Off with the head, or engine out ????

[bob gray]

Hi all
I have a problem with the car burning oil in quantity ! when driven hard,I found a lot of oil in the intercooler so first thought is the turbo (right ). It has apparently been fitted quite recently. When I bought the car Ian said there may be some oil still in the intercooler
when the turbo went, I however cleaned out the pipes and intercooler. Further investigations revealed oil in the plenum chamber and the hose to the turbo inlet was also oily. ( I am assuming this could only come from the engine breather ) I did a compession test and all except no 4 were about 125 psi no 4 just about made 40psi. I would like the advice ,, is it best to remove just the head and investigate or bearing in mind the symtoms remove the complete engine and rebuild ??First senario is cracked head ?? worst is holed piston or bore fcuked.I was intending to take the car out for the winter and do a little bit of bodywork repair What would you advise

Bob

[SteveT63]

Which engine?
Transverse? Long?....Sounds like rings on 4 to me.

[john johnson]

It's gordons old car Stephanie

[Phil Payne]

Originally Posted by bob gray

I have a problem with the car burning oil in quantity ! when driven hard,I found a lot of oil in the intercooler so first thought is the turbo (right ). It has apparently been fitted quite recently. When I bought the car Ian said there may be some oil still in the intercooler.
When the turbo went, I however cleaned out the pipes and intercooler. Further investigations revealed oil in the plenum chamber and the hose to the turbo inlet was also oily.

If you're new to these engines, it's AMAZING how much 'oil' you will find in the intercooler and inlet hoses. It's actually breather condensate, and it's not unusual to have to watch your feet when taking hoses off.

Originally Posted by bob gray

I did a compression test and all except no 4 were about 125 psi no 4 just about made 40psi. I would like the advice ,, is it best to remove just the head and investigate or bearing in mind the symtoms remove the complete engine and rebuild ??

The world plus dog has been telling me this engine has already been rebuilt. I've offered to check it over for expenses only six times and never had a response.

Originally Posted by bob gray

First senario is cracked head ?? worst is holed piston or bore fcuked.I was intending to take the car out for the winter and do a little bit of bodywork repair What would you advise

A cracked head almost always produces so much white smoke you won't see out of the back. A holed piston produces wonderful (and unmistakable!) symptoms in the breather system - you have to see it to believe it and the car doesn't run very far. Bore damage will cause the oil loss, but not the compression problem and is in any case pretty rare - it's usually caused by ingestion.

Knowing how the car used to be driven, and speculating a little, I'd suggest pulling #4 piston (head and sump off) and checking both the rings and the spray jet. I suspect the oil control ring (at least) has crumbled.

[Phil Payne]

Originally Posted by john johnson

It's gordons old car Stephanie

ROF,L!!!!

HOOT!!!!

The "fully restored" one?

Who did the work?

[john johnson]

Not you , your reputation preceded you according to the previous owners , something to do with being a meddlesome pisshead

[Phil Payne]

Originally Posted by john johnson

Not you , your reputation preceded you according to the previous owners , something to do with being a meddlesome pisshead

Well, the previous owner was Ian. I presume he (like me) attended Gordon's funeral but I don't remember any in-depth discussion. Perhaps he got that impression from someone else.

[john johnson]

He did indeed and not me

[20vcqdriver]

Was it number 4 that had the problem before? If piston and rings were replaced was bore honed first or possible ring damage during fitting if tops of bores not cleaned up first. Mine need doing as look like this at moment...

[Phil Payne]

Originally Posted by 20vcqdriver

Was it number 4 that had the problem before?

I remain unconvinced that this engine has ever been apart - that's what I'd like to check. There's something very fishy here.

Originally Posted by 20vcqdriver

If piston and rings were replaced was bore honed first or possible ring damage during fitting if tops of bores not cleaned up first.

Genuine Mahle replacement rings are slightly chamfered so that they don't - in theory - impact the lip at the top of the bore. The top ring is a few mm down so it doesn't sweep the entire bore - you get a lip both because there's no wear at the extreme top and also because combustion products react with the unswept bore surface.

But that's the theory. If you swap the big end shells you change the swept length of the bore and you may bring even a chamfered ring into contact with the lip. Gordon's engine was subjected to extreme wear and I would expect it to be right on these limits.

I would also expect (from the way he ragged it from cold) that the bores are to some degree oval - WR pistons are oval when cold and cause transverse wear at the bottom of the bores.

And on top of all of that - if it HAS been rebuilt after a problem in #4, I would assume that the oil spray jet - 035 103 157B - in that cylinder has been replaced and I'd expect to see that (they're not exactly cheap) on the invoice for parts.