I thought i remember a while back someone saying high volume pressure pumps were bad?? I think it's because the put all the oil on the valvetrain and leave little in the pan. I was wondering how do you chose a good pump....or better yet what would be a good pump for this combo


LE2 heads
LE2 cam spun to 6500
stock crank
Eagle SiR I beams
Speed pro forged pistons

 

There's high volume pumps, and there's high pressure pumps.... and I guess someone might make a "high volume pressure pump"....

The stock pump is fine. If you have a "built" engine, and the clearances were set to support it, a high pressure spring in a blueprinted stock pump is all you need. I've seen this work on LT1 engines ranging to 1,125HP. And using the stock oil pan.

 

For your combo, an OEM-replacement Melling pump with the white spring would be sufficient. The white spring is part number 3848911.

 

I completely agree.

Rich

 

I remember someone saying you can actually lose power by going with a HV or HP oil pump...is this true?

 

The high volume pump gets it's high volume by haveing a deeper (longer) gear to move the oil. It takes more effort to move the larger gear. I don't know if there is any documentation on how much more effort is required. IMO, if the stock flow pump is sufficient in the example given a couple of posts up, why is the HV necessary?

 

I think many people on here started thinking about high volume pumps as a fix for oil pressure problems. If you've been on this board for long enough you've probably seen multiple threads about losing oil pressure at full throttle in the upper RPM range. Some people say it's oil pump cavitation, some have other names for it. I guess it seems logical, if you are experiencing those symptoms then replace your stock pump with one that moves more oil, or operates at a higher pressure.

I bought a high pressure oil pump a while ago, and after reading some opinions on here don't think I'll use it. It's a Melling 555HV. If anyones wants it PM me.

 

I had a builder tell me recently that whether you use a high-volume pump or not should be determined by your bearing clearances. I asked specifically because of some of the debate on this forum. His opinion is that if you have tight clearances, you don't need it, but if you're running looser clearances, you should consider a high-volume or high-pressure pump. So, I'd think it kind of depends on your setup. My clearances are running on the loose end of tolerances, so I've installed a HV pump.

 

Could a stock replacement Melling oil pump be used on a 355 rebuilt with hypereutectic pistons, stock prepped/polished crank, etc?

 

If a stock type pump will work on an 1125 hp engine, it should work on yours.

 

The reason i ask is because the summit LT1 kit comes with a high volume pump. I just don't want to run something that might cause problems.

 

I know i don't need it, i just ask because it comes in the kit.....i would preferably take a stock brand new one. But that is what comes in the kit, so i was wondering if i should buy a stock volume to replace it.

 

I purchased the same kit and I haven't heard anything bad about the pump that comes with the kit. I am still in the process of collecting all the required engine parts, so my engine isn't built yet. But I plan on using the pump that comes with the kit. Check my sig for my engine plans.

I just need the crank/cam and I can throw this thing together.

 

 

What is the Melling PN for the stock replacment?