The Stovebolt Site Forums The Shop Area Engine Shop Oil leak

Hi,
Just recently got my truck on the road and after a run I've noticed an oil drip from the hole at the bottom of the flywheel cover. After the truck has been sitting for 10 minutes the leak stops but there is a bit of oil splashed about.

I'm suspecting the crankshaft rear oil seal and wondered if this could be the culprit - or does anyone know of anything else this could be?

The manual says you can change the bottom half of the seal in place but have to remove the engine to change the top half Hoping it may just be the bottom half but any info/advice would be great.

Thanks

Yep, most likely it is the rear main seal. The 216 CI six (and other early engines) is notorious for the drip, because of the early style "wick" seal. I was told by one gentleman who sold Chevrolets at a dealership back in the early 1950's that the Chevy dealership gave each buyer of cars and trucks a cardboard mat with a bow tie emblem on it to place under the vehicle when parked at home to protect the driveway/garage floor.
The book is correct, the lower half of the rear seal can be easily replaced by removing the main cap. The upper half is a bit of a problem and requires removal of the crankshaft to install a new upper half seal "by the book". Replacing only half of the seal usually does not fix the problem because the seal upper and lower halves wear at about the same rate. If it is leaking, the entire seal is compromised. There is however a product on the market known as a "sneaky pete" (google search this item) that can be purchased and used to replace the upper half without removal of the crankshaft. The degree of success is unknown, some swear by it, others do not. I have the same issue with my 51 truck engine but don't really get overlly concerned about an occassional drip, if they don't leak, they are out of oil!!

I replaced the seal in my 1951 216 several times. The last time I also replaced the main bearings and adjusted them to within minimum clearances. This solved the problem and the rear main doesn't leak. All this work was done with the engine in the truck.

Many thanks for the replys. I won't worry about the leak, but I will get the seals and replace them while looking at the bearings after I've had some fun over the Scottish summer.

Cheers
D

Fred, could you expand on your replacement of the main bearings please? Did all four upper mains slip right out and where did you get new main shims for them and where did you buy your mains from??

Denny Graham
Sandwich, IL

Denny,
I used the procedure in the manual so I dropped the crank some while repacing the mains. I bought my bearings on Ebay and they were NORS. I bought a set of shims from LMC that were Federal M. and they were useless. They were.006" thick! I tried to explain to LMC but all they said is they would ask their supplier. In the end I used some shims that I had and made some of my own.

When I went to start the motor after, it was fairly tight. I put some gas down the carb to avoid strain on the starter and then ran it for about 20 minutes. It is still a little tighter when warm but the rear main is sealed up pretty good.

Before I replaced them I tried putting strips of shim material on the insert of each main, one at a time to see how the clearance was. At .004" there was no drag at all! This was with no shims present as they had been removed a couple of years ago.

Fred

Thanks Fred
Denny Graham
Sandwich, IL