jimcabc

The recent spate of questions about valve guide wear has me wondering. I've got a 1987 911 Carrera with close to 40k miles on it. I've put about 8k miles on it since purchase 3 years ago. It appeared to be well cared for by po(s). It uses virtually no oil as far as I can tell, between yearly 2+k oil changes.

Question is what are the probabilities of having shot valve guides in the 60+k mile future? 5%?, 10%?, 20%? 50%? Just how common is this problem, and are there predisposing factors? I'd appreciate opinions from any experts/service techs & those with experience. Thanks!

Jim
'87 911 Cabrio
blk/blk/blk

Marty916

From what I understand, the premature guide wear is caused mainly by the valve guide seals. The original seals are rubber and don't allow sufficient lubrication for the guides and valve stems. I recently had my guides go bad on my 87 Carrera. This happened at 34k miles and I take exception care of the car maintenance-wise. The shop that did the repairs backdated the guide seals to an earlier version. This seems to be the common fix for this issue. There may be other factors involved that some of the more experienced folks here could expand on.

fixnprsh

mine lasted 180K just do the oil changes as there are acidic properties that gather in oil as a byproduct of combustion, if you dont change it regularly enough, these acids attack seals and cause leaks. the valve guides are crap but live with regular maintaince, if you have to change them go with better guides (I.E. not factory) I cant belive the factory pushed 15K mile services in these cars, its rediculous! just like the 996's I reccomend 5K between synthetic and 3500 between regular oil changes.

88911coupe

Another big factor is that the valve guide material is too soft. I think this has as much to do with the problem as anything. Later material valve guides apparently run MUCH longer without wear.