compression results - blown HG or excess crankcase pressure?
Posted: Sat Aug 01, 2009 4:27 pm
HI
Sorry for long post. My friends car recently broke down and i was wondering if anyone could help with working out whats wrong. 1.05l 4 speed fox coupe
He was driving up a hill trying to over take in third gear at fairly high revs. After about 30-40s of this he felt the car was down on power and he eased off. At the next roundabout a few hundred yards down the engine definately felt down on power and the oil light flashed once (and possibly temp) but went out again. He carried on driving (!) for another 5 mins until smoke started billowing out the back and drivers side of bonnet.
Once he finally stopped he also noticed the following:
Temp guage read about 3/4 of the way up
Heater vents were blowing hot air in despite being on cold
The back of the engine bay is covered in oil (presumably from a hole in the breather)
The RAC guy found no oil in it and recconed that it had excess crankcase pressure, following having not enough oil leading to engine wear, with possibly blocked breather system.
I assumed it was f###ed but checked the compression out of curiosity and found compression after 2-3 strokes were: cylinder 1 (13 bar) - 2 (1 bar), 3 (1 bar), 4 (13 bar).
Normal spec is 10-15 bar, lowest accpetable level is 7 according to haynes.
My question is, does this look like the figures you'd expect from a worn engine with excess crankcase pressure, or could it simply be a head gasket failure between cylinders 2 and 3 and an oil port, thereby pressurizing the oil. Surely if it was oil starved the other cylinders would be down too and the warning light would have stayed on?
So what do you reckon high crankcase pressure caused by no oil, or blown HG into an oil port therefore dumping all the oil out the breather? Im going to remove the head and see but just wondering what you guys thought.
There is no mayonaise under the oil cap, btw.
Sorry for long post. My friends car recently broke down and i was wondering if anyone could help with working out whats wrong. 1.05l 4 speed fox coupe
He was driving up a hill trying to over take in third gear at fairly high revs. After about 30-40s of this he felt the car was down on power and he eased off. At the next roundabout a few hundred yards down the engine definately felt down on power and the oil light flashed once (and possibly temp) but went out again. He carried on driving (!) for another 5 mins until smoke started billowing out the back and drivers side of bonnet.
Once he finally stopped he also noticed the following:
Temp guage read about 3/4 of the way up
Heater vents were blowing hot air in despite being on cold
The back of the engine bay is covered in oil (presumably from a hole in the breather)
The RAC guy found no oil in it and recconed that it had excess crankcase pressure, following having not enough oil leading to engine wear, with possibly blocked breather system.
I assumed it was f###ed but checked the compression out of curiosity and found compression after 2-3 strokes were: cylinder 1 (13 bar) - 2 (1 bar), 3 (1 bar), 4 (13 bar).
Normal spec is 10-15 bar, lowest accpetable level is 7 according to haynes.
My question is, does this look like the figures you'd expect from a worn engine with excess crankcase pressure, or could it simply be a head gasket failure between cylinders 2 and 3 and an oil port, thereby pressurizing the oil. Surely if it was oil starved the other cylinders would be down too and the warning light would have stayed on?
So what do you reckon high crankcase pressure caused by no oil, or blown HG into an oil port therefore dumping all the oil out the breather? Im going to remove the head and see but just wondering what you guys thought.
There is no mayonaise under the oil cap, btw.