New style chain guide failure

[Q45tech]

While resealing the valve covers on a 93Q [160k] we noticed a piece of black plastic in the upper right head upon examination it was the curled over top piece of a tension side guide which had broken free.We changed out all the guides and tensioners [and oil chain] just to be sure [so no more pieces might separate and end up in the oil pan].

Probably a good idea to examine even the new style guides at 150k just to be sure - applies to 93-96.Never seen this before as the few we examine have always been ok but we don't look at many.

[911/Q45]

Boy, this is just what I wanted to hear!

[Q45tech]

It costs less than changing the timing belt on an LS400 every 90,000 miles. Hey it takes only 4-5 hours to look

Not looking for more problems [or revenue] but every engine made in the world should be opened for inspection once every 120-150,000 miles.

Now that mine passed the oil pressure test, I have to evaluate how the last 139,000 miles have treated the replacement guides [@100k], maybe I'll wait for the plug change at 260k and the leak down test to decide if its worth it.As little as I am driving today [12k per year] the end is a long way off.....will it last another 5 years and 300k?

[Chally]

Thanks for the warning. I must seal my covers soon.

[Q451990]

While resealing the valve covers on a 93Q [160k] we noticed a piece of black plastic in the upper right head upon examination it was the curled over top piece of a tension side guide which had broken free.

I thought the old guides were for 90-93 model years... are you talking about a 94 model year built in 1993? In any case the guides you took out were the plastic coated metal backed guides like the 94-96 engines got from the factory?

In any case this is sure not good news... I guess no design that involves a chain rubbing something is bulletproof.

Heath

[Q45tech]

We had no history other than the 93Q had the new design metal backed guides and this [tension side guide] is one that never fails on the old style. Even if it fails [in the manner it did] very unlikely to derail the chain. We were only concerned with making sure we had the only piece.........all the others looked good with wear appropriate for 160k.

[Q451990]

That's very interesting... I was always under the impression that the new guides came along at the same time as the grille. That's got to be good news for everyone out there with the 1993 model year! Sounds like that's the car to have - old gearing, new guides, first gear start... was the steering ratio different on that year?

Heath

[PalmerWMD]

heath:

not nearly all of the 93's have the new style guides.Generally a very late production 93 is considered reasonably safe.But all others need to be opened up and checked.

Fred...