Low compression on rebuilt 440

[Moparmayhem]

We have a rebuilt 440, .010 over new pistons and rings, with new heads, lapped valves, mild cam, and hyd lifters.
We rebuilt this a couple years ago, (I know, not a good thing) and kept priming the engine with a drill to keep everything oiled.
It is now mounted on our run stand and getting ready to fire it up.
We checked the compression by turning it over by hand and are only getting around 50psi.
I'm hoping it's because the rings aren't seated yet and the lifters have bleed out the oil we primed them with originally.
Can the installed lifters be primed somehow, or is that just a running fix?
Any help / suggestions is appreciated.

Thank you in advance

 

[WileE]

You just prime the engine with the drill, hand rotate a few times, then fire it up and break-in the cam.

 

[INTMD8]

compression check turning it over by hand? Have you tried checking it while using the starter?

 

[1967coronet]

compression check turning it over by hand? Have you tried checking it while using the starter?

I wasn't going to say anything and let him get some exercise .

 

[Moparmayhem]

Yep we just got it mounted on the run stand, turning over by hand, starter coming soon and currently looking for a flywheel to get it started.
We were curious and just wanted get a first check.

 

[Moparmayhem]

It is a workout that's for sure

 

[68-500]

Check it when you get the stater on it. It maybe lowish until rings seat after run in.

 

[Moparmayhem]

Yeah that's what I will do is wait, might be pushing the "Oh Sh*t" button a little early.

Thanks everyone

 

[INTMD8]

I'm guessing the results will be a bit different unless you can crank it over at least 200rpm by hand.

 

[khryslerkid]

...and with the the throttle blades wide open.

 

[RemCharger]

...and with the the throttle blades wide open.

But don't have to put it on a battery charger.

 

[dvw]

Cranking pressure is a function of compression ratio, cam timing, and cranking speed. Changing any one of these three will affect the number. As long as the cam is installed correctly and the numbers are even it is what it is. No way you would see anywhere nomal numbers turning by hand.
Doug

 

[DPeltz]

Agree, hand cranking will never get correct information.

 

[Moparmayhem]

No carb on it yet.
Alright, That's what I was thinking but wanted to be sure, I feel better, now I can't wait to here it for the first time.

 

[RemCharger]

The sad part is going that long and that many rotations wiping all the cam lube off. "Pre oiling" doesn't resolve that.

 

[70bigblockdodge]

I'm surprised he got 50 by hand.

 

[Kern Dog]

We have a rebuilt 440, .010 over....

Where the heck did you find .010 over pistons? I have never heard of any oversize pistons below .020 over.

 

[oldkimmer]

I had a 383 with 11.5-1 pistons and a .550 lift hyd cam. It has 60 psi when I cranked it by hand. I was just curious. After run in it had 200 psi. Kim

 

[Moparmayhem]

My Bad, you are correct Kern Dog .020 Over

 

[a70duster]

Yep we just got it mounted on the run stand, turning over by hand, starter coming soon and currently looking for a flywheel to get it started.
We were curious and just wanted get a first check.

I'll be doing this in a month or so. I've thought about taking an old torque converter and cut off most of the converter so that only the ring gear and fllexplate mounts are left.

Anybody try this?