[Sun Tuned]

As it pertains to this thread, I’m going to share what I’ve found in the last 4 Pontiacs engines I’ve built in this last year.

The first 2 were both 455’s. What I would consider higher end of the spectrum builds. Kre or edelbrock 325 cnc type head builds. Block end of the deal were both stock cranks with nothing more than eagle H Beam rods and lightweight normal 2 relief pistons. Basically the same block we all are putting together.

Both these guys were in a bit of a hurry, so I got them to order already blueprinted oil pumps from Butler. Now as I understand this these are Schuman pumps? In other words they come to butler already supposed to be fixed and ready to go. 235.00 each I think they were. And they were clean and looked the part anyhow.

Put both in and they went together about 4 weeks apart. Both were 60 lb pumps. Crank clearances on these two builds were .002 on the rods and .0025 on the mains, endplay was .006 on both. Thrust not touched , I got a thing about that. Rod dude clearance in both was if memory serves me correctly right at .018 to .020 .Lifter bores look real good …all that.

With 30W break in oil both had great oil pressure cold right at 65-70 lbs. however when at normal hot idle we looking at 10-15. The one was just a bit higher. By about 5 lbs.

This bothered the hell out of me because I’ve never built an engine with hot idle that low. Until these two I’ve never built an engine I had not prepped the oil pump myself either.

Fast forward about 2500 miles and the one guy decides we pull this engine and sort what’s going on and I agreed. Here’s what we found…

The pump that’s supposed to be “blueprinted “ has gear to pump body clearance of .004. But the biggest issue I found was the bypass ball would not completely seal on its seat. I sprayed a column of carb cleaner on top and watched it literally run right out the bottom of the seat nearly as fast as I sprayed it in.

After working on that for about 15 mins I got it to hold the liquid above the ball under the balls own weight. Put it back together with .0015 clearance. Put it back in car and now hot idle is rock steady at 35, that’s where I’m used to seeing em at.

We’ve since fixed the other one with same results.

So the last 2 I’ve done I just bought standard Melling pumps like I’ve always done and just did it myself.
Have not had first ussue that way. But I will tell you the last two pumps leaked at the check ball seat as well. It looks ok enough. But if you put carb cleaners on top of the ball I’d highly suggest monkeying either that till it’s dry underneath before putting it in service.

[chiphead]

Originally Posted by Sun Tuned

Both these guys were in a bit of a hurry, so I got them to order already blueprinted oil pumps from Butler. Now as I understand this these are Schuman pumps? In other words they come to butler already supposed to be fixed and ready to go. 235.00 each I think they were. And they were clean and looked the part anyhow.

There have been several guys on the pontiac FB groups recently complaining about low idle oil pressure in new motors. I ask where they got the pump and if they took it apart and blueprinted it. The answer every time is " I got it from Butler so I assumed it was good."

A M54DS on Summit is $91 as of today. Somebody is making bank on these "boutique" pumps that still have the same issues as a M54DS.

[Sun Tuned]

I agree about that.

Thing is, in both cases, both put out 65 lbs + when running a drill priming tool. Mine just happens to be a stock points distributor, driven by a Milwaukee electric 1/2” drill.
So likely 350 rpm.

The leaking checkball was the tell tale for me. When hot and the oil thins out ,it bleeds off just enough to have a controlled leak abd oil pressure at idle goes in the you know where.

Now the whole time….i gotta think, surely folks haven’t been using these out of the box, they have to be doing the required extra and not seeing ussue. That’s what happened on the 2 I redid, run fine now with no issue.

So if they say they using em in engines out of the box, either someone not paying attention or I’m the only idiot that got not one but TWO in a row that were culls.

Bottom line : check your stuff period. Save yourself a bunch of extra work.