The Stovebolt Site Forums The Shop Area Engine Shop 235 Leaking oil from rear main

I had my 54 235 engine completly overhauled by a machine shop. When I first got it home I noticed it had a oil leak, I placed some heavy cardboard under it to soak up the oil. I have now put 269 miles on it and have added 2 1/2 qts. of oil to make it to the full mark. Did they forget the rear main oil seal? I drove it about 40 miles to a car show yesterday, checked the oil, was at the add mark. I noticed when I backed it up to the curb at the show there were oil drips about every foot plus a big spot on the street when we left. I haven't talked to the shop about it yet. Any advice??

I would take it back and show them. You can't live with a leak that large.

Here's something that happened to me after I had my engine rebuilt by and experienced builder: our engines have alignment pins on the crank shaft to correctly align the flywheel on the crank. The holes those pins go into go all the way through the crank flange into the inside of the engine. I had two pins missing and I was losing oil on the garage floor bad. I was convinced it was the rear main. I changed the rear main out with the engine in the truck. It did no good until an older gentleman mechanic told me what it was. I dropped the pan, again, got some pins, pounded them in and that was it.
Check for those pins.

Did he use a neoprene seal? 1954 235s still used shims on the mains. Some people try to use the later neoprene seal on these engines with limited success as the shims hold the ends of the seals apart, this creates a path for the oil. The seal groove in the block and cap is also deeper so the seal is not held tight to the crank. I would always use a rope seal on these engines.

As I mentioned in the above post, I also pulled a seal out of the engine that the rebuilder had put in. It was a neopreme seal and I replaced it with a rope seal. I agree with Pre '68 Dave, the rope seals do a better job in these engines, but I knew after I replaced the seal, I had other problems because the oil never slowed down with a new seal until I discovered the missing pins.

A missing flywheel bolt will do the same thing, as I discovered shortly after buying my 59 3800 dually. It cost me a clutch in pretty short order, and while changing it, I discovered the missing bolt. The PO had cross-threaded the bolt during reassembly after an out-of-frame rebuild, and just discarded that one. I was able to re-tap the hole in the crank flange and replace the bolt, stopping the oil leak.
Jerry

Good point, Jerry. Just like the alignment pin, an open hole is a direct hole to all the oil in the pan. And, yes, it will necessitate a new clutch and allot of oil to clean up.

Update on leak, they pulled the engine and found the seal was bad. Replaced & sofar OK. Also found a pin hole in the pan.

I am glad they fixed it for you. As a comment, seals don't come bad out of the package, at least I haven't heard of it.

Thanks for the tips guys,

I found a good deal today on refreshed 235 today. The guy I bought it from says it has about 5,000 miles on it. It looks clean. It has an new fuel pump, Carb, and water pump. He also gave me a couple of lightly used clutches. Said its a 235 out of a 54. Full Pressure engine. I will post some pictures tomorrow. If anyone can give me some tips on what will need to be changed to make it fit, I would greatly appreciate it.

DG