wierd oiling system problem, need help.

[dusterbd]

okk. quick rundown:
55 psi, hot, at cruising speed
about 25 hot at idle.
rev it in nuetral, oil pressure is slow to respond, but does so.
when taking off at a stoplight, the oil pressure drops to dang near zero, then picks back up vvery slowly. doesnt matter if i dump it or baby it.
pulled the pan, the pickup was loose for some reason. no bearing problems, no clogged screen, no loose pump, no stripped pump drive.
so my question is, what in gods name is making the pressure drop? it seems to me that the looose pickup would have done it from the start, so what gives?
im looking for any suggestions whatsoever, ccause this worries me.
thanks
mike

[lenweiler]

Is there excessive top-end noise, ie lifters? I had a fella in trouble with about the same simptoms, and it turned out to be excessive lifter to bore clearance. The pump may have to much clearance in the body which will also cause the same problems. You may have to pull the pan again and check with a feeler guage. Len

[sanborn]

You may have some trash in the oil pressure gauge pickup. Try using a different oil pressure gauge to verify your current gauge is correct.

[Tarrbabe]

The loose pick-up caused air to be pulled into the oil stream. The pick-up will have to be replaced and I would most likely replace the pump too. Make sure the new pick-up is clean, tight and installed properly. I agree with sanborn about the guage, the slow movements could be from sucking air but I'd check the guage to make sure. The chances are too great to take.

[PRO]

you didnt say whether BB or SB but you may have a crack in the threaded portion of the pickup if BB or a gap in the pickup to pump mating surface or blown gasket if SB,also you may have too much clearance between the bottom of the pan and the p/u,look thru the drain plug you should have 1/2" max,Ive also seen on SB's the pump housing crack if it wasnt fully seated before it was torqued..........PRO.....

[6Cuda6]

I would agree with PRO, check your pick-up to pan clearance...stick a wad of play dough to the bottom edge of the pick up and put pan back on motor.....once seated lower pan and check clearance...should be no more than 1/2 inch.....does your pick up have a plate along with the screen? is it facing the proper way [not towards the back]

[73Challenger11@]

I always thought the pickup should be right on the bottom of the pan with no gap....

[gotcha]

Duster....had a similar problem and it turned out to be a mismatched oil pan and pickup. This was on a race 360 and when the pan was installed, the pickup kinda rode up on the sump cocking it a little bit sideways. Carried tons of oil pressure at idle and cruise but when you nailed it, it went to zero. The guys are right in that there is too much at stake to risk it. Has the engine been apart recently, a fresh rebuild, or did this just start happening?

[dusterbd]

sorry the reply took so long. ive spent 3 sixteen hour days wrenching, and then helped my dad build a garage. the motor is fairly fresh, and it was built by chrysler (50,000 miles). i checked the gauge with a different one, pulled the pump apart and checked for cracks, and finally found the poblem: just what happened to gotcha. it was kickd almost straight sideways. it sucked. bbut anyway, i have the car back together now, and its on the road. thanks for all the help.
mike