Evening All

 

I finally got around to doing a compression test on my TT today, 11 years old but doesn't use any oil at all, runs very well and totally smokeless on start up or otherwise. Anyway, on a warm engine cylinders 1,2,3,5 = 120psi 4,6=110psi. I wasn't looking for a particular problem, just doing a check. From a search on here though I see that is below manufacturer specs, although they are all close. Do you think this is more likely to be through using a 16 year old gauge?? :-) If the pistons / rings were all that worn uniformly wouldn't I have oil consumption problems as well? :(

Standard is 186-142 (I think) and there should be no more than 14 psi difference between the cylinders.

 

The gauge is probably a little bit out, but not much. Good quality tools dont tend to get that inaccurate over time.

 

All cyinders are down, but they are all down together. The engine is a little worn, but least its wearing down even.

 

Nothing a set of over sized rings wont cure. :D :D

Was it a wet or dry test ?

150 or therabouts is a good healthy engine

 

120 is worn but not drastic if figures like 70-100 were shown then id be more worried!

Ok thanks. It was a dry test, but on a warm engine... I'm gonna check the gauge though, as another car I tested (a Volvo) also had quite low figures but again all even. So, to fix this properly and if I was flush with cash (which I'm not!), what are we looking at? Engine out, hone and new pistons/rings? A re-bore? New liners?

Ok thanks. It was a dry test, but on a warm engine... I'm gonna check the gauge though, as another car I tested (a Volvo) also had quite low figures but again all even. So, to fix this properly and if I was flush with cash (which I'm not!), what are we looking at? Engine out, hone and new pistons/rings? A re-bore? New liners?

 

 

all depends on what damage if any is present!

 

obviously engine out LOL but if piston rings are damaged they can sometimes damage the block aswell so as you say a new liner would need to be used,TBH without engine out who can say! Broken rings can have a knock on effect and also damage the piston itself then the cylinder so without stripping who knows!

 

why did you do a commpression test anyhow performance down,smokey engine etc

If it ain't broke, don't fix it ! ;)

If it ain't broke, don't fix it ! ;)

 

Yes I agree... I wasn't about to rip it appart! :shock: The car isn't a daily driver, there's nothing wrong with it but I wanted to know where the compressions were as a general indication of the wear. There's no oil consumption or smoke at all. I've done a lot of work and mods on the car, Greddy boost control, ecu, new coilovers etc etc But I've never driven another z with 1 bar of boost so I have nothing to compare it with. Spose the thing is to get it on a rolling road sometime and see how it fares, then at least I'd have an idea of where it is in the performance stakes. If it's down in a big way then I'll look at taking the lump out and rebuilding it, and doing some major mods at the same time. Any suggestions for somewhere to take it for a rolling road check? Someone who knows our cars well? What about Z tech (no rush, I know they're busy...)

If you're still worried then try a wet test. After that it's a rolling road test. I know of a couple of places around the Essex area, I'll dig out their names if that's close enough for you.

Thanks. Think I'd like to put it on a rolling road sometime anyway. If I find it's only producing 300bhp at the wheels with 1 bar of boost then it's coming appart! :mad:

Yes I agree... I wasn't about to rip it appart! :shock: The car isn't a daily driver, there's nothing wrong with it but I wanted to know where the compressions were as a general indication of the wear. There's no oil consumption or smoke at all. I've done a lot of work and mods on the car, Greddy boost control, ecu, new coilovers etc etc But I've never driven another z with 1 bar of boost so I have nothing to compare it with. Spose the thing is to get it on a rolling road sometime and see how it fares, then at least I'd have an idea of where it is in the performance stakes. If it's down in a big way then I'll look at taking the lump out and rebuilding it, and doing some major mods at the same time. Any suggestions for somewhere to take it for a rolling road check? Someone who knows our cars well? What about Z tech (no rush, I know they're busy...)

 

z tech wont be as busy in september so could always give ryan a ring

z tech wont be as busy in september so could always give ryan a ring

Ehhh Sept is now fully booked Oct is looking okay though :(