Oil pumps

[Robyn]

As many of you may know, I have used/did use a high volume (squirt block) oil pump from a 506 engine in a 929 block (non squirt)

The oil pressure cold (moderate weather) will run 85+ cold running or idle and then slowly fall of to 60 PSI running and 35 idle

I just finished pulling the oil pump drive and such from the DaHoooley engine due to the head gasket issue.

The pump drive shaft was very very difficult to remove from the drive unit.

I am having second thoughts about this practice now.

I will reinstall a standard volume pump when the engine goes back together.\

I dont even want to think about the system pressures if this was used in COLD weather.

I am going to say that this practice is one to avoid.

The standard pump with its flow and pressures are to be used on the non squirt blocks such as the 599 and 929 or any other block in a 6.2/6.5 that does not have the squirters.

Oil pressure in these engines does not need to exceed the 40 PSI max under normal running.

The high pressure could cause other issues in the coolers or lines in due time.

The drive gears on the cam and the pump drive could also take a beating.

Just food for thought.

Missy

[john8662]

some vary too, the pressures you're showing sound different from what I've seen.

I have to agree that in a 6.2 or non spray 6.5 I'd use the standard pump, plus it's a lot cheaper.

I should be close to having our pumps tested, a buddy of mine that has a machine shop has been experimenting with testing the regulator setups on oil pumps and why some are so inconsistent. He did find some interesting things out, that I cannot really share. The end result is that he has a fix that's pretty simple and can calibrate them better than they come. I've been meaning to give him both a standard volume and HO pump. He really wants one of the HV, I just had to wait until I had a used one to give away.

J

[jerry598]

Always feel a slight bit of discomfort when I read posts like this. Using a high volume pump would be the 3rd mistake I made on my recent rebuild, along with boring it out to .040 OS and not installing the aftermarket braided steel oil cooler lines.

I really can't see why the higher pressure would cause any serious wear on the cam/pump drive gears. But I am going to change to 5W-40 oil for the colder months now.

Sorry to hear about your engine, Robyn. Kinda glad, though, that it wasn't due to a catastrophic failure like a cylinder wall crack or an L&S insert letting go.

[Robyn]

Having a cooler and lines that were/are designed for the higher pressure is really the big issue.

The pump is not going to care really. The use of the 5-40 oil will make a world of difference in that low temp startup pressure.

The one worry I had was cam gear wear, but after looking at the parts. Probably just me being anal was all as I found little if any unusual wear.

The cam looks fine as does the pump drive gear too.

Probably the only real worry spot is the stock cooler lines and snap connectors.

The only reason GM went to the larger pump was to cover the huge internal oil losses due to the 8 squirt nozzles bleeding away.

I only used the HO pump because I had it and it was in great shape.

Thats a fairly large $$$$ outlay just because.

The pump thats goin g back on this engine came from the 94 Burb 6.5 I built.
I had a new pump that I got real cheap off ebay and used it on the Burb.

Took the old pump apart and its fine, stuffed it back together and its going on the DaHooooley 6.2 engine.

Should be perfect.

Have fun

Missy

[rustyk]

As long as the relief valve is working properly, the HO pump will hurt nothing - and the volume will approximate that of the standard pump.

[Robyn]

My only concern is the fact that during cold startup, the pressure goes to 75-80 PSI and this is with the thing at an idle.

The relief valve can't dump it fast enough so the pressure goes up quite a bit.

This will not hurt the engine at all but my concern was the cooler lines, the connectors and possibly the filter or the cooler itself.

Witha system that was designed to run 40 PSI and then jumping it to double that. ??????.

The bearings and internals could care less. The rear seal is well drained on the rear main, so there is not an issue there.

Nothing is close to the front cover seal so its fine.

The only other thing I was worried about was the pressure on the pumps little hex drive shaft.

Even the HO Pumps were designed and sized to provide about 40 PSI and not 80, just move a lot of oil.


Missy