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If you look at their construction the rotary pumps have four lobes that pump a large slug of oil for each cycle with each slug causing a load on the drive train. The gear pump has multiples of the number of lobes, but they are all smaller and so the load that
each slug imposes is less. The total mass of oil pumped during a revolution will be approximately the same as a rotary and the total power needed to pump that volume may be close to the same, but the average stress load will be less due to the smaller slugs
being supplied.</div>
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<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Bill Lawrence</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
BN1 #554</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Healeys <healeys-bounces@autox.team.net> on behalf of Bob Spidell <bspidell@comcast.net><br>
<b>Sent:</b> Thursday, January 2, 2020 12:33 AM<br>
<b>To:</b> healeys@autox.team.net <healeys@autox.team.net><br>
<b>Subject:</b> Re: [Healeys] Oil Pumps</font>
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<div class="PlainText">I'm gonna make a SWAG that racers routinely run at 6K RPM or more. I
<br>
rarely go over 3,500 RPM in my BJ8, with 3.54 diff, and the 100s are <br>
known to break crankshafts if driven at 4K for long. Either the gear <br>
pumps run at reduced pressure at lower RPMs or the pulsed output of the <br>
vane-type is causing the problems.<br>
<br>
The DWM tech/sales people recommended the HC pump to me, and I asked <br>
about their suitability; hence my questions about the company. From <br>
their glossy catalog:<br>
<br>
"We recommend the high capacity for all road engines using a standard <br>
type crank up to 6000 rpm and the standard pump for race engines, steel <br>
cranks or anything over 6000 rpm."<br>
<br>
<br>
On 1/1/2020 3:43 PM, richard mayor wrote:<br>
> We racers have known about the dangers of using the rotor style pumps <br>
> for decades. I personally know more than half a dozen racers who <br>
> destroyed their camshafts using high volume oil pumps back in the 90s <br>
> - including me. I lost two camshafts! Jeff Johnk built a test bed, <br>
> did extensive testing of more than 50 hours on both style pumps, and <br>
> wrote an exhaustive article that appeared in the May, 1998, issue of <br>
> Chatter, entitled Pumped Up For Racing.<br>
> I suggest than anyone who is thinking about using a rotor style pump <br>
> read this article first.<br>
> Think about this for a minute. The rotor style pump caused problems in <br>
> the 2.6 liter 100/6 motors. Austin changed to a gear style pump a <br>
> month or so into the production of the 2.9 liter 3000 motors and the <br>
> problems went away. Why would anyone want to use a 100/6 oil pump?<br>
><br>
<br>
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