[A26B]

Originally Posted by Dynomite

One Maintenance item I think about is the Chain Guides wear (and only the two chain guides pushed by the Tensioners). There have been a couple instances (only 2 that I am aware of) of timing chain failure or chain guide failure (still have no clue on what caused the Timing Chain Failures).

Jerry.....what is now your best estimate on Timing Chain guide longevity and replacement?
(I know it depends on Engine Oil and Engine Oil Maintenance for example)

We need to differentiate between the guide & guide facing. Guides, for all practical purpose, don't wear out or break. Insofar as the guide facings, I have enough facings to last another 395 years, based on sales average over the last 5 years. Or, I have 1,975 sets in stock & you can do you own math.

FWIW, I have a good inventory of both new & used guides & there are always used guides available, due primarily to the lack of need.

Guide Facing Longevity: Hard question to answer with so little sales volume to work from. Considering 23+ years of age on less than 7000 ZR-1's, I would say a very long time. I would guess most of my sales are because of the "while I'm in there" syndrome, which I endorse. I've heard of a couple of broken pivot guide facings over the years. However, if guide facings follow the trend of other parts, once they begin to fail in ernest, the frequency of failure will increase, like the fuel pressure regulator.

Timing Chain Failure Causes: A couple that I know of failed due to other parts failing & ultimately damaging the chain; cam cover chain guide screws coming loose (didn't remove before powder coating) This is another part that is done "while I'm in there." I don't get to see a lot of sprockets to judge wear, but only rarely do I ever sell any of the chain sprockets. Worn sprockets usually accompany worn chains.

IWIS manufactures Secondary Timing Chains for us now. I have no concern that they will not be available for the forseeable future. IWIS is a major supplier for cam chains for European automobiles. IWIS chains are pre-stressed to seat the links & pins, just like the OE chains are. They have a slightly heavier side bar and still fit the OEM sprockets perfectly. We have had them installed in 2 3 exotic LT5 racing engines, turning upwards of 8500 rpm. in racing events.