QuestionQUESTION: I'm rebuilding a 1939 Chevrolet 216 CID engine. I have two rear main bearing choices; one bearing has a curved groove cut into the bearing I.D. surface and it also a hole drilled through the lower shell that would connect with the lower main cap oil drain. The second bearing choice has no groove and no hole to connect with the lower main cap oil drain, yet both bearings are for a 1939 216, which do I use? Secondly, the rear main rope seal (that I received in the rebuild kit) just slides into the rear cap and rear block register with no interference, there is no press-fit. I believe the rope seal is supposed to be tight and needs to be pressed into both locations, can you please advise.
Thank you.
ANSWER: I need you to check something. There should not be a hole in the rear main bearing cap in the bearing seat. The hole should be between the bearing seat and the main seal. let me know and we will go from there.
Brad
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QUESTION: The hole originates at the bearing seat and then continues downward till it connects with a hole that protrudes into the rear main seal area. This perpendicular connecting hole also goes through to the crankcase. This hole is regulated with a small ball that is trapped between the rear main seal area and a pin.
ANSWER: You are sending me back into my way back time machine reference library on this one so here goes. First according to my reference material the upper half of the main bearing shell is held in place by a dowel in the block. Second on the 1939 engine there was no rear main seal, just the oil slinger flange on the shaft riding in a groove behind the rear main bearing. So, the question to you is, do you have the shaft out of the engine and is the upper shell retained by a dowel in the block? let me know.
Brad
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Bearings
QUESTION: Yes, the crankshaft is out of the engine. The upper and lower bearing shells each have a dowel pin built into the backside of each respective bearing. The engine block and the lower main cap both have holes to accept the bearing dowel pins. There are no dowel pins in the block or lower cap. So, I need to confirm two items: 1) Are you saying that there is nothing to install as a seal in the back of the block, the slinger does all the work? Is there any trick or aftermarket item that can be installed with the slinger to provide a better seal when the engine is off? 2) I still don't know which rear bearing to use, the bearing with the spiral grooves that feed oil to the removal channels or the bearing with no spiral grooves and no holes for the oil removal holes. Each bearing does have all the proper oil supply holes, the difference has to do with the spiral groove. Please see the attached picture. Thank you.
AnswerAs far as which bearing to use i think that going back to the seller is a smart bet right now. Those old Chevy engine only developed 15 pounds of oil pressure on a good day and the slinger worked well as long as the bearing clearance was within specifications. There is no aftermarket add on for that rear seal that I know of.
Brad
