hn

This thread is interesting, sort of confirms what my mechanic told me, he's only replaced lifters on one 993 so far.

Dan V

when the ticking stops is when you should worry

*tick*
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BOOM

Droops83

Good point to bring up, and exhaust leak will often make a similar sound, takes a bit of a trained ear to tell the difference. A ticking due to valvetrain noise will increase in frequency when the engine is revved, while an exhaust leak is more audible at idle and will be muted when the throttle is snapped open. Backfiring can also accompany exhaust leaks. Also, lifter/rocker noise will be more of a "sharp" ticking compared to an exhaust leak or injector noise.

Also, somebody had a good point as well when they pointed out that all aircooled engines are noisy---this is true. There are no water jackets to muffle all the clatter going on inside, which I like! Porsche tried to make the old aircooled engine a bit more refined for the 964/993 series, with the quieter cooling fans and sound trays on both (also to meet noise regs) and the hydraulic lifters on the 993 (also for easier maintainance). But a bad lifter on a 993 will make a pretty audible ticking sound which is not normal. We have only done the lifters on a few 993s since I've worked at my shop, and each time it fixed the problem. It is a good idea to check rocker arms and valve guides while you're in there replacing lifters.

---

Chris Andropoulos
Schneider Autohaus
Santa Barbara, CA

IXLR8

Good point, but how do you know what the part numbers are of the lifters that are installed? I've been told by another RLer that the lifters have no markings.

Also, when buying new lifters, how do you confirm which ones you got, other than the part number on the packaging, which could have been labelled incorrectly.

Actual lifter lengths which Porsche does not list in PET or the Repair Manual would be more useful.

The only data I came up with from a Euro site is a length of 25.8 mm for the standard lifter.

Holytin

I don't mean to scare the crap out of you but last time my engine started ticking the well known valve guides had been identified as the root cause for the noise. It really is the worst case but still a possibility...

IXLR8

Not concerned in my case with my very low mileage and cooler operating temperatures up here.

Another RLer got me asking the question after he installed new lifters.

So how do you know what length lifters are installed? -0.5 mm and -1.0 mm is relative.