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Thread: Need some valve train help.

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Posts: 61-70 of 106
2012-12-04 14:34:14
#61
Originally Posted by nissanboi
Originally Posted by ashtonsser
Again who knows man. Maybe during removal something happened that caused the cam to tweek some. Most people dont realize how important it is to loosen the cam cap bolts a turn or so at a time and to do it evenly down the line. The cam can bend very easily if you dont do it properly.

Anyways there is only one way to find out and thats to put it on stands and rotate it and look for variations at the end of the cam.


This is true my friend (a dealer tech) was helping me and watched me turn the cams 1/4 turn at a time evenely and was like WTF why are you taking that long. Also, I helped another friend do a head on a ZX2 and we tightened them down in order put not evenly we went to put the VC on the next morning and guess what the exhaust cam was snapped in half. Thats when I learned my lesson with any internal engine part to take your time and go SLOW and EVEN


That's exactly how I did them, slowly. I used the same procedure/technique/torque settings all 3 times. Everything was done per the FSM. Twice I installed the S3's and once I installed the stocker back in. The stocker is running fine as it did before.

Once I get something to measure the cam with, we can all get a better idea of what's going on here.
2012-12-04 14:57:11
#62
I am waiting patiently to see what the problem was because honestly I am dumbfounded.
2012-12-04 17:33:05
#63
Even though you have the HLA, the non-slotted shim under the rocker is selective.
You typically do not have to change the lash on a cam swap, but it does come up occasionally. Mass produced "identical" parts are not always identical due to mfg tolerances.
The ESM lists 17 different shims from 2.800mm to 3.200mm.
If you do not have access to FSM, PM me and I will get you a PDF via email or PM.

I re-read your post about the compression pressures on the stock cam. ESM lists the MINIMUM pressure at 149psi.
Maybe the exhaust valves are "tuliped"? This places the valves higher in the seats and decreases lash.
Last edited by freakflier on 2012-12-04 at 17-45-05.
2012-12-04 19:28:29
#64
Originally Posted by freakflier
Even though you have the HLA, the non-slotted shim under the rocker is selective.
You typically do not have to change the lash on a cam swap, but it does come up occasionally. Mass produced "identical" parts are not always identical due to mfg tolerances.
The ESM lists 17 different shims from 2.800mm to 3.200mm.
If you do not have access to FSM, PM me and I will get you a PDF via email or PM.

I re-read your post about the compression pressures on the stock cam. ESM lists the MINIMUM pressure at 149psi.
Maybe the exhaust valves are "tuliped"? This places the valves higher in the seats and decreases lash.


I don't mean to sound like a dick...but did you read through what I had to say in this thread? I've referred to using the FSM multiple times. It even states in the FSM that the slotted disc only has one size available.

The valves are fine. The stock cam never ran better.
2012-12-04 19:48:16
#65
Originally Posted by hammerin
It even states in the FSM that the slotted disc only has one size available.

The valves are fine. The stock cam never ran better.

I said the NON-SLOTTED shim is selective.
2012-12-04 20:26:23
#66
Hank, you are not understanding us when we suggest you re-shim the valves for the cam. It’s to compensate for the out of tolerance or bad cam. We already know your valvetrain checks out and so the S3 exhaust cam is the likely culprit.

Now the question, how are you going to resolve this? Are you going to send the cam back to the manufacturer for warranty (I doubt it’s still under warranty once you install it) or have it straighten out for $$ money? Or you can simply re-shim the two exhaust valves for cheap and a little of your time.

Even though the factory has only one size for the slotted shim, what is stopping you from grinding it down. I do this all the time to the DE and VE when I’m in a pinch. Finish off the shim with 1000 grit or higher.

You can do two things, either get thinner shims or grind the base of the hla.
2012-12-04 20:34:58
#67
Originally Posted by freakflier
Originally Posted by hammerin
It even states in the FSM that the slotted disc only has one size available.

The valves are fine. The stock cam never ran better.

I said the NON-SLOTTED shim is selective.


Yes, and that shim is there to get the two rocker arms on the same plane (which they are), not to adjust the lobe to rocker clearance. The hydraulic lash ADJUSTER does that with oil pressure. And I've determined my HLA's are working properly. There's something up with the cam itself.
2012-12-04 20:38:28
#68
Originally Posted by 5speed
Hank, you are not understanding us when we suggest you re-shim the valves for the cam. It’s to compensate for the out of tolerance or bad cam. We already know your valvetrain checks out and so the S3 exhaust cam is the likely culprit.

Now the question, how are you going to resolve this? Are you going to send the cam back to the manufacturer for warranty (I doubt it’s still under warranty once you install it) or have it straighten out for $$ money? Or you can simply re-shim the two exhaust valves for cheap and a little of your time.

Even though the factory has only one size for the slotted shim, what is stopping you from grinding it down. I do this all the time to the DE and VE when I’m in a pinch. Finish off the shim with 1000 grit or higher.

You can do two things, either get thinner shims or grind the base of the hla.


I'm not going to adjust internals that never intended to be adjusted because of a bad cam, sorry. The correct answer is to get a good cam. But first I need to check the one I have to make sure it is indeed bad. At the moment, it's still just a hunch.
Last edited by hammerin hank on 2012-12-04 at 20-40-58.
2012-12-05 00:26:10
#69
I dont disagree with any of you just curious, jwt cams are billet correct can it really bend? I would believe a cast part (cam) would be more likely to bend than billet. But I guess there have been wierder things happen.
2012-12-05 16:47:14
#70
Update:
The base circle on the #4 lobe is 1.268". All the the base circles on the cam range from 1.267-1.270. All of the journals are 1.101-1.102". I'm not well versed enough to know if those numbers are cool or not. I'll have to pull the valve cover again and check it against the stocker's numbers. It's hard to tell by just looking at it whether it's bent or not. I might just put it back in the head without the rockers in and hand spin it. I'm busy as hell @ work. It's gonna have to wait until the weekend.
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