Compression Nightmare.

[Bjork]

Hi guys,

Ok, K-Jet 1800 16v engine (1991). Can't drive the car as engine is too bad. Engine turns over and exhaust smokes alot. Whiteish smoke but smells of oil.

Done a compression test as follows. (Done on warm engine):

Cylinder 1 = Dry test 4 bar/ 55psi
                 Wet test 7 bar/100psi

Cylinder 2 = Dry test 4 bar/ 55psi
                 Wet test 6 bar/ 85psi

Cylinder 3 = Dry test 0
                 Wet test = 0

Cylinder 4 = Dry test 0
                 Wet test = 0

Whilst doing the compression test there was a whitish mist comping out of cylinders 3 and 4.

Coolant is fine, as is the oil. (No oil in coolant and no mayo in oil).

Now I always thought if there was no compression between 2 cylinders it suggested head gasket, but there are no other symptoms of this. 

Been thinking along lines of valves or lifters but could also be pistons or rings.

Could it be any of these or are do you think the above points to one thing more than any of the others?

Any help/advice would be greatly appreciated.



p.s. I've got a replacement cylinder head to go on the car but maybe this wouldn't be as beneficial as an engine transplant if it came down to Pistons. Or do you think I could tackle the Piston problem with the engine in the car and approaching them by going through the sump?

Cheers in avance.

[JimR]

To be honest your best bet is to whip the head off and look, you should be able to see at a glance if its any one of those problem (apart from the rings of course)

[Bjork]

Is fitting new rings a big job or do ya think that once the head is off then the hard part's out of the way?

[tobz.]

The zero compression on 3 & 4 would definately suggest that the gasket has burnt out between the two cylinders. This wouldn't affect the coolant or oil as there are no channels between the cylinders.
The compression is also horribly low on 1 & 2, as a comparison I was getting 115psi on all cylinders of my aircooled t25 which has a much lower compression ratio than the 16v kr.

The pistons and rings can be changed with the engine in the car by simply removing the sump and undoing the big-end shells. However it sounds like things are very worn so the bores are likely to need re-honing at least which is an engine out job.

[DarnPB]

The zero compression on 3 & 4 would definately suggest that the gasket has burnt out between the two cylinders. This wouldn't affect the coolant or oil as there are no channels between the cylinders.
The compression is also horribly low on 1 & 2, as a comparison I was getting 115psi on all cylinders of my aircooled t25 which has a much lower compression ratio than the 16v kr.

The pistons and rings can be changed with the engine in the car by simply removing the sump and undoing the big-end shells. However it sounds like things are very worn so the bores are likely to need re-honing at least which is an engine out job.

The first part of this I agree with 100%. The head needs to come off.

The second part I agree with, but you may just need a change of rings and a glaze bust, unless the rings are broken. This can be done, as already said, with the engine in situ. This is also a good time to replace the big end shells and generally give all exposed components a damn good service. ie, clean out the ring grooves, clean the pistons of carbon and coke, service the head and re-lap the valves in etc. Also a good idea to replace the oil pump if you are keeping the car for a while.

I did this on my old 8v and it restored all the power it once had. Well worth doing.

[Bjork]

Cheers guys. What is a glaze bust as you mentioned?

Was thinkning if it did come down to a full engine out job might be tempted to try and source a decent transplant engine.



As for now the car's going nowhere so head off and a bit of investigation. I'm sure I'll be back for advice when i get stuck. 

[DOA]

Transplant seems the easiest and probably cheapest option really although you can never know the condition of a second hand engine without stripping it I spose.
 Head on its own isnt too bad a job but getting the pistons out when the engine is in the car is just daft IMO, too many chances to drop stuff in the engine and not notice, too much time spent bent over the engine bay (I have a bad back lol) etc etc and it really isnt that bad a job to get an engine out once you have started.
Personally Id be thinking, Hmm, fate seems to be telling me to stick an ABF in that hole there.

[Conker]

This is very unlikely but I thought its worth a post...

Double check your injectors are seated properly with a good seal in cylinders 1 and 2. You never know, it could be a massive air leak through the injector port.


Doubt it though chap, but its a free test!
 

[Bjork]

Cheers Conker, I'll look at them.

DOA, think it might be the option I go for. Gonna take off head anyway and see if it's something obvious first because if I do decide to transplant I'm gonna have to shell out for an engine hoist. 

[danny_p]

Done a compression test as follows. (Done on warm engine):

Cylinder 1 = Dry test 4 bar/ 55psi
                 Wet test 7 bar/100psi

Cylinder 2 = Dry test 4 bar/ 55psi
                 Wet test 6 bar/ 85psi

Cylinder 3 = Dry test 0
                 Wet test = 0

Cylinder 4 = Dry test 0
                 Wet test = 0

it's buggerd  end off   you should be hitting 13 bar.    by the look of those reslults it's a suprise it runs

with compression ratios that low and white oil smoke out the exhaust the engine is DEAD  don't even bother lifting the head  just take the whole motor out and throw it away.