57 Lincoln 368 cu in engine


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By rvs57lin - 14 Years Ago
I am overhauling a 57 Lincoln 368 Cu In engine.  I  pretty much have it assembled and am now preoiling ths engine with a dummy dist that I have made up. I have a direct reading oil pressure gage and I get 20 PSI while tuning the oil pump drive counter-clockwise using a 1/2" electric drill.  I get oil drips off of the left bank rocker arms but very little oil is getting to the right bank as I do not get these oil drips like I do on the left bank.  I have removed the right bank rocker arm assy and blew air through the overflow hole in the shaft and got a steady air flow out of each of the rocker arm oil holes. ( I couldn't check the first and the last Rocker arm oil holes as I couldn't slide them away from the oil hole.)  The main oil hole in the shaft at the #3 cyl rocker arm stand is in fact lined up with the  oil hole in the in the head.  With the rocker shaft off the engine and I turn the oil pump drive I get oil pressure out of the oil hole in the head.  So  I think I have the oil paths all clear. The only thing I can think of is that I don't have enough oil pressure to get oil over to the right bank like it should be..  The external oil pump is located on the left side of the engine and therefor oil gets to the left bank first.  I know it doesn't take much oil to keep the rockers lubed but I would think I should get an equal amount on both banks.

Any thoughts on this would be greatly appreciated.

 Thanks  RV

By Ted - 14 Years Ago

Although simple logic says that the oil pump being on the left side of the engine supplies oil to the left rocker bank sounds good, that’s not the case.  For the conventional Y engines, the oil for the rockers for both banks is supplied from the center cam journal.  For the LYB engines (368’s included), the oil for the left bank comes from the #2 cam journal and for the right bank, the oil is supplied from the #4 cam journal.

 

If turning the oil pump with a drill motor, then your oil pressure should be considerably higher.  Assuming you’ve already checked all the bearing clearances and they are within specification, then I’d look hard at the oil pump next.  A complete disassembly of it and verifying its internal clearances would be easy enough.  The problem could be as simple as a stuck open bypass valve within the oil pump.  Here’s a past thread regarding the clearances and/or tolerances within the oil pump.

http://www.y-blocksforever.com/forums/Topic22717-3-1.aspx
By RB - 14 Years Ago
I doubt if the oil pressure issue is related to the rocker arm oiling. Try turning the engine 1/4 turn at a time for a couple rotations while re-trying to pressurizing the system and see if the right bank will get more oil.. Some Lincolns had 4 holes in the cam to provide oil to the top end rather than a continuous groove around the cam journal. If you are getting some oil to the right bank, more than likely there are no obstructions.. The oil pressure needs to be checked out. On a new engine even with loose bearing clearances, with cold oil you should see more than 50 lb of pressure. If you are using a heavier oil like straight 30w or 15/40 I always see 60 or 80 lb when pre-oiling. Double check and see that you did not forget to install an oil galley plug somewhere inside the engine. As Ted said remove the pump bypass spring and plunger make sure it is not sticking.. Even a worn pump should put out more pressure than you have. Another thing to check is the inlet pipe to the oil pump. Make sure you did not forget the rubber seal. also make sure it is tight. I have lost oil pressure and found that with thick oil that the pump can pull air at that joint, so it needs to be carefully assembled