have some things to try on the test head I have.
I have also tested with the intake on.
The lower intake works fine after a little clean up, but the upper knocks off about 10% of the flow, which makes no sense, I am only flowing one cylinder through it.
I just gutted a stock intake to try it out when I get a chance.
Just curious where in the port you were 325 ft sec. with the velocity probe? Or is that the average velocity?
Also noticed that you had little gain from from the convergence to .500, that is usually caused by excessive air speed over the short turn, was wondering what kind of csa you had approaching the short turn.
youngfg: (2014-02-19 15:57:30)
That speed was in the middle of the port. I don't know the csa measurement, I will try remember to get that next trip.
On another subject, my head porting expert/mentor says, "I can make a head that will win a flow bench race, or a head that will win a real race, which do you want?"
BLOZ UP: (2014-02-19 16:37:35)
Right now? Flow bench race to be honest. Thanks for taking the time to do this. Can you get some numbers at 10" of water? I've been reading that getting two (or more) pressures simulates a running engine better than just the standard 28". I realize this involves doing everything twice over.
300zxturboftw: (2014-02-19 18:10:52)
Kind of off topic, but are there any good books/reading material on this topic?
BLOZ UP: (2014-02-19 18:17:12)
I'm going off David Vizard's How to Port & Flow Test Cylinder Heads
I also received some 1/8" shank carbide bits, a set of 10 for $30 from eBay. They actually look really decent. And with 10 of them, if they turn out to suck it should still get me through one set of heads.
WTMP: (2014-02-20 01:14:15)
That speed was in the middle of the port. I don't know the csa measurement, I will try remember to get that next trip.
On another subject, my head porting expert/mentor says, "I can make a head that will win a flow bench race, or a head that will win a real race, which do you want?"
I agree with making heads that make power vs just flow a lot of air, which is why I work on csa, air speed and efficiency, then cfm.
BLOZ UP: (2014-03-05 15:41:31)
So I sent my cams in weeks ago, and called Schneider up just the other day. Apparently the shipping label and separate cam info sheet were torn off the poster tube I used. I thought it was clever, clearing something went wrong. Anyway, they got the cams and now knew who they belonged to. Got the 274-70H-14 grind coming back soon, so I'm going to attempt to finish the heads real quick.
Also started working on a couple more ports. The plan now is to remove the cast marks from the sides, blend the seats, grind out a little more of the bowl on the far side radius, polish the exhaust and chamber well, and smooth out the intake.
BLOZ UP: (2014-03-24 18:03:24)
Here's what I've done. I didn't apparently take pics of the finished product but these are close:
The first one took a day, the second only a few hours. I could have done better on the long side radius after the valves, but the bits I had just wouldn't work with the angles I could get at. Most of the work centered around the valve opening where the cast finish of the port met the machining of the valve seat. Most of that work was smoothing out the short side radius. Otherwise I just removed casting marks from the sides of each port, and cleaned up the entire port. There was, however, a kind of "lip" on the exhaust side of the chamber on one of my heads--it appeared to be a casting/machining flaw. It was pronounced on one head, and only just noticeable on the other. I removed both. I did not radius the lip to the quench area. I've read conflicting info for/against it but decided to play it safe and skip it for now.
After the carbide burrs, I used 80 grit on the entire head. Then for the compression chamber and exhaust I went to 120 grit (the finest my kit came with), then polishing rubs. I ended up destroying most of the polishing pieces and had to jerry-rig the rest to finish. It's hard to tell in the pics but the exhaust and chamber really polished up nicely. There's a few pits here and there but I think it's fine for my first P&P job. Also, the chamber on cylinder #6 (I think) polished up extremely shiney--I couldn't get the others quite like it. I must have been using a worn 120 grit roll on it or something. Whatever, can't tell by touching it.
I read that most of the gains are going to be around the valve opening, so that's what I focused on. It also seemed to be where most of the improvements could be made due to machining marks. So this work plus a 3 angle valve job should match up well with my cam and give me all my horsepowers.
Now off to get a 3 angle valve job.
