Compression In A Turbo Engine?

[pablo 0]

Hi all, long time no post but have recently bought a 205 gti with the 406 sri turbo engine fitted.

 

Drove it home from East Midlands to Belfast and noticed it had used a bit of oil (1/2 litre roughly). So I feared the worst and done a compression test there.

 

All readings were 145psi ish. The last cyclinder (closest to the timing belt) took a couple of goes to reach 145. I dont know if I just hadnt cranked long enough or if its a sign of a problem. I reset the gauge each time so I guess that would have released any pressure there already. Not an expert on this by any means.

 

Engine recently had a turbo rebuild, and I cant see any signs of leakage. Id swear I smelled a little bit of burning oil at one point too but not since.

 

Any help appreciated.

 

Oh and lastly what oil should I be using to top up with?

 

Cheers all.

-Paul

[24seven 104]

roughly how many miles was that drive? .5L is a bit much, but those compression figures don't seem desperately low, maybe a little. If it's not leaking from around the engine (check the sump plug & around its seal, also check the oil filler hose for wear/cracking) then it could be the valve stem seals wearing out. Does it smoke at all from cold?

[pablo 0]

cheers, about 350 miles altogether. whats a healthy figure on a turbo engine?

[24seven 104]

I don't know the quoted figures for the engine in question, but generally for 2.0 turbo you're looking for around 150 - 160ish when new so 145 isn't bad, more so because it's even across the cylinders, but yeah half a litre of oil over 350 miles is a fair bit, I'd check for leaks. If it's had a turbo rebuild it may be an oil feed to that, which would explain the burning oil smell.

[pablo 0]

only got home on monday there (picked up some food poisoning on the trip too) so not had a good look around but doesnt seem to be any leaks from around the turbo. ill need to strip the pipework away to get a good look.

[pee vee 1]

its probably the actual turbo to be honest mate.

if you coast down a hill, using the engine as a brake, then rev it at the after, is there any/much blue smoke out the back?

turbo seals going causes this.

 

on a turbo engine, if the rings are worn its quite possible it would start breathing heavy.

[pablo 0]

turbo was rebuilt by turbo technics a few hundred miles ago apparantly. Do the seals need to bed in or anything silly?

 

Havent seen a puff of smoke at all and was fairly pushing it across scotland.

[jonnyturbo 3]

mines smoking on idle quiet alot and iv put it down to the stepper seal which is causing it to leak oil in to the cylinders or manifold, not quiet sure which or if either are correct, just going on what iv been told.

[pablo 0]

had a look underneath the car yesterday and could see oil on the rear cross section of the subframe (I assume it was a subframe anyway) so looks like I have a leak. Which is much more preferable to a set of knackered rings I guess.

 

Hopefully its just the oil return pipe from the turbo split or something. Fingers crossed!

[pablo 0]

Right, had a better look there and still none the wiser. I can see oil over the top and bottom of the lower mount, around the subframe side and back, and around the back of the sump etc. All on the drivers side under the turbo. Oil return pipe was dirty but not exactly swimming in oil and there was nothing visible around the back of the block or underside of the turbo.

 

I can also smell it burning when I gun it a little on the driveway. But cant see any oil around the manifold or downpipe.

 

very puzzling.