VTC and other stuff

Seahag · May 7th, 2003, 12:26 PM

I took off my valve cover to take off the top chain guide (as Nissan recommended). I have been experiencing rattling noises. There seem to be alot of slack between the 2 top chain sprockets.(cam to cam)

I took off the guide and put things back together and fired it up. Noise was there but still apparent.
After more research I realized that this model has the VTC.
Could the slack be there to allow the cams to be adjusted through the VTC system?
If so how much is normal?
Could the chain tensioner be too weak to return the cam to is normal location and causing the chain to sag between cams?

Chris
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Centurion · May 7th, 2003, 05:21 PM

You took off the guides but you did replace them with new ones, right? Your post implies that you left them out.

Seahag · May 7th, 2003, 05:23 PM

Thats what nissan recommended..
I did leave the top one out

the noise isnt coming from the guides now.

SRV1 · May 8th, 2003, 11:34 PM

Quote:

Originally posted by Seahag
Thats what nissan recommended..
I did leave the top one out

the noise isnt coming from the guides now.

He is correct. Nissan say take them out, but i did that only when i did a chain. I wouldnt take it out of a high mileage timing chain due to the fact that you are making more slack and the chain would rattle more.

James

azkicker0027 · May 10th, 2003, 06:27 PM

wait, is there a buletin on this or something?? removing the what form the what?? chain tensioner guides?? and leaving them out?? huh???

blownb310 · May 10th, 2003, 09:16 PM

Yes there was a bulletin on it. It was due to Nissan discontinuing the mounting holes for the upper guide in the replacement heads. Their advice was to throw the upper chain guide away if you were changing the head with a service replacement. It certainly doesn't hurt to have it in place on your original head though. And there is nothing to be gained by removing it.
Seahag, unless the engine is running, there won't be any oil pressure for the tensioner to hold the chain tight. So by having slack would not be abnormal with the engine off. But if you have a bad upper or lower tensioner and the chain had slack during engine operation, it might be time for a set of timing chains.

Seahag · May 11th, 2003, 05:22 PM

very interesting.. Oil pressure used in the tensioner..
DUH.. I put some oil in and the car runs fine now.

I feel stupid.

Chris
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blownb310 · May 11th, 2003, 05:35 PM

Quote:

Originally posted by Seahag
very interesting.. Oil pressure used in the tensioner..
DUH.. I put some oil in and the car runs fine now.

I feel stupid.

Chris
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***** Oh well, you learn something every day.