johnnyb

I checked the clearances on my 355 and the mains are .0025 and the rods are .0027. The guy at the machine shop told me today to run 20w-50 with a hv oil pump. Is the HV oil pump necessary with the clearances i have? I have the stock pan and i have heard of horror stories with the HV pump. so it would be real nice if it wasnt necessary to get the high volume pump and a larger pan

shoebox

Thicker oil and an HV pump sound like a recipie for a stripped pump drive gear. You already know not to run a stock pan with the HV pump. i don't think your clearances are that far out, but I also do not build engines for a living. Maybe some people more qualified will reply.

maverickmk

stock pump if you stay with the stock pan, if you have to have a HV pump then get a larger pan and I would not go any thicker than 10W30, like shoebox said "it's a recipe for disaster" - but that's just my opinion - do a search on high volume oil pump and you will find a plethora of information

johnnyb

I know not to use the hv pump with the stock pan. But is 20w-50 with the regular pump going to be enough with the clearances i have?

Injuneer

Stock pump.... with some "blueprinting", may be the best solution:

http://www.gofastnews.com/board/tech...ower-mods.html

rskrause

Stock pump, stock pan, 10W-30 will be fine unless i you are using a big-time power adder.

Rich

jclark311

I have pretty much the same setup, use a stock pump with the GM White Spring, weld the pickup tube on, and run 10w30, when i start mine i have 50lbs of oil pressure when its hot, at idle i still have 25.

johnnyb

thanks alot everyone!

marshall93z

Stock pump with "white" spring... .003 on the mains and .0022-.0025 on the rods. ~30 psi hot at idle with 10w-40. Getting ready to switch to 10w-30, so probably around 20psi then.

RACEON

Mellings M55 (circa 2001) 5/8 tube, stock pan, 5W-40 with Orange Canton spring. 80 psi cold (Hawaii Cold, 80 degrees) 40-50 psi at idle warm. This is a engine with very similar clearances.
Changing spring to Mellings Yellow. See what happens next week.

The_Bishop

Why does everyone insist on larger than stock clearances? It's simply not necessary.

maverickmk

so they can run a HV pump?

96capricemgr

One of the Impala guys just had the drive strip, he was using a melling 10552, this is listed as being slightly higher voume than stock, but I am sure that is not compared to a stock LT1 pump, so I am not sure if we should call it "HV" or not.

rskrause

Some engine builders like bigger clearances for very hi-po motors. The idea is that there is more deflection and that a thicker oil film will minimize metal to metal contact under these circumstances. That's they way my machine shop does it and it makes sense to me. I can't say if it's true or not though.

Rich

87Aerocoupe

Is there any solution to the cracked and striped oil pump drives, is there a billet or stronger alternative?