280ce Oil Breather Problem

[greedygormster]

Hi - I hope someone can help me. My 1978 280ce is currently blowing oil through a breather pipe into the air filter and thence into the injectors. Making it run like a bag of old spanners, and sometimes not at all.

Can't work out why she's doing this to me, after all the cash I've lavished on her recently. I'd really appreciate some advice!

Thanks!

 

[television]

Hi - I hope someone can help me. My 1978 280ce is currently blowing oil through a breather pipe into the air filter and thence into the injectors. Making it run like a bag of old spanners, and sometimes not at all.

Can't work out why she's doing this to me, after all the cash I've lavished on her recently. I'd really appreciate some advice!

Thanks!

Hello and welcome, sadly it would appear that you have a broken piston ring that causes crankcase compression.

Malcolm

 

[chelsw6]

Have you checked that its not over filled with oil.

 

[Hibbo]

Blow-by!

 

[greedygormster]

Hi - thanks for the replies. It isn't overfilled with oil. I did a compression test on it this afternoon - took all the plugs out and no.1 cylinder's plug was covered in oil. Cylinders 2-6 were showing 8.2 psi, but no.1 (with the oil) was showing 10.2 . Shouldn't this be lower for a broken piston ring, or is this something to do with it being a closed crankcase system?

Confused!

 

[television]

Hi - thanks for the replies. It isn't overfilled with oil. I did a compression test on it this afternoon - took all the plugs out and no.1 cylinder's plug was covered in oil. Cylinders 2-6 were showing 8.2 psi, but no.1 (with the oil) was showing 10.2 . Shouldn't this be lower for a broken piston ring, or is this something to do with it being a closed crankcase system?

Confused!

The normal way to test for compression is to do a test and if low.then you inject the oil into the cylinder to see if it comes up.

The fact the there is oil in the bore could mask the fault as normally when you put the oil in the compression returning to normal.

Only by washing down the bore first can you be sure. As the plug is oiled up, the valves could do this, but this would not cause crankcase compression.

The engine does not have to come out to replace the rings on that cylinder but the head and the sump must come off.

Malcolm

 

[Ultymate]

You've quoted figures of 8.2 PSI and 10.2 PSI I hope you mean bars and not PSI or you have got a seriously crackered engine the high reading in the cylinder with the oil present will be caused by excessive carbon formation due to the burning of the oil, the carbon will reduce the space of the combustion chamber and bump up your compression reading. Your engine must have been smoking for a long time to produce this effect and you must have been topping up the oil on a regular basis

 

[greedygormster]

Yes - bar and not psi. I think it's the oil present in the cylinder giving the iffy reading, because there isn't much carbon on the plug. Hasn't smoked much and I haven't needed to top-up, but I haven't run it much either. I'm going to investigate the exhaust valve clearances at the weekend - apparently if there's too much clearance oil will get in on the inlet stroke and then blow through - it's worth looking at I think, and I'll post the results!

Thanks

 

[television]

Any oil from the valves would get burnt, and has nothing to do with crankcase compression.

malcolm

 

[Ultymate]

You say you've lavished a lot of cash on the car recently, what work have you had done ?