Oil Pressure

First off, welcome from Pittsburgh, PA! When you get a chance to fill out your profile, please do so as we might just have a fellow board member here who is in your neighborhood.

Can you elaborate as to which plug you pulled to check for oil pressure? On the L-head four, the oil supply for bypass oil filter should be coming from the tapped oil galley right behind the fuel pump, on the lower left front side of the engine. From the driver's side of the Jeep, locate the engine mounting plate, and the fuel pump. Down behind the pump you should see a 90* fitting that is probably obscured in grease, grime and other unmentionables. The other easy way to find this fitting is to follow the hose from the top of the oil filter canister down to the block.

There is another plug at the rear of the block, down by the bellhousing on the same side of the engine. This is where the oil pressure gauge is normally plumbed in. On both of these ports there should be anywhere from 5-30 lbs of oil pressure, with 30 being mostly wishful thinking.

The third place that you will see external oil lines on an L-head is the oil return coming from the bottom of the oil filter. This is a gravity drain, coming from the bottom of the oil filter housing and draing down onto the cam gears. There is next to no pressure on this line, but it is vital to healthy operation of the engine.

Clear as mud?

Post back with clarification, and we'll git ya runnin' in no time!

 

Yep, it is tapped into the same galley as the front port. Don't run the engine long, but does anything knock when you do run it? Sounds like you may have an oil galley plugged up with crud...

 

Yup, I'm a career Lieutenant on a mid-sized combination force, (67 personnel) 12-1/2 years + 3 -1/2 years prior to that as a volunteer in my hometown.

I'm sure someone else will chime in here, but if that galley is plugged, that is not good news. There could be a whol ehost of issues going on here, ranging from a simple plugged passage up to a set of wasted main & rod bearings (not likely without a knock). The bad news is that in order to clear the passage manually you are likely to induce a bunch of crud into the bearings, where they will do a bunch of damage. The worse news is that in order to clear it all out 100% I think a good tear-down and hot-tanking may be in order.

The only way I can think of to get a good clean-out on that main oil galley is to remove the transmission/transfercase assembly, as well as the flywheel. Then you will have access to the allen pipe plug at the rear of the block where that big oil passage ends. You could then pass a big, long rifle-bore brush through the front galley port back out the rar of the block to clear it out. I think I'd try some stout pipe-cleaner-type instruments through the blocked port first, to see what they bring out.

Oh, and after you do any reaming of the oil galleys, I'd dump a quart of Rislone, marval Mystery Oil or equivalent into it and let it idle for 20-30 minutes before draining and refilling the oil. YMMV!