So I just had this motor built a 1969 430 technically its a 67 block i already had it running 40+ minutes on a start stand no oil leaks however when i got the torque converter and trans back on and when i lifted the motor to put it in the car oil started to leak from the seal should mention the motor is cranked downwards so im unsure if this is normal or not. So my question is it normal for there to be slight leakage when lifting a motor?
I would only consider that marginally acceptable if the motor was tilted way back and the rear main was completely submerged. There are no signs of a leak from the 40 minute run time.
I had an engine that leaked zero from the rear main when running, but oil poured out of it when I tilted it back pulling it out of the car. So there’s that.
Have given up on sealing the rear main on the Rivs 430. Its been in and out many times, several for just that reason. The factory spec'd the rope seal to seep for lubrication. If ya look at a un ground crank a machined pattern can be seen in the area the seal sits to wick oil into the seal. Using the newer rubber seals on a crank thats not machined smooth will still leak some oil. May even leak if it is machined. I'll just live with it.
Rear main seals can leak a bit when at the track and WOT. Normally, mine doesn't leak at all. The GN turbo engines can leak because of the boost. While at the NATS one year, I was looking at some Spool Fool Turbo parts and noticed a fiberglass inspection cover with a built in shelf over the weep hole. The idea was to fold up a piece of oil absorbent pad and insert it into the shelf. It was insanely expensive, like 160.00. I asked if they made one for the THM400. They said yes, but they didn't have any in BG. Anyway, it got me thinking I could make one myself. I bought an electrical box in Home Depot, and modified it. I then positioned it over the weep hole in my stock cover, and riveted it to the bottom. Cut a small piece of oil absorbent pad and put it inside. Every so often, I check it. If you have a significant leak, this could keep it off the bottom of your car and exhaust.
Was it coming out of the weep hole in the cover, or were you able to actually see it coming from the rear main? I have never heard of this or seen it myself.
I have to add that the ones that I really noted this happening were not new builds, and I had neglected to drain the oil before removing the engine.
Must have been rope seal motors that the seal was just barely hanging in there, and not leaking... yet.. Or it was the back of the oil pan... That should not happen, everything back there should be sealed up... airtight JW
