Fuming

[morris-out]

Hi All

Looking for opinions on my engine problem, it‘s exhausting fumes from the crank case breather tube and from the oil filer when the cap is removed.
Assuming a good low compression engine has a compression of:
7.5 : 1 aprox. 130 PSI

My readings are:
Cylinder 1.- 140 PSI
Cylinder 2.- 150 PSI
Cylinder 3.- 135 PSI
Cylinder 4.- 145 PSI

The head was skimmed when my head gasket blew, so I assume that is why I’m getting higher reading s than expected although the difference between cylinder 2 and 3 is concerning.

My question is.- If compression figures are reasonably good for a low compression engine and the cylinder head was restored,( skim and valve guides), where would the crank case breather case fumes be coming from?
Are the piston rings worn sufficiently to cause this problem and is it time for an engine rebuild?
Looking forwards to your opinions
Thanks

Dennis

[bmcecosse]

Your readings are not too bad. The fumes only come from one place - the piston rings..... Answer is to either instigate a full rebore with new pistons - OR - suck the fumes away with a good connection to the inlet system. Poorest is the original connection from rocker cover to air filter casing... Is the rocker cover elbow blocked with gunge - or the tube blocked? This hardly does any sucking and plasters the paper air filter with oil.....not a great idea. Better is the later carb which has a direct connection on the RH side to take the hose - this sucks the fumes into the engine, and at least saves the filter from becoming blocked. Best of all is to make a hole in the inlet manifold - servo connection is ideal - then block it back to a 1/8" diameter (epoxy is good - then drill 1/8" hole in it) - and connect that to the rocker elbow. This upsets the idle slightly - but is VERY effective at sucking away fume escape. It's obviously not a 'fix' -= but it does allow a slightly worn engine to continue to function for a good few thousand miles more - which may be several years for your use of the car!

[morris-out]

thanks for your answer, I have the original system, rocker cover to air filter casing, did clean it all using air gun but no significant change, I think I will contemplate rebore and pistons, maybe fit a brand new 295 head that has sitting around for a few decades wrapped in a scum newspaper dated April 1980!!!!!
The idea of breathing those fumes which always seem for find their way in to the cab does not appeal to me, the engine would probably outlive me.
Thanks

Dennis

[bmcecosse]

Indeed - the fumes are carcinogenic - best to NOT breathe them! The 295 head will need skimming by ~ 80 thou.

[morris-out]

Thanks, now to make some decisions.