Oil pump pickup question

[joedoozer]

Ok here's the deal.

In the final stages of a rebuild and I have a Melling M55HV pump that was in my old motor when it blew up. That pump is high pressure, high volume. I never had an issue with pressure, but needed a new one after the blow up.

I bought a M155HV pump which is standard pressure high volume. I did not realize that the pick up tube on the new pump is a 3/4", and my old pick up does not fit.

I can not use the old pump because the gears are all pitted.

Can I use the pump cover from the old H/P-H/V pump on the new S/P-H/V pump? The covers appear to be identical, and the old one is in nice shape.

The off season budget is planned out to the nickel right now and a new 3/4" pick up costs more than the pump did. The money just isn't there. If I have no options I will will order a new pump, but I am avoiding that if I can. I believe the only difference is the spring, stiffer spring in the older High Pressure pump. Couldn't I just swap springs?

[joedoozer]

From what I understand of oil pumps is taller gears means more volume, and stiffer spring means more pressure. It appears only the spring is the difference in the covers. I really hope I don't get a "thumbs down" on this......haha I would hate to take the pan back off.

[stock car driver]

If you want to use that pump buy a pick up for it.

If you really cant afford a pick up then I guess buy the old style pump and return that pump.

I run the old style pumps but only a m55a which is high pressure. Theres plenty of volume at the rpm we see.

[joedoozer]

I'll just call Melling and ask them.

[fast_crew]

make sure you clean the relief valve and check for burrs, or sticking. I would get the 3/4" pickup myself

[joedoozer]

Talked to Melling today, the only difference in the covers are the pick up tube size.

[stock car driver]

Talked to Melling today, the only difference in the covers are the pick up tube size.

did they tell you why they used a larger pick up on the newer style pump or say wow youve got a great idea there well send you a check. we never thought about taking our new better pump and choking it down with a smaller pick up than we designed it for....

[joedoozer]

He said the only difference between the pumps is the pick up tube size. I told him what I was doing and he agreed that it doesn't make any difference. I posted the response for future reference, if anyone searches for something like this.