High volume oil pump at what clearances?
 

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 :lol:

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. :D Maybe some people more qualified will reply. :)

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

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?

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

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

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

Rich

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.

thanks alot everyone!

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. :)

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.

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

so they can run a HV pump? :shrug:

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.

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

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