[Tim Corcoran]

I just used a hardened washer of the desired thickness from Ace Hardware

[Dragncar]

I cut my own from a piece of SS shim stock with tin snips. Used a piece of .062 with a .010 piece behind it.

[Formulas]

the last Pontiac pump i did i used a 80# pump with a smaller ball bearing got 70#

and it wasnt even the ball everyone flocks to it was the next size smaller than stock, a tweener

[grivera]

Originally Posted by Formulas

the last Pontiac pump i did i used a 80# pump with a smaller ball bearing got 70#

and it wasnt even the ball everyone flocks to it was the next size smaller than stock, a tweener

Did you use a washer?

[Formulas]

No washer,

I figured the smaller ball would knock off a few of the rated #80 pounds and i was fine with that, and give more bypass area and the longer spring would give more constant force ,

I think its a 19/32 ball which is in between the 9/16 and 5/8

I had to buy 15 or 20 of them if anybody wants one, they will work in my wrist rocket someday if i ever get tired of looking at them as iam not building to many more Pontiacs

[glhs#116]

My "upgrade" to an 80psi pump was the start of all my troubles. Cause of my first rebuild as the extra pump pressure started eating the distributor gear teeth and a shaving stuck the ball open giving me 0psi. That was my first rebuild.

I've run the 60psi pump ever since. Never had an issue with it. My engine may have had other things going on but all I'd say is to ask yourself if you really need the extra pressure or not.

Sam

[steve25]

What really helps in terms of loading and ware on the gears involved is a faster bypass rate and greater volume of that bypassed oil when cold.

[Steve C.]

Bronze Distributor Gear Durability

https://forums.maxperformanceinc.com...ht=Bronze+gear


.

[Old Goat Racer]

Quote:
Originally Posted by Old Goat Racer View Post
Would you have a part number or a link ?
Thanks, OGR

From PAULK
ARP 200-8643

Found them at Summit. Also a pack of 2. ARP 200-8642 for $1.81.
Thanks for your help.
OGR

[grivera]

Not advocating either 60 or 80 but certainly more than one way to do this in a performance engine - good read on the topic and JBP’s reasoning on an 80 psi pump: https://www.motortrend.com/how-to/hp...ervations/amp/

[Sirrotica]

I've always run the 60 PSI pump on small main journal engines, and the 80 PSI pump on the large main journal engines.

Pontiac engineers ran the 80 PSI pump on their endurance tests on the 73-74 SD engines, they found out that the extra 20 PSI was needed because of the necessity of overcoming centrifugal force on the large journal engines. Since I was running oval track engines these were exposed to many laps at high engine RPM, not the same as running down a drag strip at 10-13 seconds.

For long term, large main journal race engines I like the 80 PSI pump. My 428 ran 3 seasons without changing bearings in it. That's equal to hundreds of drag strip runs. The 400 engines I built for oval track use were just fine with 60 PSI pumps, and full groved mains.

When I was first learning about keeping Pontiac Stratostreak engines together when racing on oval tracks I learned the hard expensive lessons of what to do, as well as what not to do, when picking parts, and pieces for the bottom ends. I also learned how much a massive journal engine swells the crank when they heat up. When the crank gets hot it will grow a thousandth, or 2 taking away oil clearance, resulting in spun bearings. Keeping the oil cool, as well as leaving enough clearance to keep it flowing freely makes all the difference in the world. If you try to run factory clearances, you'll spin bearings every time. Opening up the bearing clearances requires a pump that can still keep the oil wedge under any, and all circumstances.

FWIW, I ran straight grade 40 weight Pennzoil racing oil in the oval track engines.

60 PSI pumps may work fine on a large journal street engine, or a mild drag strip engine, but run 25 laps on a hot night on a oval track, you'll find out that the 80 PSI pump works a whole lot better for longevity. I'll take replacing distributor gears periodically any day, over replacing an engine.