[DeTomaso] Oil Pump Pressure

[Julian Kift]

Yes, oil pumps have an internal relief spring, the high pressure pump just uses a higher resistance spring. The actual pressure your gauge reads is will be is a function of tolerances in your engine, oil viscosity and location of the pressure sender.
 
Julian
 

> Date: Thu, 31 Jan 2013 08:33:13 +0100
> From: thomas at hax.se
> To: detomaso at poca.com
> Subject: Re: [DeTomaso] Oil Pump Pressure
> 
> The "hi volume" refers to the amount of oil through the oil pump, not 
> through the engine.
> 
> If only the oil pump is changed, it will mean that more oil passes 
> directly back into the oil pan through the bypass, and as a hi volume 
> pump takes more power from the distributor gear, it means more wear and 
> more heat.
> 
> Thomas
> 
> 2013-01-31 07:16, shawkins777 at comcast.net skrev:
> > I think the term Hi-volume is misleading, if nothing else is changed in an engine but the oil pump, you can't increase volume without increasing pressure.
> >
> > Steve
> >
> > ----- Original Message -----
> > From: "michael at michaelshortt.com"<michaelsavga at gmail.com>
> > To: detomaso at poca.com
> > Sent: Wednesday, January 30, 2013 10:07:46 PM
> > Subject: [DeTomaso] Oil Pump Pressure
> >
> > Worth sharing I thought.
> >
> > Michael Shortt
> > ---------- Forwarded message ----------
> > From: "Ronak, T.P. (Timothy)
> >
> >> Karl,
> >> The term Hi-Output pump is not descriptive enough ... it is either
> > Hi-Volume
> >> standard pressure or Hi-Volume High Pressure. All you need for a stock
> > engine
> >> is 10 Pounds of pressure for each 1000 RPM of engine speed. Any pressure
> >> beyond that and you are introducing parasitic HP losses by forcing the
> > engine
> >> to work harder to spin the pump. The max pressure you need in a stock
> > 6000 RPM
> >> engine is 60 pounds when revving at 6000. I personally feel best with a
> >> minimum pressure at idle of 25-28 lbs. Unless you are starting the car at
> > -40
> >> or you have a mechanical interference inside the pump it is not likely you
> >> will twist off the oil pump drive or excessively wear the Cam distributer
> >> drive due to the additional loads generated by the High VOLUME pump.
> >>
> >> I am assuming you were sold a Hi-Volume standard pressure pump and the
> >> pressure bypass spring in the pump itself will ensure you do not create an
> >> excessive oil pressure in the system. I would leave the pump alone and
> > simply
> >> observe the oil pressure at startup. Ideally you want to run 10/30 or
> >> equivalent synthetic oil and after breakin simply note the oil pressure
> > once
> >> warm and know that you may be able to mitigate some of the pressure by
> > running
> >> a thinner or lower viscosity oil like 10/20. I would not advocate a '0'
> > weight
> >> oil as the tolerances we run on the older V8 engines are too large and
> > require
> >> some oil wedge to develop to prevent bearing contact. It does depend on
> > the
> >> climate you intend to operate the car and weather there will be lots of
> > COLD
> >> sub zero starts.
> >>
> >> Sounded like you were looking for a recommendation ... so here it is ...
> > If
> >> you are running a Hi-Volume pump leave it in and you will be fine just
> > look to
> >> observe that Oil pressure does not exceed 60 PSI when revving above 4500
> > RPM
> >> and that you have at least 25 pounds at idle ... If you KNOW for a fact
> > you
> >> are running a HI-PRESSURE pump (Not a HIGH VOLUME pump) you might want to
> >> reconsider your choice. I can not imagine that you used a hi-pressure
> > pump as
> >> they are very difficult to obtain and are not easily purchasable from a
> > NON
> >> performance company as they are rarely stocked or sold so most likely the
> > term
> >> hi-output refers to Volume and NOT pressure. If you have your receipt for
> > the
> >> pump we could look up the part number and stop speculating and determine
> > which
> >> pump you have.
> >>
> >> Lunati actually recommended that I NOT EXCEED 60 PSI on my stroker motor
> > as
> >> they said it would create too much windage at RPM inside the crankcase
> > and it
> >> would make the oil rings work too hard to prevent oil in the combustion
> >> chamber and felt that the 58psi regulated Hi-Volume pump they sold me was
> > the
> >> best alternative next to a dry sump.
> >>
> >> If you have any questions feel free to call me.
> >> Best Regards,
> >> Tim Ronak
> >> Senior Services Consultant
> >> AkzoNobel Automotive and Aerospace Coatings NA
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> 
> 
> -- 
> Real life: Thomas Törnblom Email: thomas at hax.se
> Snail mail: Banvallsvägen 14 Phone: +46 18 32 31 18
> S - 754 40 Uppsala, Sweden Mobile: +46 76 209 8320
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