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[bexandpower]

How to tell the difference from a compression test wether there is a valve fault or a piston ring fault? is there a way to find out which is at fault???

[Nickbat]

Hmm, I was always led to believe that a stuffed piston ring would force oil into the cylinder which would burn with the mixture and  cause blue smoke to be emitted out of the exhaust.

Mark's yer man though. As soon as he sees this thread, he'll give you a definitive answer.

[bexandpower]

Cool cool. So therefore the valve being bent may not cause any emission problems.

[Marks DTM Calib]

Valve damage will cause a close to zero compression reading.....a failed ring normaly hardly changes the compression (might lower it a bit if bad) but does show up more on a leak down test (there are two compression rings and an oil control ring)

[bexandpower]

Valve damage will cause a close to zero compression reading.....a failed ring normaly hardly changes the compression (might lower it a bit if bad) but does show up more on a leak down test (there are two compression rings and an oil control ring)

I am going to try and get it compression tested again tomorrow ill find out what the results are then. Do you think a valve problem could be what is causing the engine trouble? (described in my other thread http://www.omegaowners.com/forum/YaBB.pl?num=1164823056/0)

[sir moanalot]

hi, in the old days i heard of a "wet test" to help seal the piston rings -if the compression test was poor then it diagnosed a valve, if the test was good it was the piston rings as they were "sealed" by the fluid. how much you put in is minimal it just has to cover the ring seal, best seek further advised on it from someone whos done it. tone

[Marks DTM Calib]

It doesn't real work on modern cars very well due to the pocketed pistons and the central position of the spark plug hole in the bore (this is where you add the oil/fluid)

[rogerreno]

After reading back through your original post in my opinion as a technician (without seeing the car but going on the symptoms you've given) I would say that its very likely that one or more of the valves has made contact with the piston due to the belt slipping.
As i'm unfamiliar with these engines due I take it they've got hydraulic tappets?? If you've got a bent valve this will give you the tappet noise,due to the top of the valve sitting further down in the head and the hydraulic lifter unable to close the larger gap. May pay to check valves on number one cylinder for extra clearance as hydraulic lifters don't usually have a clearance like manual adjusters.

You say that the compression on number one cylinder was 'a little low' How low are we talking in relation to the other 5 cylinders because a small difference would very rarely give a noticeable running problem.

If it was a piston ring (compression ring) fault you would be getting excessive crankcase pressure (breathing heavy when the oil filler cap and/or dipstick is removed) and zero compression.

Or if it was an oil control ring fault you'd have a noticeable oil consumption problem (accompanied with blue smoke) and the spark plug on the affected cylinder would be contaminated with oil.

I think they've realised they dropped a bollock and are hoping that by slipping into bullsh*t mode (how many times have I heard it in the workshop!!) they're going to be able to able to fob you off.

All said and done I would have thought that if they were a reputable garage their labour/work should be covered by a 12 month warranty.  :question

If they've screwed it up,then its down to them to fix it F.O.C and not for you to pay out more money  

Hope you get it sorted (keep us posted)

Cheers

Roj

[bexandpower]

Took the car for an independant compression test and evaluation today seems like piston 1 is running about 60% lower thant the rest (all others about 150psi this one abour 5o!!!!).  So do you guys reckon that valves are knackered??? given the history both myself and the mech that did the tes were inclined to say yes.

[theolodian]

Took the car for an independant compression test and evaluation today seems like piston 1 is running about 60% lower thant the rest (all others about 150psi this one abour 5o!!!!).  So do you guys reckon that valves are knackered??? given the history both myself and the mech that did the tes were inclined to say yes.

Don't know the history, but sounds like valves or seats.  If doing the work myself, I would pull the head.  If paying someone else to do it, would get used engine if car worth it.  That way u don't waste money if not valves.

[bexandpower]

Took the car for an independant compression test and evaluation today seems like piston 1 is running about 60% lower thant the rest (all others about 150psi this one abour 5o!!!!).  So do you guys reckon that valves are knackered??? given the history both myself and the mech that did the tes were inclined to say yes.

Don't know the history, but sounds like valves or seats.  If doing the work myself, I would pull the head.  If paying someone else to do it, would get used engine if car worth it.  That way u don't waste money if not valves.

I have done previous threads on the history of what has happened so far the links are

http://www.omegaowners.com/forum/YaBB.pl?num=1164823056/0
http://217.155.56.220/forum/YaBB.pl?num=1164216979/0

I shouldnt have to pay for the work to be done on it but i dont want to get stumped with a huge bill if it isnt something to do with the cam belt slipping. Aghhhh dilemma dilemma