oil pump selection

-
Sedanman

Sedanman

67-9 Valiant specialist
Joined
Apr 3, 2009
Messages
8,536
Reaction score
595
Location
chicago Il
Is it better to have a high pressure oil pump for roller lifter engines or HV? I have a new HV in stock
 
It is now but it won't be. I will be boring it out (no more than 0.30),switching cams,upping the compression to about 10.1. It has dished std bore now.
 
If you use the HV pump make sure you get a Intermediate shaft with a harden tip.....
 
Stock replacement, Melling M72.
But really...........................................................................................figure out the final clearances before you "decide" what you need.
 
Haven't used a HV pump in decades. Never an issue.
 
dave hughs said he wasn`t a fan of hi volume pumps in a big block. I do have one in mine==========
 
Looks like I have a m72 stock pump. I could have sworn it was a HV.
 
The engine oil pressure at mid or high RPM's will not be determined by the pump type but by the pressure relief spring; both pumps will put out enough volume to build the pressure past the relief spring setting at those RPM's so the engine will see no oiling difference between the 2 pumps.

BTW, there are 2 springs for the SBM pumps: mid 50's and low 70's psi. The higher one has slightly thicker spring wire but looks the same otherwise. Either one can be in either pump, and KK reports that the Mellings use the higher psi spring in both STD and HV types, so you very likely have the higher pressure spring in your M72.

The only place there is a difference in actual oiling is at idle to mid RPM's. The HV pump will keep better pressure there, and build it faster as the RPM's come up. But it is not a huge difference in the SBM pumps as the HV impeller is only 20% taller than the STD pump. So either one will work for most SBM builds. (Hence the reports of consistent success with both from experienced people.) Other pump types in other engines have much bigger HV sizes vs. STD, so info for other HV pump types cannot be applied generally to SBM HV pump.

IMHO, I'd use what you have unless you are running loose main and rod clearances for any reason; in that case, the HV pump will give better pressures at idle and low RPM. You have a good quality pump either way. And, I don't know that rollers take any more oil than non-rollers.
 
A friend swapped a Magnum in his 68 valiant and said he used a HP pump instead of a HV. I assume he did that because of the roller set up?
 
Sedanman said:
A friend swapped a Magnum in his 68 valiant and said he used a HP pump instead of a HV. I assume he did that because of the roller set up?
Click to expand...
There is not explicitly an HP pump for the SBM.... you can put the higher pressure relief spring in either the STD or HV pumps and each will become 'HP'. The roller and non-roller pumps all interchangae, but I cannot tell you if the roller engine oil pumps all came with the higher pressure spring; you have it anyway if you have a Melling pump.

BTW, look at you pump and see if the casting has M72 or M72HV on it.
 
Sedanman said:
M72 on the box
Click to expand...
I'd see if it was marked on the casting. Yes, the M72 is the Melling standard pump housing. M72HV is the Melling HV housing, which is just a little bit taller but the same shape. These are the only 2 Melling PN's for SBM pumps.

As KK has mentioned in other posts, all Mellings come with the 72 psi relief spring.
 
You must log in or register to reply here.
-

Back
Top