Vacuum pump help

[HR9121]

I've been told that when installing at vacuum pump on a motor with a 2 piece rear seal that you have to turn it around backwards. Not sure if this is the case or not but hoping someone up here would know for sure. Thanks for any help or suggestions.

[Bill Baer]

Cooter
I run both of crankshaft seals and the cam seal (Jessel belt drive) in the normally installed configuration.
But I don't know how much vacuumn I am making or how much air inlet leakage their is either.
I do know that on the Dyno it was good for a disappointing 13 HP my Engine builder has seen as much as 40 HP gain but in those cases they used a different piston ring combination and turned the vacuumn pump faster. In my case it's keeps the alcohol from milking up the oil which was what I had in mind anyway.

[HR9121]

Thanks for the info Bill. My problem is for some reason from time to time when I stage and go to the mat it wants to squirt a little oil past the seal. Doesn't happen everytime but gets worse in later rounds when everything gets heated up I guess.

[Rick Bailey]

Good guestion, and I've heard that about the seal myself. I'm going to get my first experiance with a pump myself.

But i'll take a stab it on your deal of it leaking. considering the seal is in backwards the motor, just before WOT has some positive crankcase pressure therfore blowing out a little oil..... then when you deck the motor it begins to built vacum and no longer leaks....

I supposed this could be the case no matter which way the seal was.....

let us know....

[Chuck Westcott]

Felpro makes the double lipped seal for that purpose. When we dynoed my Motor we played with the vac pop off and finalized it at 14 in. Why ? Because that is when the Oil Pressure began to spike. Also the HP peaked at 18 to 20 in, but in my style racing I'd rather have consistancy with Vac and Oil Pressure. So don't just throw a Vac Pump on there and expect huge gaines with out determing where you need to pop it off and what ring package you have. That could provide issues with wrist Pins as well as Bearings and leaks. If I were running Comp with 0/5 oil and a very low tension ring package that would be a different story. I'm not an Engine Builder, but the Guy's that do mine are among the best in the business.

[pmrphil]

The Fel-Pro seal is the viton one, it's quite a bit stiffer than the normal silicone seal and should be installed in the normal fashion - I think the number is 2902, but double check to make sure.