Originally Posted by Stardust
I bought my 42 Carver last year. It saw a new short block (454 Gas Mercruiser)on the starboard side just before my purchase. The port oil pressure runs at 40psi. The star. shows ~80 cold and ~65-70 at oper. temp.
I am seeing a fair amount of leakage in the bilge. Could this be the high pressure forcing oil past the rear seal (assuming the oil gage is accurate)?
Is there a way to adjust the pressure?
There is a gap and lip between the bearing and rear seal. You can not blow oil out this seal from high oil pressure.
When I rebuilt LBCs, I used Melling 77 HV oil pumps. Most rebuild shops do. The pressure may be higher on a fresh block (closer tolerances) and your readings could be correct. Yep, Up there high.
Put an old fashioned mechanical gage on both of the motors, You may see something totally different than what the electric gages say. Full page of reasons for this.
On the oil leak;
I have found truck & auto blocks used as replacement engines. Done rite (rarely) it's O K. Look for were oil dip stick tubes are located. Some LBCs go into the pan, some into the block. When there is a mis match, a lot of perm-a-tex is used and usually fails.
Marine blocks use brass freeze plug, including the cap at the end of the cam shaft. I have seen the steel cap (plug) rusted and leaking oil from the back cam bearing (not open or lipped). Also, the distributor gasket can make a heck of a mess. Depending on where your H/E is, You may not even see this.
Good luck, tell us what you find.