oil pump

[floppyfoot]

Running a .040 over 350, 4 bolt main, scat crank, crower 6" rods, J&E pistons, Dart Eagle SS heads, Eldb. intake and 4412 Holley, over the top headers out the right side. What oil pump is suggested? Was running a Melling HV pump. Oil pressure goes to 100# on start up. It runs around 75 when under power. Tearing up dist. gears and timing chain. An engine builder said to get that pump out and use a stock 69 Z-28 oil pump. The timing chain has the thrust bearing and cam button, it is from Summit. The engine pulls real strong all the way through the power range. Used that stock pump in another engine and it runs 65# when racing and around 40# at idle.

[js11]

If you are running a reclaimed block (i.e., a block that does not have priority main oiling) an HV pump is still a good idea. HV55 Mellings are fine, although they changed the casting lately (weaker at the base) and changed that number to 10550 or something like that. Their big block pump designed for small block applicaitions is as good as the 555, only not as rough on gears (10990, i think). Go to the Melling website to verify. The Melling HV555 that I used in the past did chew up the distributor gear and oil pump rod (they are notorious for that). Caveat: I did have a motor builder inform me that proper distributor/button/cam alignment will do much to solve that. If you have priority main block, the Melling 10552 (10% more), or 10554 (standard) will work.

Perhaps some motor builders can give you a more complete/better answer. Fellas....?

[Lizardracing]

What oil weight?

[Krooser]

In years past I've used HV pumps… back in the early 80's we even used a 100# spring in our Ford Cleveland's to keep them alive.

Now I believe you only need a standard oil pump unless you have bearing clearances that require a HV pump. Our engine guy told us the same thing… he's built 100's of oval track and drag motors with a std. SBC pump.

[floppyfoot]

20W-50 racing oil

[dereksehi]

It also depends how much bearing clearance you are running most of the race engines we build in our shop we use the HV pumps on the 351 fords and 350 chevys

[c.mac.4]

any thoughts on preferences between using thinner oils & high pressure vs. 20w50 and a std pump?

[perfconn]

You never need a high pressure pump on anything.High volume is what cools the bearings not high pressure.Only problem with high volume is you can pump the oilpan dry if you don't have good oil drainback.That problem is easily corrected by proper block and head preparation.

[Lizardracing]

It also needs to be said if you increase flow without decreasing the restriction, pressure will go up.
So a HV pump will naturally have higher pressure all else being the same.

[ford396]

Lighter oil will drop pressure and still offer you the protection you need in a steel block with 4412.

[floppyfoot]

We use a 7 qt. oil pan. The engine builder I am referring to says the cam is actually twisting because of the oil pump. He says it is robbing power because it is actually retarding the cam timing on the rear cylinders and is costing app. 20 HP.

[Krooser]

I'd also ditch the Summit timing set and buy something with a good JwiS German chain…. top line Cloyes or Rollmaster. That cheap chain is probably stretched already.

[floppyfoot]

There is no so much stretch in the chains but the rollers are coming apart.

[floppyfoot]

This is the same chain and gearsthat the late models in our area are using.