[DeTomaso] High Volume Oil Pump?

[Thomas Borcich]

Thanks Jack!!!

That's exactly the kind of information and experiences I was hoping for. I 
should have been more specific...at idle on a warm engine I get 40-50 pounds 
and up over 2500+ rpm I get 60+ pounds verified on a mechanical and the OEM 
stock dash gauge. The stock gauge reads exactly as the mechanical gauge 
(surprise)...I am doing exactly as you suggest and am running a mechanical 
gauge on a T-fitting off the block where the stock (new/replaced) sending 
unit is.

My thought was that a high volume pump would make the motor live 
longer...but I'm not running remote filters or coolers so I will stick with 
a stock pump...but will change to a better pump drive shaft and change to 
the double roll pin for added insurance. Totally makes sense. Thanks

Best regards,

Tom Borcich



----- Original Message ----- 
From: <JDeRyke at aol.com>
To: <Tborcich at msn.com>; <detomaso at realbig.com>
Sent: Wednesday, May 16, 2007 9:47 AM
Subject: Re: [DeTomaso] High Volume Oil Pump?


> Tom, most guys find that a stock pump works just fine unless you are 
> running
> a remote oil filter AND a remote oil cooler; then, due to flow 
> restrictions
> from long oil lines, sometimes a high volume unit is needed to maintain
> pressure.  FWIW, I run both and still use a stock pump. True pressure at 
> start-up
> (cold engine) will be 75-90 psi, hot pressure @2500 should exceed 50 psi, 
> idle
> should be 20-30 psi. More than 90 psi can cause problems with oil filters 
> and oil
> coolers as they will sometimes rupture w/cold oil, so I recommend NOT 
> using a
> heavy spring in the oil pump relief valve- which is often the only 
> difference
> between a stock and a 'high-pressure' pump. I once blew a Wix filter clear
> off the block at 6500 rpms w/a 'high pressure' pump, heavy spring & 50-wt 
> race
> oil....
> You should verify the pressure readout- as with the stock water temp 
> gauge, a
> stock oil pressure gauge lies constantly. Add a tee fitting to the block
> outlet, screw the stock sender into the side port and a cheap mechanical 
> gauge
> from Pep Boyz to the top. By comparing both gauges, this will give you a 
> check of
> the notoriously inaccurate stock electric gauge. FWIW, I once talked one
> vendor into letting me 'borrow' a handful of senders for our '72: of nine 
> (9)
> brand new senders, ALL gave different values on the same engine and all 
> were lower
> than my $15 mechanical gauge! I picked the highest-reading of the bunch 
> but
> left the mechanical gauge on the engine.... since 1990, with zero 
> problems.
> IMHO, a stock gauge is best regarded as an 'idiot-light' to tell you the 
> pump is
> turning but no other accurate info can be gotten.
> Second good idea: add an aftermarket pump driveshaft to the oil pump you
> choose. Stockers are apparently made of old coat-hangers and will twist, 
> then
> break. A Moroso, Milodon or SVO unit of 4130-steel sells for $17 and will 
> not
> break or twist. Finally, an integral part of the oil pump drive is a 
> double
> thickness roll pin (or a piece of drill rod) in the distributor drive 
> gear. Good
> luck- J DeRyke<BR><BR><BR>**************************************<BR> See 
> what's
> free at http://www.aol.com.</HTML>
>