340/420 90psi Oil Pressure During Prime

[YO7_A66]

I started priming my 340/420 yesterday and I was surprised to see the gauge go up as far as 90psi when my drill was set on speed 2. I was expecting more like 60’ish as a guess. The pump is the Melling #M72HV and I am using the Driven BR30 (5W-30, & WIX oil filter, .012" EDM hole in the lifters). I did see oil moving around the lifters during the priming which was my main concern.

I had the valve covers mounted, as I was just trying to get a reference on the oil pressure before installing the intake. I will pull the valve covers tonight to look for oil left over on and around the rockers before I torque the valve covers before install.

Can I move forward and mount the intake with this 90psi oil pressure? I will keep using the WIX filter.
Should I take the time to pull the distributor back out and watch the rockers while priming?


Thanks

 

[furrystump]

If it is a new build, never run before you should see puddles on top of the head. Don’t panic if you don’t. If it is dry, you will want to pull the distributor and prime it again while slowly turning the engine over by hand. It will, at some point line the oil holes up and oil should flow to the head. (Each head gets oil at different point) It will also let you check to see if your lifters are spinning.

 

[Scody21]

Yep. During prime and break in on my 340 with the HV pump, it was 105. Now the high side is 70.

 

[furrystump]

With a drill you are spinning the pump pretty fast. 3000 rpm on the drill is 6000 rpm while running.

 

[YO7_A66]

Thanks guys!
I will plan on pulling the distributor back out and checking for oil on both heads before installing the intake. I did pour BI oil over the rockers and springs, so now I will slow down, and check the prime on the heads too.

Note: I did check for the lifters spinning just after I installed the cam. I marked the lifters and then made a video of them all spinning while I spun the cam.

Thanks again,
D

 

[RustyRatRod]

Depends on the drill speed. Most gear driven type drills like a 1/2 chuck drill spin slowly and have tons of torque. But if it spins pretty fast, there you go.

 

[Syleng1]

Also depends on how tight your bearings are. Tight tolerances will drive up pressure. I’d be more worried if you struggled to see 20psi.

 

[67Dart273]

Also the oil is cold and if you used a pre lube grease on the bearings they will be pretty well "sealed" at that point.

And what Rusty was saying with drill motor speed. The drill RPM is equal to the engine running at 2x that RPM.

 

[YO7_A66]

Good point on the cold oil and I have cam lube and pre lube grease all thru this engine.

I forgot to mention that the 90psi was on both 1 and 2 with my drill. I kept switching back and forth between the two gears as both of my batteries were losing their charge.

I am going to try to get the heads primed tonight but I might use my older electric drill for a more consistent speed.
Thanks again!

 

[YO7_A66]

I just finished priming the heads. When I took the valve covers off, oil was already dripping down the head. So I used another slower electric drill (0-800rpm) and while watching all 16 rockers until they pushed out oil, this drill showed 90psi too.
So the valve covers are back on, its primed, and cleaned up and ready for the intake.
Thanks guys!

 

[DC 340]

If, when you fire the motor, oil pressure is still in that range, I would keep a close eye on it.

I had a newly built 340 with a high pressure? or volume? pump (I don't remember). The oil pressure was on the high side and it buckled the oil filter outward away from mounting surface and blew oil all over my engine compartment and the street. All this 18 miles from home.

In another instance, I lost oil pressure as the pressure was high enough to shear the cotter pin in the oil pressure relief valve (in the pump), leaving the valve constantly open. I had to put a thicker cotter pin in the pump to fix. Stuff happens.

 

[YO7_A66]

DC:
As soon as the break in is complete, I will change the filter and the break in oil. I will then start watching the oil pressure and hope that it comes down a little before or during the test driving. I am assuming that the Isky cam grease and all of the assembly lube are showing up in the oil pressure too. I did not use that grease sparingly, and every time I had to spin the crank/cam (setting lash, checking push rod interference, checking coil binds) I added more of that stuff on each lobe. The Isky grease is some pretty thick stuff.

Thanks for the heads up!