Jeep Strokers

Started this newly built 4.6 roller cam motor up and had 55+ psi oil pressure but hot idle pressure was so low the check gauges light came on. Called the owner of the machine shop. He asked if the gauge would go up with rpms and was the motor making any weird noises. I said no weird noises and the pressure jumps right up, he said not to worry about it. I did drive it and put a mechanical gauge on it and the factory gauge (on a 97 TJ) reads consistent. Motor ran strong with no weird noises but the oil pressue was about 5 psi at hot idle. I changed the oil from SAE 30 to 10w-40, pressure didn't change significantly. I drove it to work (45 minutes) and hot idle was 3 or 4 psi. I called the machinist (instead of the shop owner) and he didn't like the low oil pressures. We thought the pressure drop may have been due to the large grooves in the roller lifters made by 505 performance (who didn't return my email but maybe he didn't get it). Anyway, the plan was to change to a HV oil pump and see if things improved. When I took the oil pan off, the center 2 cam bearings look like this:



What is causing the bearings to "ooze" out the sides like that? I'm guessing the oil film would decrease at low rpm allowing the cam to machine away the bearing. I'll be showing these pics to the machinist tomorrow. What do you guys think?

I've been through that twice. In my case the only problem I found in the end was the pick up tube for the oil pump didn't have a good fit and was easily removed from the pump. On break in the oil pressure would be good.. however with in less than 100 miles the oil pressure would drop to around 10 psi. My lifters were also noisy and didn't quiet down until the engine had been drive for 30 minutes or so. What I think was happening is that that not so tight fitting pickup would pull in air when the engine was cold and the oil was thick. After the oil got hot it pulled in less air so that is why the lifters quieted down.

What were your clearances like? Do you remember if you installed the front oil gallery plug in the block, located behind the cam gear?

Because I was up to my eyeballs in my son's racing program, I let the machine shop blueprint and assemble the motor. I didn't go behind them and check clearances. Lesson learned but how would've I checked the clearance on the cam bearings if I didn't have a bore gauge? Maybe telescoping gauges and then mic them?

I'll be pulling the motor tomorrow...

I would be more concerned about the main and rod bearing clearance being too large and causing the low oil pressure.

I'll plastigauge the bottom end before taking the block to the machine shop. My guess is the grooves in the roller lifters are the culprit. They are huge and look like I took a whizwheel (abrasive disc on a die grinder) and did it myself. I've got a bad feeling about how this is going to play out; I hope I'm wrong...

so you used the 505 roller cam?

Hey guys sorry to but in i am using the 505 perf roller cam with the grooved lifters and my oil pressure is about 70psi in when i first crank it and about 35psi in this hot south texas heat.im using the melling hv with about .02 to .025 rod and main bearing clearance. I think the cam bearing peeling out like thats the prob ,pull that motor back down because now you probally have metal particles in throughout the oil passages.i really dont think its the lifters causing the oil pressure problem.

Scalper,

Do you remember how wide and deep the grooves were in your lifters? Also, what made you decide to use the HV oil pump from the start (505 recommendation)?

If my lifter grooves were .06 wide and .06 deep, that would give a .06 sq. in. hole. Multiply that times 12 lifters and the net effect is having an additional .72" sq. in. hole bleeding off oil. I may not be thinking about this correctly so, anybody, feel free to set the record straight.

Shawnxj - it is the mildest 505 roller.

i think you might be close on the general idea, but the math is a little off. it actually works out to .0036 per lifter and .0432 total

mains checked out at .002 and were very consistent - the rods checked out where the readings were more than .0015 but less than .002. The numbers are in line with the factory service manual's preferred clearance numbers.

amcinstaller, agreed on your numbers, I don't know what I was thinking last night...

the motor is back at the machine shop, will post updates as they're available

Did you remove the pickup from the oil pump yet? If so, how easy did it come out?

I unbolted the tab to see if I could swivel it but it was tight. I was running low on time so I had to button it up and hit the road.

Anybody ever heard of a high volume oil pump running the pan dry while running down the highway at 65 or 70 mph? The shop owner is concerned but his experience is with chevy muscle and I can see how those top ends would trap oil. The machinist who is a jeeper isn't as concerned. Matter of fact, he was finishing up a 4.2 that had a clifford cam and fuel injection.

basscat to answer your question those grooves in the lifters were about .06 deep and wide give or take. Zach at 505 did not recomend the hv i just figure id use it just in case the grooved lifters caused a oil pressure problem.i opened up a the oil return holes and im running a yosura/johnson crank scraper so im not worried about sucking the pan dry.

Basscat, I would mic the journals and not totaly rely on plastigauge in this insantance. In particular, check journals from end-to-end and 90 degrees offset (mains and throws). I was just re-reading SilverXJ's build thread and his post on HESCO's forum, and he mentioned Lee said his crank grind was not so good. I think there was an issue with taper, so that could cause oil to "bleed out" before it has a chance to be forced through all of the passages to reach cam bearings. The oil is going to take the path of least resisitance, and a tapered journal will allow excess bleed-off..... Journal eccentricity (90 degree-offset check) will do the same.

I don't think a taper would cause the bleed out. It would have to be a very serious taper for it to reduce oil pressure significantly.