[DeTomaso] Oil Pump Pressure

[shawkins777 at comcast.net]

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 
_______________________________________________ 

Detomaso Forum Managed by POCA 

DeTomaso mailing list 
DeTomaso at poca.com 
http://poca.com/mailman/listinfo/detomaso