88sinZ: (2014-03-26 05:57:55)
lol +0.500 lift
I'm just reading along wondering how often you guys plan to burn seats, feather valves, and rebuild your drive train - a street engine is not a race engine. Stick to a solid 2 angle with the VG.
Glad to see you coming onto the OWO world BLOZ. A simple job can improve characteristics
of the OWO 2 fold.
intake charge density > intake charge velocity
G-E: (2014-03-26 06:21:19)
Needs more gasket matching!
Gregmatic: (2014-03-26 13:53:54)
3 not good on VG heads? A 5 angle I could understand, but I thought a 3 angle was fairly standard....
300zxturboftw: (2014-03-26 14:02:00)
3 not good on VG heads? A 5 angle I could understand, but I thought a 3 angle was fairly standard....
This was my assumption. I've always done 3 angles
youngfg: (2014-03-26 14:08:05)
In the testing I have done, the valve job is the most influential thing in getting good low lift flow, and I mean flow under .4"
Over .4" the port shape determines flow, but you can't get a cam with enough lift to make the flow at high lifts matter.
BLOZ UP: (2014-03-26 15:03:16)
Needs more gasket matching!
Yeah I will. The gaskets I have are pretty shitty. For the VG30 I've seen and used some nice metal ones with rubber port openings. I'd like to find those and work from that. Also, I need to clean up the lower intake to see how much matching I need to do. But, I can do this after the valve job and it won't take long.
lol +0.500 lift
I'm just reading along wondering how often you guys plan to burn seats, feather valves, and rebuild your drive train - a street engine is not a race engine. Stick to a solid 2 angle with the VG.
Glad to see you coming onto the OWO world BLOZ. A simple job can improve characteristics
of the OWO 2 fold.
intake charge density > intake charge velocity
Woah, everything I've read says 3-angle gets you the most bang for your buck. 4 and 5 angle give diminishing returns.
3 not good on VG heads? A 5 angle I could understand, but I thought a 3 angle was fairly standard....
Me too. Didn't think it burned up seats.
88sinZ: (2014-03-29 05:31:08)
3 not good on VG heads? A 5 angle I could understand, but I thought a 3 angle was fairly standard....
This was my assumption. I've always done 3 angles
While multi-angle is beneficial, the VG seats are ferro-iron. with that comes great maintainability and wide arrange of options in the head shop.
If you plan to turn 6K on the reg with a street/long term set up stick with a 2 angle, like the OEM set up of 15/45.
focus on more than seat parameters, push more air and fuel.. quit nit picking
88sinZ: (2014-03-29 05:34:36)
sUre there's benefits, but how often are you planning to compression check your set up?
300zxturboftw: (2014-03-29 16:45:08)
=DUOTE=88sinZ;357261]sUre there's benefits, but how often are you planning to compression check your set up?[/QUOTE]
For my set up probably after every track day
=D
n-sane-1: (2014-04-09 05:37:10)
Bloz Up, kudos brother. I certainly did not have the nadz to do this myself. I actually sent my heads to Dan from DPR Racing to handle the work. I just don't have the patience for the kind of work. So how did the job turn out? Do you have a status up date?
BLOZ UP: (2014-04-09 16:22:19)
Motor's not assembled yet. Have heads on, just need some timing belt parts and some oil lines.
BLOZ UP: (2014-04-09 17:13:58)
Oh, but I did get it back from the machine shop. I can't tell if it's 3 angles or not on the valve seats. Feels smoother, I guess.
n-sane-1: (2014-04-13 15:54:21)
Yeah, not sure myself. I should be getting my heads back today. Stoked about getting the old girl back together. I have to say, that Dan has been a great help in the process. He was kind enough to consult me during my rebuild. Saved a ton of cash with his help. Looking forward to see how yours turns out. When do you think you will have your baby back together? How much more work do you have to get done? How about some more pics!!??
BLOZ UP: (2014-04-14 00:10:26)
I have a build thread on HybridZ that I keep pretty up to date: http://forums.hybridz.org/topic/95156-bloz-up/
I have an issue with the VG33 harmonic balancers, but it should be soon. Within the next month or so.