SBC oil pump mod?

[77cruiser]

Does anybody do the anti chatter grooves? Do you notice any difference in the smoothness of the pump?

racingoilpump_part.jpg

[ProPower engines]

Does anybody do the anti chatter grooves? Do you notice any difference in the smoothness of the pump?racingoilpump_part.jpg

Depending on the application. I have seen more steady oil pressure when dynoing engines where the pump does not cavitate internally and the gauge reading is rock steady compared to other stock pumps.

We only use this style of pump in all engines including marine engines which see the most benefit

[engineguyBill]

77Cruiser,
The anti-cavitation grooves were considered to be a real "speed secret" several years ago, but you don't hear much about this anymore. Most important thing is to make sure that there is minimum specified clearance between top of gears, when installed, and the pump cover. This can be measured with a machinist's rule and feeler gauges.

What is the temperature at I Falls today?? High temp at my house is predicted to be about 74 degrees F today . . . . . .

[77cruiser]

I always try to keep the clearance to .002-.0025.
-30 last night heatwave today +10 spring tomorrow +25.

[pamotorman]

i always drilled a .062 diameter hole in the center of the driven gear to make sure it got lubed and set the vertical clearance to .002/.003. also radiused the pump output port to remove the shape edge for a smoother output flow.

[77cruiser]

i always drilled a .062 diameter hole in the center of the driven gear to make sure it got lubed and set the vertical clearance to .002/.003. also radiused the pump output port to remove the shape edge for a smoother output flow.

I do that.

[oldhead]

Big Joe use to say he inlarged a hole in the pumps he used, I would guess the Oil relief exit hole???????? Oldhead

[Schurkey]

I'm no expert in this...but...I never understood why folks carve all these grooves in the pump body.

How do these grooves--which do little more than bleed oil under and over the gears--do anything that more end-clearance wouldn't do? Yet the first thing folks do is tighten-up the end clearance.

I've heard them called "anti-cavitation" grooves, and "pressure-balance" grooves, but never "anti-chatter" grooves.

[Walter R. Malik]

I machine a slightly different version, (with a few other small mods), but, it does help with steadier ignition timing at a steady state and smaller amplitude oil pressure spikes.
Does it help much? Who really knows however, it does no harm.

Most gauges have some sort of internal damping so, an un-dampened gauge is needed to be able to see it there.

[shoedoos]

From personal experience, the slots certainly help to lessen aeration in the oil. Put your pump in a container of oil and hit it with a drill, then cut the slots and do the drill again, night and day difference....