Low oil pressure question

[Camaro383z]

Well heres the deal. I have a 92 xj with 178k on it and it blew up in the fall on the way home from Haspin Acres. So I decided to do the 4.6 stroker rebuild. I got everything done and running when the jeep is cold the oil pressure is above 40. But after 5 or so min of driving the oil pressure drops below 10 I would guess and you can here a slight ticking from the top end for a split second and then it goes back up again to around 40. The jeep had low oil pressure before it blew up also. Everything in the engine is new, I have a mopar "high volume" oil pump. I really do not want to hurt this engine obviously. I have 6 qts in it. So im confused. I was wondering if it could be something with the distributor driving the oil pump? Not sure this could be a common thing being that the distributor is the only thing I reused basically. Any suggestions would be a big help. Paul

[John]

Have you checked the distributor gear? Oil pickup tube and gasket between pump and block?
John

[Camaro383z]

Yeah that is alright. Would the distributor gear being worn slightly make it do that, cause its not broken or stripped?

[John]

As a little wear is difficult to see. I can't really know, can you get a pic?
John

[tirod]

Change the filter to any better quality one not painted orange.

It's an old complaint, "some" filters have cardboard end caps on the filter media that separate and cause an internal bypass. It comes and goes, causing intermittent oil pressure loss. In my case, I could shut it down, restart, and get pressure back up with no idea when it would happen again. But it would.

The problem started when the first engine threw a rod on the interstate . . .

If you are still having the problem after, it will be cheap and eliminate one source of the symptom.

[John]

Had completely forgotten about that possibility. Neven had it myself, I have ran the Napa gold by wix for ever. A rare one is a cracked galley plug, have even heard of them missing after rebuilds.

John

[stroked'73]

Does it happen EVERY time you drive the jeep? As in every time it runs from cold for about 5 minutes? Or is it just sometimes? If it's all the time and only when you said, it would lead me to think it was something temperature affected - like something happening once it began warming up. Don't have a clue what, but that was my first thought when I read your post. Seems if it was a dizzy gear, it would be a sporadic problem and could happen at any time. Does the engine seem to die or stumble or slow down when this occurs? Have you ruled out the gauge? (just brainstorming...)

[tirod]

Oil pressure senders have been known to go bad. Using a high volume pump is also known to stress the oiling system - the extra volume has to go somewhere, especially when stock bearing clearances were adhered to. High volume pumps are really for race engines with wide clearances that can tolerate more oil at the rings. With stock clearances and no way to get oil out of the system, the oil relief pressure valve could be bypassing. This would definitely occur just after startup when it's still cold. Ergo, low pressure because the valve bypasses.

[John]

They work ok if you drill the oil galley to spray some oil on your camshaft....
John

[Flash]

They work OK if you drill the oil galley to spray some oil on your camshaft....
John

Not to change the subject here but...........that though keep passing thru my mind.

If the rod/cam squirt hole was inlarged......MYBE a HV pump would be a good idea

A race eng my not want that much oil slapping around the crank...........but, 5,000 rpm is hardly a race RPM!

[oletshot]

I believe the pressure relief valve works by releasing the extra pressure above a specific value. For example if it's a 75psi relief valve and you were pumping 85psi the relief valve would dump the extra 10psi and the system would stay at 75 until the oil heated and pressure dropped.

[oletshot]

They work OK if you drill the oil galley to spray some oil on your camshaft....
John

Not to change the subject here but...........that though keep passing thru my mind.

If the rod/cam squirt hole was inlarged......MYBE a HV pump would be a good idea

A race eng my not want that much oil slapping around the crank...........but, 5,000 rpm is hardly a race RPM!

Or maybe with the cam saver lifters. I now want to disassemble and grind flats on my "Chinese" lifters. I say Chinese because they came in an unmarked white box with only a part # written by hand with a Sharpie. They are supposed to be Clevite, but I have my doubts. Damn!
Can someone measure the width across the flat.

[gradon]

So who has drilled their oil galley? I haven't bought the oil pump yet, but from all that I've absorbed, I'm leaning towards the stock pump.

[John]

The stroker in my YJ has a extra spray to the cam gear and #6 cyl intake and exhaust. Drilled from the inside.
John

[gradon]

So why did you choose #6(was this prior to all the cam failures, that tend to happen in the #6 area). Any pic of where to drill, bit diameter, etc.?