[Mk2] [Turbo] Engine stripped and problem located

[Andy Jones]

Well folks after a couple of weekends and lots of stress/swearing/cuts/swearing/getting caked in oil/swearing/rounding off a stupid bloody sump bolt hidden inside the flywheel housing and a lot more swearing the damage was confirmed:







Wasn't quite expecting to find the piston in the state it was in but i'm glad i took it off the road when i did. No scoring at all to the bore which was a pleasant surprise but we did find a tiny crack in the cylinder head so thats going to have to be sent away to be tested before it goes back together.

[JJ]

Hey andy,

What were the symptoms again ??

Smokey, down on power, compression down on one ?

Well done locating it !

[Andy Jones]

Hi JJ,

No loss of power but oil started exiting via the dump valve and Steve Horrocks did a compression test on it which revealed number 4 was down 50psi.

Just relieved now it's all apart and we did find something (once the head came off and we saw no damage to the bore on the suspect piston the back of my mind was saying please don't say it's something else and all that was for nothing) Thanks again for the info you supplied via PM and to Steve Horrocks who's worked his socks off helping these last couple of Sundays

[Steve Horrocks]

No worries boss, jus sorry it's a bit cream crackered matey!

[Ian Geary]

Hi Andy

I had this too - no loss of power, but loads of oil loss and zero compression in 4 (the ringland had broken up)

Have you got any thoughts on the cause though?

Whilst I replaced pistons, i see quite a few ringland failures (both here and on GT4 forums) but most people focus on fixing the symptom rather than the underlying cause.

Ian

[Steve Horrocks]

As he mentioned in the other thread, 1.4 - 1.5 bar, stock ones don't like it!

[Ian Geary]

oh, ok

didn't see the other thread. mine was on stock boost though...

hey ho

Ian

[Andy Jones]

Hi Ian,

As Steve mentioned, Running naughty boost so was only a matter of time i guess, What miles had your engine done on stock boost for the ringland to fail (having spoken to JJ about this before he'd said 1.4bar is asking for trouble on stock pistons) and did you have any idea what caused it? Mine was coming up to 88k and it did develop a misfire on boost a few months ago although i stopped driving it hard and just used it to get to work and back so perhaps "putting off" the plug change helped seal it's fate?

I did eventually change the plugs and boost went back to normal but 2 weeks later all the oil problems started

[sutton]

Oh noo, this is exactly the same as mine ive got so much oil coming out of my dump valve, i'll have to take it too luke at pacific works and get him to investigate

[Andy Jones]

Oh noo, this is exactly the same as mine ive got so much oil coming out of my dump valve, i'll have to take it too luke at pacific works and get him to investigate

Not good mate I'll pass on what i was told, Stop driving it and get a compression test done. Off boost there was no sign anything was wrong with it but then mine started leaving small oil patches in the garage and at work.

[sutton]

cheers mate, werloss i havent seen oil patches on the floor yet though, just loads on my fan cover and my dump valve is covered.

[Steve Horrocks]

chris, have a compression test done first, it may just be turbo oilseals matey (Andy's seems o be both seals and the obvious pistons!

[sutton]

yea im getting one done tomorrow night mate, ill keep you updated!

[diycinema]

Hi Andy

I had this too - no loss of power, but loads of oil loss and zero compression in 4 (the ringland had broken up)

Have you got any thoughts on the cause though?

Whilst I replaced pistons, i see quite a few ringland failures (both here and on GT4 forums) but most people focus on fixing the symptom rather than the underlying cause.

Ian

Me too! 3 cracked ringlands, oil shooting out the BOV.

I reckon knocking caused the damage on mine, i couldn't see any signs of going lean. Previous owner was running an MBC, probably got a bit excited at some stage.

I hooked up a coke bottle to the PCV outlet, it filled up with oil almost immediately suggesting pressured crank case. I also did compression check, only failed on one cylinder. Turbo was fine, rebuilt it anyway. Panel filter had caused wear on the compression wheel so replaced that as well.

[sutton]

Well had a compression test done, cylinder 3 is down and suspected piston rings! time for my power goals to be reached