Hi,
Often restricted venting is the cause of oil loss. The resultant
crankcase pressure forces oil from seals, the dipstick hole and other
locations. Worn rings on a high mileage or abused engine can cause blowby
which will also force oil out and can be felt as pulsating air when the oil
filler cap is removed. On late model MGBs the front tappet cover can become
strangely restricted which can cause oil loss of a quart in less than 100
miles, burned off the top of the pistons.
On a '74 B the oil loss you mention is almost negligible but if the
mileage is less than 90K check the carb vent hoses for crimping, the oil cap
for tightness and the valve cover elbow for restriction.
Have fun,
Jeff and your friends at Motorhead
2811-B Old Lee Hwy
Fairfax, VA 22031
(800) 527-3140
Home of daily drivers
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Subj: Advice needed: blowing oil
Date: 96-02-22 05:33:33 EST
From: Simon.MATTHEWS/OU=ag/OU=agrate1/OU=italy@sgpgtw.sgp.st.com
Sender: owner-mgs@triumph.cs.utah.edu
Reply-to: Simon.MATTHEWS/OU=ag/OU=agrate1/OU=italy@sgpgtw.sgp.st.com
To: mgs@autox.team.net
The engine on my '74 MGB appears to be pressurising the crankcase and
rocker -- some oil oil is being blown out -- however only a small
amount: my garage floor is certainly not covered with oil, and it
probably does not use more than a pint every 2000 miles.
There is no visible smoke when warm, the compression is OK (I don't
know the figures, but a garage tested it for me a while ago and stated
that it seemed OK).
What are the possible causes -- could this just be a blocked crankcase
breather -- in which case, does anyone know how it should be plumbed?
Car is US spec MGB, MY '74 with HIF carbs. Used to have air pump and
gulp valve (removed by PO).
In fact, could it be just the removal of the gulp valve that has
caused this (depending upon exactly what was done by PO when
removing)? Or is it a more serious problem just surfacing?
Regards,
Simon
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