Bill, A high volume oil pump has the same relief spring and does not
make any more pressure than a standard pump, it just has the capability
to a higher volume of oil. That is why it doesn't drop much at idle. If
the rebuild was done correctly there is no need for one. Most
applications for high-volume pumps are for either racing or worn-out
engines, both cases because of the looser bearing clearances.
Your crank seals are not under direct oil pressure, only the air
pressure inside the oil pan. Since you are going to the trouble of
pulling the transmission, flywheel and pan, you might as well buy the
best seal. I have had good luck with the Fel-Pro Teflon seals, the part
number for the SBF is Z2941, they're about $40 vs. the $15 for a regular
one but will stay flexible longer and seal better. Just my two cents.
Bugz
-----Original Message-----
From: Bill Waite
Sent: Tuesday, June 29, 2010 1:31 PM
To: tigers@autox.team.net
Subject: [Tigers] Oil Pressure & Rear Main Leak Question
For a number of years (ever since day one with a newly rebuilt 302
roller cam motor), I've lived with a rear main oil leak. Not bad enough
to demand fixing... but bothersome. I've finally decided to fix it.
It's an '86 "RHO" (an early Ford crate engine... remanufactured 302 HO).
It has the one piece rear main seal, so I'll have to pull the trans to
get at it.
However, one concern I have is with the oil pressure. When I got the
engine, I installed a Melling M-68HV high volume oil pump. The pressure
has always been on the "high" side (at least I think it is high). At
idle or higher RPM's, it stays at a more or less constant 60 to 65 lbs.
Is it possible that the leak is possibly a result of running more
pressure than I really need? The PCV and breather are fine, so I don't
think it is a crankcase pressure issue.
Guess what I need advice on is whether I should change the oil pump to a
standard volume street type to run at a somewhat lower pressure? If
so... any recommendations on the oil pump brand & model number?
Also: any suggestions regarding a specific type or brand of rear main
seal?
Thanks in advance.
Bill Waite
Grand Rapids, MI
B382100437
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