Shelby Oil Pump Modification

rr64_old · February 3, 2010 at 4:58 PM

Shelby American modified stock 260/289 oil pumps for racing by adding a 0.200 inch thick shim behind the internal relief valve springs. This was done for race Cobras and later racing GT350s.

My question is, have any forum members done this themselves and determined what affect (how much did hot oil pressure increase) the shim had on the relief pressure of the valve?

Dan

[Blocked Image: http://i144.photobucket.com/albums/r187/rr64/IMG_1559-Copy.jpg]

Edited by - rr64 on 02/03/2010 17:37:55

Edited by - rr64 on 02/03/2010 18:42:25

Edited by - rr64 on 02/03/2010 18:43:04

jwc66k · February 3, 2010 at 6:36 PM

It's supposed to give you higher oil pressure by raising the relief threshold. We did a similar trick on Formula V engines and on Baja 1000 engines. The only drawback is when the oil is cold you may blow the seams on your oil filter.

Jim

C6ZZKGT · February 3, 2010 at 7:28 PM Official Post

Dan, Is that bracing on the oil pump pickup part of a race Cobra modification as well? A friend of mine has a pickup like that and we are both unsure as to what it is for.

-Fred-

RalphJr · February 3, 2010 at 7:52 PM

jwc66k,

Who's Baja 1000 engines?

I supported the Dodge and Ford race teams in the 90's with the "new" GPS technology. Also worked with SCORE, ESPN, and BFGoodrich tires.

GPS is mandatory safety equipment now, but when we started SCORE wanted to outlaw it.

Most Baja teams today run LOWRANCE Electronics GPS equipment thanks to my work with BFG and a gentleman named Dave Churchill.

I haven't been back to Baja since 1999 when I left Lowrance, but I still watch and follow the races when I can. I really hated leaving that part of my job - it was a blast!

Just curious if we have any friends in common.

rr64_old · February 4, 2010 at 3:38 AM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

Dan, Is that bracing on the oil pump pickup part of a race Cobra modification as well? A friend of mine has a pickup like that and we are both unsure as to what it is for.

-Fred-

Hi Fred,

Yes. Based on long ago magazine articles and Shelby American correspondence with racers, road racing Cobras had pickup/pump breakage early on so pickups were fully gusseted and a brace was added to dampen out vibrations of the assembly. AN aircraft bolts (safety wired) held it all together. The brace goes to a main cap bolt. I have not figured out what kind of main cap bolt but rumor says it was a truck part something like a 1969 Boss 302 main bolt for windage tray attachment. The head has to be shorter than a 1970 Boss 302 main bolt for a windage tray because I bought one of those and the head is too tall. I have not found a 1969 Boss 302 bolt to test fit, I am told they are shorter.

The pump that I have is said to have left SAI on a brand new GT350 racer. The man that owned the car a long time ago when this pump was removed kept it until I got it. The pump and pickup were still bolted together when I got it if you want to see an image.

I hope to reconstruct/rebuild this pump (new rotor, stator, and valve) and use it. Somewhere in its long idle time it got wet inside so the steel internal parts are ruined except for the spring and shim. I wonder if any of the pump shops that prepare new custom pumps could/would test it for me once it is back together.

I bought a NOS rotor and stator just before Christmas but the USPS managed to get the box soaked, which then fell apart, and then it appears the rotor got bounced off some concrete and was ruined. The whole mess was in a USPS plastic bag (soaking wet) with an apology for any inconvenience printed on the bag. (The USPS has enough “oops” incidents that they have printed salvage bags on hand….never knew that.)

Dan

Edited by - rr64 on 02/04/2010 03:40:35

Edited by - rr64 on 02/04/2010 03:43:08

jwc66k · February 4, 2010 at 12:01 PM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

jwc66k,

Who's Baja 1000 engines?

I supported the Dodge and Ford race teams in the 90's with the "new" GPS technology. Also worked with SCORE, ESPN, and BFGoodrich tires.

GPS is mandatory safety equipment now, but when we started SCORE wanted to outlaw it.

Most Baja teams today run LOWRANCE Electronics GPS equipment thanks to my work with BFG and a gentleman named Dave Churchill.

I haven't been back to Baja since 1999 when I left Lowrance, but I still watch and follow the races when I can. I really hated leaving that part of my job - it was a blast!

Just curious if we have any friends in common.

I built several Baha 1000 engines, all VW, for classes 2, 5 and 16 (classes now replaced by something else). This was in the 1978-79 era. We worked out of a shop in Sunnyvale for just plain folks, no Ford or Dodge factory people around. A "few" cars I worked on finished. The formula "V" stuff was a couple of years earlier. I still drive a Baja around town.

Jim

RalphJr · February 4, 2010 at 1:42 PM

Jim,

Thanks. The VW guys are the real backbone of Baja racing - true racers at heart and TOUGH - you have to be to take the pounding hour after hour in a VW that BAJA dishes out.

I worked with mostly Trophy Truck guys, but did help a few in the Sportsman classes.

I had a lot of fun in my 7 years supporting the GPS efforts for Lowarnce - I have a lifetime of stories and photos.

The Baja 500 or 1000 is definitely a race that should be experienced by any hard core racer or fan.

Ralph

Zed · February 18, 2010 at 2:55 AM

Hi, sorry to here about your pump being ruined in the post. Just some advise for those sending stuff. Always pack the item to keep it dry and to keep it safe from being dropped or squashed whilst in care of the postal service. USPS have bags and letters for damaged items as does Australia Post whom I work for.

What happens in Australia for items to get wet is the mail bags are left in the rain by airline staff (non post office staff) while they load and unload the cargo from the plane.

We then get the mail and have to sort out the mess presented to us i.e. dry out the items and bag it up.

I would imagine the USPS would be in a similar situation to Aussie Post. So always have/ask for your goods to be packaged properly, it is worth the extra $ spent for your items to arrive safely.

Regards Eddie

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