So.. my car has a hair over 15K miles on it, and I'm about to have to replace the timing chain tensioner for the 2nd time (the first time was around 10-11k miles, IIRC).

My car has had a bit of head work done to it (head was milled slightly), and it is also only used on weekends (driven maybe once or twice a month). I'm just curious if either of these factors has played a role in the tensioner failing (not sure how they would... but whatever), so I thought I'd find out what others' experiences were.

I just can't believe that I'm having to replace a $100 part for the 2nd time in less than 8000 miles.

 

Wow, that is odd. Sorry that is all I can offer.

 

Here is my opinion of what's happening with the chain tensioner and my solution to the problem. Note: I am not recommending this solution, I only stating that this is how I corrected the problem on my engine.

- I think that when the timing chain stretches and the tensioner is extended from the original position the large spring in the tensioner does not have enough force to hold the guide tightly against the chain until oil fills the cavity in the tensioner valve/plunger. As the engine oil pressure rises, at start up, the force of the plunger is added to the spring force and applies sufficient tension to the chain guide. The oil "bleeds" out of the plunger as the car sits there, with the engine off and the whole thing starts over again. A thicker/higher viscosity oil would reduce the "bleed down" time.

- My solution was to stretch the large spring in the chain tensioner by approximately 1/4". Since I did this I have not had and timing chain/chain guide noises at startup.


I'd be interested in knowing if the problem is more prevelant on hot days/high temp. environments (SoCal. AZ, etc.) than in low temp. environments (Canada, Alaska, etc.).

Whenever you shave the cylinder head, it acts as though the chain has more slack and the chain tensioner must extend out past the original position. So, shaving the head is the same as having a loose chain/high mileage.

My head has been cut 0.065" (a whole lot) and my block has been cut ~0.010", so the problem was much worst on my engine than most others.

 

Greenlight-

Thanks for the useful post. I think I'll look around and see if I still have my old tensioner... I might try "stretching" the spring like you did and re-installing it.

Just FYI.. I am in Dallas (a warm environment), and if memory serves me correctly, I've noticed this issue most when the engine is warm and temps are warm. I don't have the "startup rattle" that some people have described, I only have the "card in bicycle spokes" sound when the engine is warm... and noticed it was particularly bad one time after a summer autocross.

 

FYI.

My car has 73K and is 4.5 years old. The short block was replaced at about 15K but the head was not. It was replace due to hydrolock.

 

yeah, have had that same noise for the past couple months, its only at start up, and fades away as the rpms rise. have a new one waiting for me, and really looking forward to replacing it! my s has 38k about to roll to 39k, started hearing it at around 35k.

 

[QUOTE=mxt_77,Jun 19 2006, 10:25 AM]My car has had a bit of head work done to it (head was milled slightly), and it is also only used on weekends (driven maybe once or twice a month).

 

I over-reved on track and on the way home developed a tapping sound...thought I had cracked a retainer. But after pulling the valve cover and doing a thorough inspection, that was not the case so I just adjust a couple of tight exhaust clearances... noise still there tho. 83K on the odo.

I replaced the cam chain tensioner, all the odd lil noises go away, AND the car FEELS stronger...possible timing advance that the tensioner was not allowing

 

The timing chain tensioner adds tension to the "slack" side of the chain, so this would not alter the camshaft timing. It just keeps the slack side from bouncing around.

However, as the timing chain "stretches" during the course of normal wear the cam timing does retard. As a general rule, when you retard the cam timing you gain high rpm HP and lose low rpm HP.

Regarding the stretched spring not being a lasting solution, when you stretch the spring you are actually yielding the material and that is a permanent defromation. When the spring is compressed/heat cycled, etc. it will NOT yield and become shorter than the "stretched" length. In summary, the fix is permanent.

 

Originally, after an autocross I heard a sound coming from the engine bay that sounded like a card in bicycle spokes. Since I had previously had a set of Toda camshafts grenade in my engine, and I was running a 2nd set at the time I heard this noise, I feared that this 2nd set had failed, too. So, I pulled the valve cover off and the camshafts were still in good condition. I checked valve clearances, and they were still spot-on.

So, the car cooled off, and I cranked it up and the sound was gone. I drove it home, and found that I could get the slightest flutter just off idle. I used a poor-man's automotive stethoscope to narrow down the origin of the sound to the tensioner (which I noted as, "that little thing below the VTEC solenoid" at the time). Ordered a new one, replaced it, and the sound was gone... at least for another few thousand miles.


Regarding the warranty... even though the car only has 15K miles on it, it has surpassed the 3 year term of the warranty. Plus, I suspect they'd claim that I voided my warranty when I installed the cams & had the headwork done.