[DeTomaso] Oil Pump Pressure

[Thomas Tornblom]

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
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