Good morning,Advice from senior members

A leak down test and or a compression test
ILL see if I can find a step by step link.

leak down link
en.wikipedia.org/wiki/Leak-down_tester

www.motorcycleproject.com/motorcycle/text/leakdown.html

denhamfly;6211 wrote: gas chromatographs

REALLY?! What the hell for?! I have used them many times, but never worked on one!

denhamfly;6211 wrote: This car has always kicked my ass. I am not a hundred percent sure it is the valves yet. It was doing this years ago and it was, because of a disc on the flywheel that was slipping that made it impossible to time. Have you ever heard of that problem before? Ether one of the above problems are a pain, I just need to get off of my behind and figure out which one. Is there an easy way to diagnose bent valves?

Look at the belt via one of the peep holes in the TB covers. That will tell you whether the belt broke which would almost certainly result in bent valves.

denhamfly;6211 wrote: because of a disc on the flywheel that was slipping that made it impossible to time. Have you ever heard of that problem before?

As I recall there is a sensor near the top of the flywheel cover that senses a wider gap in the flywheel for timing purposes. I can't think of a "disc" that could slip to cause an issue, but I certainly don't know everything. The sensors are a common failure part, due to age as I understand.

Brad's suggestion on checking under the timing covers is a good one. I would suggest removing the passenger side cover to review the timing belt tension as well, since technically it could remain intact but still slip a tooth or two and result in bent valves as well. As Brad suggested usually it is a complete failure of the belt that causes the valves to bend, often because of the water pump bearing failure.

I am definitely a fan of Ed's replacement water pump that includes a larger bearing but also isolates a bearing failure from the timing belt, so a water pump failure is just that, not also a bent valve issue.

Stan, like you, I can't make sense out of the slipping flywheel symptom either. :confused:

Perhaps the portion of the flywheel that the CPS (Crankshaft Position Sensor) picks up on was damaged or broken off.

KilnRed;6231 wrote: Stan, like you, I can't make sense out of the slipping flywheel symptom either. :confused:

Perhaps the portion of the flywheel that the CPS (Crankshaft Position Sensor) picks up on was damaged or broken off.

I actually probably should have said "timing ring" as I think it is better known as that. The timing ring is only pressure fit to the flywheel as I recall, and can be removed if needed. It just wouldn't seem terribly likely that it would slip.

I had my '90 GT converted from the single disc clutch to the older, and stronger, dual disc clutch. Swapping the timing rings from an S4 automatic to the S flywheel was part of the process, so I do know they can be changed.

As I recall the process of swapping timing rings is usually performed by heat and cold.

Wow, the thought just occurred to me, I wonder if any of my car symptoms could be related to a slipping timing ring. My first thought is that timing would show up as wrong, since a slipped timing ring would cause the plug to fire when the piston was in the wrong position....