Timing chain replacement questions -> trying to find the best fix for "marble noise"

[SlideWise]

Ive got a few questions as to how reliable the ka24de's (91 s13) timing system is.
Do the chains and gears wear out easily(say after 200+k miles) or can you just replace the guides and tensioners leaving the original chains and gears? Is it the upper timing chain that is most prone to failure leading to damage or catastrophic failure or is the lower chain just as likely? Also how much play in each chain is acceptable and when should i start to be concerned?

Im trying to figure out how far into the timing system i should go and how much i should spend since i have the "marble in the valve cover" noise coming from my ka's timing system. Some people also say to just pull the upper chain guides as nissan rendered them useless but i dont know if i would consider that to be a proper fix or not...?

Any knowledgeable input is greatly appreciated!

[redline240sx]

Well the timing chain kit from nissan is about 120 the last time I checked, so why not changed the whole thing. But, to answer your question most people just remove the guide or replace them along with new tensioners

[SlideWise]

Originally Posted by redline240sx

Well the timing chain kit from nissan is about 120 the last time I checked, so why not changed the whole thing. But, to answer your question most people just remove the guide or replace them along with new tensioners

This is the price quote i got from nissan today though my dealer account:
Both upper guides are no longer used or considered necessary and not available.
Cam chain - 67.57
idler sprocket -84.48
crank chain - 65.57
lower left guide - 90.25
lower right guide - 21.13
upper tensioner- 74.73
lower tensioner -74.73
cam gears - 15.23 each


Still i can not find any specs on how much slack is acceptable in the upper chain and when i should be concerned(lower chain as well)??

[mxexux]

There is no slack spec because the tension is controlled by oil pressure and spring pressure from the tensioners so its not exactly fixed in a staic state. Removing the upper guides would be a proper thing to do first since it was a TSB from nissan. The timing chain noise is not that critical. I don't know how your timing chain sounds but you might be too worried about "casitrophic" failure. I have never heard of either of the timing chains breaking with normal use even with a lot of miles. If you are going to change out the timing chain I would consider also changing the oil pump; that is one thing I would have done when I did mine.

[SlideWise]

Mine sounds like this: Short video i took of the noise The noise is best heard after it starts to warm up.

Im not as worried about the chains and gears as i am about the tensioners and lower guides.

[mxexux]

Yeah... that sounds pretty bad. Have you popped off the valve cover yet to take a look? It sounds like maybe the top guide may have come loose and is rattling around. If not, it may be a good idea to check oil pressure...

[SlideWise]

Originally Posted by mxexux

Yeah... that sounds pretty bad. Have you popped off the valve cover yet to take a look? It sounds like maybe the top guide may have come loose and is rattling around. If not, it may be a good idea to check oil pressure...

The top guide was in place when i pulled the valve cover. However i removed it after noticing how easily the chain could slap the top guide and after reading how nissan has a tech bulletin on the upper guides. I have yet to restart it since pulling the guide as im pondering what my next move should be.

My engine:


The car sat for about 6 months so i pulled the valve cover and poured two quarts over the entire head before starting it. In fact i was really impressed with how clean everything looked.

My check oil light is not on, but i know it takes almost no pressure at all to trigger that thing. Ill get a gauge on it and post my findings. Since ive removed the top guide but not the upper right side guide will that cause any issues?

[mxexux]

Removing the top guide won't do anything bad. I would try and restart it now that its out. Its a little concerning though that the oil light is on since, like you said, it takes just a few psi to turn that off...

[SlideWise]

Originally Posted by mxexux

Its a little concerning though that the oil light is on since, like you said, it takes just a few psi to turn that off...

My oil light does go off as in it has at least enough oil pressure to turn the oil light off.

[Andrew@9K]

you can reuse the chains and sprockets. but it is cheaper to get a TIMING KIT from an aftermarket supplier and it brings EVERYTHING(guides,tensioners,chains). There price is usually under 100 bucks.. hope this helps -Andrew at 9k Racing

[SlideWise]

My oil pressure is good. Cold start up is around 60psi and warmed up idle it stays right around 25-30ish.

Im glad you suggested to check my oil pressure because it caused me to start up the car again after removing the top guide under the valve cover which seams to have stopped the noise. My question is there any reason i should tear back into it and remover the upper right timing guide as well or should it be fine since its not making noise any more?

Also what could cause the chain to be making that noise against the upper guide like that when it never did that 6 months ago (roughly the amount of time it sat)?


...at least im feeling much better about my engines integrity now

[240sxvaj]

Your chain will not break but it will stretch through out time. the tension applied on the chain will eventually cause microscopic stretching but not to the point where its going to break. I'm sure these chains fatigue life are designed to last longer than the engine. Unless you have other timing issue or the motor is a 700whp monster otherwise i wouldnt worry.

For the guides, make sure to remove both the upper guides, there was a situation where someones guide broke off. so be on the safe side.

[jeffary]

Originally Posted by SlideWise

Since ive removed the top guide but not the upper right side guide will that cause any issues?

Been driving around with my ticking for 6+ months now. I'm also wondering if i could just remove the top guide, and leave the right side guide alone. ?

I've heard some horror stories here and there; and dont want to deal with messing with the distributor/timing.
I know for sure my top guide is rattling, but cant tell if other is..

[Sr20Bluebird]

Originally Posted by SlideWise

My question is there any reason i should tear back into it and remover the upper right timing guide as well or should it be fine since its not making noise any more?

IMO its one of those things where your already there and its just like 6 more bolt that you have to remove to remove the top timing chain cover, and a couple of bolts for the right side timing chain guide. Just make sure if you do decied to remove the cover to set the #1 cyl. to top dead center and the distributer is firing on the #1 cyl. I dont know if you can see the tik marks on the crank pully with the belts on but once you have the first two things in place make sure the timing pin/stud in on the 2nd notch on the pully and your good. Only question now is, since you have already put it back together, is your time, a new valve cover gasket kit, and a tube of rtv silicone worth the noise the guide may make?

[SPECIALTURD]

Yup my s14 has been sitting in storage for 5 years and makes that noise. At first i thought it was the fan clutch or a valve but since reading this thread its for sure the valve guides.