Have I destroyed my engine?

[DJButler]

Not correct.

 

That's Really Helpful..........

[b_have]

8.5 is the compression ratio (max and min volumes within cylinder/head) Pumping pressure should be around 160~180 psi dependant on quality of guage,wet or dry,hot or cold,cranking speed etc.

More important is the consistancy between cylinders, tiptop fresh engine should be within2% but 10% is workable on an older engine.

[b_have]

That's Really Helpful..........

 

Too pissed to type

[Chris Wilson]

If you've got it seriously hot the rings will have lost their tension. Full engine strip, hone or rebore, and new pistons and rings. Having got that far it would be madness not to reshell it, and put a new oil pump in it, and give it a full head job. You need a leakdown and compression test, and a look see down the bores with a good borescope.

[DJButler]

8.5 is the compression ratio (max and min volumes within cylinder/head) Pumping pressure should be around 160~180 psi dependant on quality of guage,wet or dry,hot or cold,cranking speed etc.

More important is the consistancy between cylinders, tiptop fresh engine should be within2% but 10% is workable on an older engine.

 

That's Helpful:)

[supra-ireland]

Ok, so I've done some more investigation and it's not looking good.

 

I took compression readings and got a depressing reading of around 50 on all cylinders.

 

A visual inspection shows no signs of excessive wear / leakage around the plugs / cam covers, etc.

 

The only thing that I saw to be damaged is the short rubber hose that comes out of the left cam cover, it looks very similar to the short hose that connects between the two cams.

 

So can I take it for sure that the head is gone or is there anything else that could be causing readings as low as 50?

[AndyT]

Piston rings shot.

[Whitesupraboy2]

Piston rings shot.

 

On all 6...what are the chances of that?!? must be low.

[keron]

make sure you have a very good battery when doing the compression test. a weak battery will give less reading...its odd to see 50 on all 6

[Chris Wilson]

As I said:

 

If you've got it seriously hot the rings will have lost their tension. Full engine strip, hone or rebore, and new pistons and rings. Having got that far it would be madness not to reshell it, and put a new oil pump in it, and give it a full head job. You need a leakdown and compression test, and a look see down the bores with a good borescope.

 

 

You have a classic case of severe overheating, if it's got hot enough to have de tensioned all the rings it's probably softened the heat treat in the head, and it's almost certainly scrap. It would be far cheapest to find a good used engine and swap it over.

[Chris Wilson]

make sure you have a very good battery when doing the compression test. a weak battery will give less reading...its odd to see 50 on all 6

 

Classic case, textbook I'd bet if he tows it at 40 MPH it'll start, assuming it's a manual. It won't run well, and I don't recommend it, but get enough revs on it, it may still fire up.

[supra-ireland]

Thanks for your diagnosis.

I guess I have to face facts.

I was just hoping that there might be another explanation but obviously not.

 

Can someone tell me what is the function of the damaged hose that I mentioned?

Also, what compression readings would a warped head give as opposed to damaged piston rings?

Someone else told me that a blocked exhaust could cause such compression readings to be found but that didn't make any sense to me.

 

I can't try to tow start it, as it's an Auto.

 

I might have to try a rebuild as the car's not in the UK

and I don't know anywhere that have any TT engines available.

[SimonB]

Can someone tell me what is the function of the damaged hose that I mentioned?

 

It's a breather, to remove excess crankcase pressure.

 

Also, what compression readings would a warped head give as opposed to damaged piston rings?

 

You need to get a leakdown test at the very least, you can't tell anything from a simple compression test.

[Soonto_HAS_soop]

Guessing that you were doing either 60 or 70mph, driving an engine for 8-10 minutes with no water in will fcuk it totally.

 

I go with what Mr Wilson is telling you on this one.

 

I had a water pipe go on me within 2 miles of home, had thrown the complete contents of the engine out, I was lucky to get home without it doing any major damage. This wasn't on the Supra mind you.