Forums/Z31P/z31-performance-upgrade-forums engine-mechanical-aa/All my cam gears are out of spec (run-out)!?
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spddm0n: (2017-07-11 18:52:55)
Since I spent so much time setting up a rig to be able to measure the end-play of the VG30 camshafts in my VG33E, I simply flipped the head around on the bench and began to measure the cam gear run-out. As it turns out, 4 out of 6 gears are out of spec; both on the RH side of the engine. How does that happen? [archived image: smile.png] Maybe the specs (FSM) are wrong. ??
I was also able to rig up my gauge from my cylinder bore gauge that is sensitive to .0001".
The spec says they should have less than 0.0040" run-out.
I measured:
1. USDM VG33E (LH), 150k miles: Total Run-out= 0.0029"
2. USDM VG33E (RH), 150k miles: Total Run-out= 0.0057"
3. USDM VG33E (LH), 97k miles: Total Run-out= 0.0047"
4. USDM VG33E (RH), 97k miles: Total Run-out= 0.0054"
5. JDM VG33E (LH), 65k miles: Total Run-out= 0.0037"
6. JDM VG33E (RH), 65k miles: Total Run-out= 0.0050"
7. USDM VG30E (LH), 110k miles: Total Run-out=
8. USDM VG30 (RH), 110k miles: Total Run-out=
I haven't measured the gears that came on the VG30 cams I bought.
Looks like the RH-side cam gear sees most of the abuse. The other thing is, I know the camshaft I'm bolting them to has some end-play as well, and that would likely add to the total run-out.
For example, the USDM cam gear in test number 4. above, with a total run-out of .0054", also has a total end-play in the camshaft of 0.0015". That could, technically, bring the total run-out down to about 0.0039" and just be within spec. (I thought it was odd that Nissan would suggest measuring run-out of the cam gear while bolted to a shaft that would technically have end-play that could affect the already tight specifications).
Any idea what might cause these to have so much run-out? Or, is 5-6 thousands reasonable (even though the spec says 0.004")?
spddm0n: (2017-07-28 18:40:22)
Problem solved. Turned out the face of the camshaft that surrounds the snout where the front bolt holds on the cam gear is bowed out and is convex shaped. Not sure what could have caused that. [archived image: smile.png] I might be able to turn them down on a lathe. [archived image: smile.png] I purchased another set and they seem to be fine. [archived image: smile.png]