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Pump the oil thru a new engine

gmcelroy

NAXJA Forum User
Location
CA
I am rebuilding a Jeep 4.0.....How do you pump the oil thru the engine before you start it.......It appears that the oil pump is hooked up to the distributor and the cam.......So if you spin the distributor, you are turning the oil pump AND the cam which is turning the engine over.....Therefore, my conclusion is that the only way to do this is to pull the coil wire and turn it over with the starter.....Any thoughts?
 
Pumping oil through the engine? You'll need an oil pump priming rod that can be chucked into a drill motor.

While finding one for an AMC I6 is not common, finding one for small block Chevvy is. I found a SBC oil pump priming rod with a removable guide sleeve, removed the sleeve, and used that. I'm not sure if the guide sleeve would have fit over the oil pump drive nub - it probably would have - but I wasn't taking chances.

The one I got was a "tang" drive (it may have been SB Ford - it's been years since I bought the thing...) but it looked like a flat screwdriver with a sleeve around the end. The SBChevvy may use a "hex" rod instead of a "tang" drive - I'd have to check to be sure.

You could probably also make one out of a largish flat screwdriver, if you were in a pinch.

To use: remove the distributor and look down the hole. You'll see a large nub with a slot in it - that's the oil pump drive. Insert the priming rod, and spin with a drill motor.

Ideally, you'll want to plug in a mechancial oil pressure gage (where you can see it) - and make sure you can sustain oil pressure for a minimum of two full minutes.

5-90
 
If you use enough assembly lube on all the parts that need it while you're rebuilding the only thing you need to do is pack the oil pump with grease or make sure it is filled with oil so it primes itself when you fire the engine for the first time....keep a good eye on the oil psi gauge it doesn't build pressure immediately shut her down fast and find out why.

All this is irrelevant if you already have the oil pan bolted up,though......
 
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If you can lay your hands on a spare 4.0L dist, you can grind the teeth that run on the cam off and spin the dist with a drill (that's how I do mine)


PS: Do NOT use a high volume pump in an AMC 6 because the tabs are too long and they will push the dist up till the cam gear wipes out.
 
My neihbor just pieced together a 4.0 for a couple of different engines. He just put a standard screw driver bit in an electric drill and spun the oil pump shaft till oil started to pump oul onto the rocker arms. I'd rotate the engine while doing this. Then he turned over the engine with the coil unpluged, till it shown oil pressure.
Tom
 
I actually have a gizmo thats made for that purpose of firing up new motors.
It's a pressurized vessel, a tank a little smaller than a propane tank, and you put a few quarts of oil in it, pressurize it with air, hook it up to an oil passage-usually by removing the oil pressure switch/sending unit, and then open the valve on the tank.
Thats the deluxe method. Spinning the oil pump with a screwdriver works just as well.
 
gmcelroy said:
I am rebuilding a Jeep 4.0.....How do you pump the oil thru the engine before you start it.......It appears that the oil pump is hooked up to the distributor and the cam.......So if you spin the distributor, you are turning the oil pump AND the cam which is turning the engine over.....Therefore, my conclusion is that the only way to do this is to pull the coil wire and turn it over with the starter.....Any thoughts?


Do not run the starter and turn the engine over without proper priming, you're just asking to wipe bearings. Cranking without ignition and oil system priming are not the same thing.
 
Autozone has a spinner for less than $10
 
I did this some years ago by taking an old oil burner, hooking a little tank to the inlet, and plumbing the output through the oil pressure switch hole. I pumped a couple of quarts through, turning the engine over a few times after it was primed. The only real advantage of this over spinning the oil pump is that you can do it with the pan off or the plug out, and it will flush without recirculating any of the crud. It can be a quick way also of checking for bearing problems in an older engine if you take the pan off. You can compare the rate at which the bearings dump out oil. Using the oil pump is probably just as good, but it would probably be worthwhile to sacrifice a cheap oil filter just in case you flush through any chips or abrasive junk. I would certainly recommend that if you've had a ring job, to flush out any honing residue or chips from ridge reaming.
 
Well, I just did what the manual said and packed the oil pump before installing with Vaseline. Then, once the engine was in place, we cranked it over with the valve cover off (coil wire off) and watched to oil come to the top of the valve rods. Once all were sure we had oil pumping, we buttoned down the valve cover and fired her up.

Worked fine on the three engines we've done so far.
 
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