One cylinder compression way down. What next?
09-06-2017, 04:38 PM
#17
more details please.
What was the leakdown in cyl 3? And from what I'm interpreting, the cyl is leaking out the exhaust valve? Most likely your valve guides are shot and that valve is just not sealing any more. I guess you could take the valve cover off and have your shop remove the valve spring and do some measurements on the valve play, but with 74k miles and some track work, I'd bet at least one, if not more of your valve guides need to be replaced.
Rest of the motor is likely fine. So you're probably looking at top end rebuild and some odds and ends.
What was the leakdown in cyl 3? And from what I'm interpreting, the cyl is leaking out the exhaust valve? Most likely your valve guides are shot and that valve is just not sealing any more. I guess you could take the valve cover off and have your shop remove the valve spring and do some measurements on the valve play, but with 74k miles and some track work, I'd bet at least one, if not more of your valve guides need to be replaced.
Rest of the motor is likely fine. So you're probably looking at top end rebuild and some odds and ends.
The least you can do for knowing everything and everyone.
Last edited by Rockit; 09-06-2017 at 04:58 PM.
09-06-2017, 05:32 PM
#18
Race Director
Perhaps then, you can share, from your infinite experience, what is different about the 95 that makes it "easier on the valves" Seemingly the 95s don't have valve guide issues according to you?
09-07-2017, 02:28 AM
#22
Rennlist Member
Pull the lower valve cover and pull the #3 exhaust rocker off. Try leakwod again. Tap valve stem while doing leak down. This should help the valve seat if it's a carbon problem.
Don't panic just yet.
Don't panic just yet.
09-07-2017, 08:09 AM
#23
Race Director
Woah, 20% leakdown in most cylinders is bad, with 70% in the other a real issue. its possible your shop screwed up but if these numbers are legit its no surprise your car is down on power
09-07-2017, 09:57 AM
#24
Drifting
09-07-2017, 12:58 PM
#25
Race Car
The shop should have provided you with the leakdown along with where the leak was coming through. Any competent mechanic will listen to hear where the "Leak" is coming from. (exhaust for exhaust valves etc) You can also hear it from the oil tank if it is the rings that are the problem.
With one cylinder at 70% I would suspect that you have broken a valve spring, something is jammed in the valve or that the valve has some form of damage.
09-07-2017, 01:45 PM
#26
Rennlist Member
"The shop should have provided you with the leakdown along with where the leak was coming through. Any competent mechanic will listen to hear where the "Leak" is coming from. (exhaust for exhaust valves etc) You can also hear it from the oil tank if it is the rings that are the problem."
....Which would give me serious concern that this shop just might not have the attention to detail required to perform the needed repairs.
....Which would give me serious concern that this shop just might not have the attention to detail required to perform the needed repairs.
09-07-2017, 02:01 PM
#27
Rennlist Member
+1
There are a lot of competent shops in the NYC area. The information provided by the shop don't inspire much confidence in their skills or maybe they just want to push for a rebuild without doing proper due diligence.
Either way, not a place where I would leave my car much longer.
There are a lot of competent shops in the NYC area. The information provided by the shop don't inspire much confidence in their skills or maybe they just want to push for a rebuild without doing proper due diligence.
Either way, not a place where I would leave my car much longer.
09-07-2017, 02:47 PM
#29
It sounds to me like the shop is pushing for a rebuild without giving you all the information that is needed.
I'd get a second opinion at a good reliable Indie shop!
09-07-2017, 05:28 PM
#30
Nordschleife Master
Find another shop first. I never find a motor, especially a 993, that has 20% leakdown across the board. 5 of the six cylinders will still be under 10% unless issue like you have. As mention easy to pull manifold and valve cover.