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View Full Version : Big oil leak


bmacpiper
07-25-2010, 07:14 AM
Hello all,
Hope you've been well. I've been enjoying our annual two weeks of sun here in Seattle, so I've been out and about.

Pulled the '70 S out of the garage yesterday, and went through a few things.
Compression: 180, 172, 188, 178 (from left to right as you look into the engine--which end is #1?)
Set plugs to .025.
Dwell was around 55 degrees
Couldn't find timing marks, but engine runs well enough for now
Idle set to 1200 or so

The mini has mostly sat in my garage, and has always lost a bit of oil on the floor. It started smoking as it heated up, and I could see oil burning off the exhaust, pretty much where the exhaust headers go 2-into-1 and curve back. As the engine warmed up more, I started having a pretty steady drip, that originates somewhere above the left side spicer/universal joint, and drips off of the same. Within about 10 minutes I had a circle of oil about 6" in diameter on the driveway. I took a quick spin around the block, and left a trail of drips every 12" into the driveway when I got back. I also noticed heavy knocking in the valves if I give any sort of serious throttle, but it is much louder than I'd expect, almost like something loose and banging around, more on the right side than the left. I also feel like the engine runs really hot--one symptom is that the oil fill cap is hard to remove after the engine warms up, and there is steam/smoke inside the valve cover when you open the cap. I am still a total neophyte with minis, but it just "feels" too hot.

Something is clearly amiss. Picture below (mini on ramps).

Any common/obvious leaks in this region? Is my next stop an engine rebuild? How is the compression as listed above, i.e. normal or way low?

In any case, glad to have her running again, even if just for diagnosing a period of non-running...it is movement...

talk soon,
Ben McC

http://i258.photobucket.com/albums/hh280/bmacpiper/1970%20Cooper%20S/IMG_0255.jpg

mascher
07-27-2010, 06:47 AM
For the oil leak, start at the top. Try a new valve cover gasket, all of the oil you see could originate there. Next check the torque on the side cover bolts.

It's hard to diagnose a knocking sound without hearing it. It is possible that old gas combined with too much ignition advance is causing the engine into preignition which is very bad. It's hard to say since it could also be the inner U/J hitting the exhaust.

Kelley

bmacpiper
07-27-2010, 10:19 AM
Thanks Kelley, will have a closer look.
bmc