oil pressure problem

[Rob Petrie E395]

Have you pulled some caps and looked at the rods and mains to see how they look and check some clearances? Another thing that comes to mind is this scenario.

Something was not right from the get go (IE not enoughf oil in the pan, pan that could not controll the oil ect) So when you crossed the finish line the pan was already low on oil or the pan could not controll it. You hit the brakes to slow down and whats in the pan goes forward away from the pickup uncovering it and oil pressure went low and hurt one or more bearings.

[Phillip marvetz]

I have had exactly what Rob is desribing. It hurt 1 rod bearing and was very low on pressure once warm at a idle. Never made any noise just lost oil pressure and this on a car with exhaust so I would have heard it knocking. When I dropped the pan the bearings all looked fine but one had lost it's tension in the cap, I almost reused it it looked that good. I put new bearings in with the old pump and it was back to idling hot at 40psi in gear again just new and went all last season like that.

[Mike Taylor 3601]

Your original problem sounded like oil getting away from pickup,Your next problem sounds familiar,you did'nt say what pump you put in when you changed,but I ran into problems w/ 3/4 pickup hex drive pumps that melling has,they idle good and drop pressure when rev'd.I sold several and everyone has been took back out& replaced for that reason,replaced with 5/8 pickup HV melling select pump and fixed it.
It acted like cavatation,but could'nt get to stop tried different pickups,clearances on pickup,overfill w/oil, just switched to 5/8 pickup pump and fixed everytime.
Years ago we used run 3/4 pickup bbc pumps in sbc without any problems,so I don't know why we could'nt get those pumps to work,I remember comparing pumps and could see no difference other than pickup diameter.
Mike Taylor 3601

[Adger Smith]

Take those nice screens out of the drain backs in the block as well as the vent pipes you screwed in the lifter valley. I bet it has a vac pump on it too. The oil rope that builds up around the rotating assy can keep the oil out of the sump. Get a good windage tray & pan combination on it that scrapes the oil back to the sump.
Those long stroke SBC's need the "right" pan and windage control.
Keep in mind your 434 has a lot more movement above the oil pickup than a 327 or 350.

[Reed Granrt]

Originally Posted by Adger Smith

Take those nice screens out of the drain backs in the block as well as the vent pipes you screwed in the lifter valley. I bet it has a vac pump on it too. The oil rope that builds up around the rotating assy can keep the oil out of the sump. Get a good windage tray & pan combination on it that scrapes the oil back to the sump.
Those long stroke SBC's need the "right" pan and windage control.
Keep in mind your 434 has a lot more movement above the oil pickup than a 327 or 350.

Yall better listen to Adger
I just got two 434 SBC off my dyno. Both wet sump, one with vacuum pump other without. Customer furnished both oil pan systems. Both blowed a hole in the oil as RPM went up. We dont run any screens as we have seen this problem a number of years ago. Ya got to get the oil off that rotating assembly. Spend time getting oil back too sump. Ya better look at windage, cause it is for real, both above the crank and below the crank.
reed

[79transam]

my pan has a scraper on it. its for my setup. i havnt tried a windage tray though

[Marine One]

Clarification - A loss of clamp load does not "spin bearings". When you see a spun bearing, you also see it extrude out from the sides. This is not because something was loose, but because everything was tight. In other words, the loose cap and spun bearing is a symptom of a larger problem.

A loss of clamp load will result in a bearing that retains its original width, but flattens out and has "bite / chomp" type witness marks. This is from the cyclic load on the rod journal...open, close, open, close...bite, chomp, bote, chomp....

[Pvt Parts]

Originally Posted by Rob Petrie E395

Have you pulled some caps and looked at the rods and mains to see how they look and check some clearances? Another thing that comes to mind is this scenario.

Something was not right from the get go (IE not enoughf oil in the pan, pan that could not controll the oil ect) So when you crossed the finish line the pan was already low on oil or the pan could not controll it. You hit the brakes to slow down and whats in the pan goes forward away from the pickup uncovering it and oil pressure went low and hurt one or more bearings.

X2

Yeah, I'd be pulling some caps and checking bearings and crank. I had a Z28 that did that very same thing about 3 months after a rebuild with a new crank. I pulled the motor out and apparently the crank had not been tuftrided. It looked like it had 200,000 miles on it. GM warrantied the crank and I was back in business.

[79transam]

i checked the bearings over the winter, just visually when i put the first new pump in. they all still looked brand new. i didnt get this motor in my car until late in the season and it still looked great.