I just realized that since I have a brand new 4-bolt main shortblock that has tight clearances, i probably shouldn't have gotten a high volume pump. I still have time to change it out, so which one should I get? It's going to be an AI 200cc motor and I plan on beating the **** out of it a lot. Would it hurt the motor to put a HV pump in it?

I have a Canton Road Race oil pan, Canton 3/4" 7.5" High Volume pickup and the melling screen.

 

I always thought it was how much a pan would hold worth of oil that was the concern with HV, not the clearances.

 

Trying for some more opinions on this forum?

That's not the whole story. There are plenty of HV pump threads with info.

 

Melling select 10554 - high pressure pump, not high volume.

 

I have a Melling HV with a Canton pan. No problems at all, infact I called and talked to ThunderRacing and they said they don't use anything but HV. There are alot of opinions on this subject, do what you want, but there are several running one or the other.

 

?You can use a HV pump wit the Canton pan if you want. Just don't with a stock pan. OTOH, unless your motor is set up with loose bearing clearances you are just wasting power pumping more oil.

Rich

 

I have loose clearances (.0025 rods/.003+ mains) and have decent pressure with a standard pump and 5w30 oil.

 

If you are seeing good pressure, that implies the pump output is adequate. However, with the somewhat generous clearances, I wouldn't argue against the HV pump but again, NOT with a stock pan. If you are using a stock pan, stick with a stock volume pump with high pressure spring. In 99% of small blocks a HV pump just serves to heat and eat power.

One reason people use to justify the use of a HV pump is high rpm, which completely illogical.The pump output, for practical purposes, already varies linearly with rpm. If the pump produces adequate volume at 2,000rpm, then it will at 8,000rpm. The kicker here though is the bypass. That's why you should use the high pressure spring for a high revver. BTW: why do you think Chevy put a bypass circuit in there in the first place? Because the stock pump ALREADY has excess capacity.

Rich

 

Forgot to mention I have the high pressure spring as well.