Guest Olivia 47 Posted December 5, 2006 Report Share Posted December 5, 2006 I purchased a new crank shaft and had my P15 rebuilt. It started nicely and ran well but would not hold oil pressure. My mechanic has determined that the bearings do fit the crank but are too small for the block. The block journels are stamped as bored 050 over. It is obvious that the bearings do not fit when you put one in the bottom journel and flush the bearing with the face and there is a 050 space between the bearing and the journel. The supplier of the crank and bearings says that this cannot be. The problem is that is what I have. I am looking for bearings with outside at 050 over. Do they exist or do I have to shim the outside of the bearings? Please Help, Greg Quote Link to comment Share on other sites More sharing options...
Young Ed Posted December 5, 2006 Report Share Posted December 5, 2006 Did you do the cam bearings? Thats the most common cause of oil pressure loss. The other bearings get issues after the cam ones go and the oil pressure drops. Quote Link to comment Share on other sites More sharing options...
Normspeed Posted December 5, 2006 Report Share Posted December 5, 2006 I would imagine that line boring a block would cause oversized journals, and if they are stamped that way, I'd believe it! Try calling Vintage Power Wagons, They know Mopar flatheads. They'll know the cure. They're also on the web. Quote Link to comment Share on other sites More sharing options...
james curl Posted December 5, 2006 Report Share Posted December 5, 2006 I had my block line bored, they machined material off of the mating surfaces making the opening elliptical, then rebored to standard diameter, givind a round opening. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted December 5, 2006 Report Share Posted December 5, 2006 If the crank if .050 under then the supplier of the crank has the responsibility to provide matching bearing shells. In fact I would find it very very unlikely that any machine shop would line bore the block to .050 never should there have been a core shift that needed cleaning up to this degree and as Mr. Curl stated..they machine at the boss first to allow it to be line bored and will go back to stock. It is my feeling that they just sent the wrong size bearings with the kit...the back of the shell will have the undersize stamped in the metal...check for this information first...maybe some one here can snap guage a torqued end cap for proper diameter.. Secondly the person assembling should have caught this with the first bearing cap being put on..the use of a plasti-gage is paramount for just this reason..with a song and dance like the one you are getting the music must be plenty loud. Quote Link to comment Share on other sites More sharing options...
bob westphal Posted December 5, 2006 Report Share Posted December 5, 2006 Tim is right. I can't believe anyone would assemble an engine if they saw any discrepancy with any bearings. If the main shells didn't fit the block why would he continue? A bearing insert should fit in the block with the tang in place and have the edges flush with the mating surface. There should be no gaps. If they did fit, checking clearances with plastigage is an absolute must!!!!!!!!!!! It sounds like you don't have a mechanic but someone who snookered you! Quote Link to comment Share on other sites More sharing options...
Normspeed Posted December 5, 2006 Report Share Posted December 5, 2006 Greg mentioned that the block journals are stamped as being .050 over, so I'd say the crank isn't the problem. I do agree, the rebuild shop should have caught this, but after dealing with my rebuild shop I'll believe anything. I still say call Vintage Power Wagons, they really know flathead sixes. Quote Link to comment Share on other sites More sharing options...
Guest Roadrunner Posted December 5, 2006 Report Share Posted December 5, 2006 Who assembled this engine? It actually ran like that? I have a 425 CADI with .103 crank endplay. It sounded like a powerhammer when running! That engine of yours must have sounded bad. I do agree that .050 line bore seems way drastic. Steve Quote Link to comment Share on other sites More sharing options...
james curl Posted December 6, 2006 Report Share Posted December 6, 2006 Now I know I am old, Tim called me Mr. Curl. I may be 70 but I still look at the world through 18 year old eyes and yes both my 55 chev pick up and my 48 Plymouth have modified engines. And I agree with Tim that any shop that would put a crank in a block without plastigaging the bearing clearance isn't much of a shop. I have seen junk yard people assemble an engine out of junk parts and even they plastigaged the rod and main bearing clearance. Quote Link to comment Share on other sites More sharing options...
grey beard Posted December 6, 2006 Report Share Posted December 6, 2006 Greg, You have been given some pretty good "party line" adviice here. It is the usual and customary way of doing business when building engines. Having said that, if all else fails and no one wants to accept responsibuilty for the problem, the true source of the pressure leakage can be verified by removing the pan and pressurizing the oil galleys with oil from a pre-lube arrangement, and watching to see where the oil is leaking from. This will tell you without a doubt if the pressure loss is cam or main bearings, etc., but it SURE is a messy job - I've done it on Cummins engkines - tasted oil for two days! LOL Quote Link to comment Share on other sites More sharing options...
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