Robbie Wilson

So I blew a head gasket a while back because I neglected a bad water pump. Anyway the car's temp guage was broken from when I installed longtubes (ripped it off trying to get the stock manifolds out). So basically I put the engine through hell and back and it probably saw over 260 degrees.

The car one day suddenly lost all oil pressure and wanted to shut down by itself but I Had to drive it home still. pressure was regained after reving it over 1500 or so but something really scary was happening below 1500 or idleing so hot.

I swear I could hear the crank scuffing something near the bottom of the oilpan towards the back of the engine. Its a wierd sound. Its not a spun rod bearing because there is no rod knocking. Its more of a scuffing noise.

SO now I got the head gaskets replaced and it felt great. got everything machined and temps were good but after running WOT maybe 5-7 times in a row. Just wanted to make sure the shop didn't **** something up. WHen I hit the brakes or went into reverse (automatic) oil pressure wanted to drop to zero and the car wanted to stumble, idle rough or die. Sometimes I would hear the familer scuff that scares the **** out of me and sometimes I don't.

After letting it sit all night I cold started it and now oil pressure was through the roof. like 3/4 at the guage. OIl pressure seems fine while cold, after driving around it goes to about 50psi-60psi and stays there while under load. AFTER really warming up for a long time or an extended drive it drops a little bit and eventually arrives at 20psi idle and then fluctuates between 20-50 or so depending on load.

But what the hell... I mean, Are my bearings bad or not? I can't really tell but I hate it now because I am scared to drive my car and I put a lot of money and time in this car because I love it, but I can't afford to rebuild the engine right now. I can get a video but if I drive like a sane normal person there is no problem. Its only if I am racing then I see the problem.

Could this be ICM? I think the plug that goes from the opti to the icm got some of the white insulation borken off and jammed in there. I couldn't get it all out back when I had to unplug it to replace my water pump. I hope my crank and bearings are fine otherwise I am screwed. The mystery "scuffing noise" is keeping me awake at night! LOL

for some reason I want to keep the lt1 too. Idk why but I like it better than the ls1. I've driven both and the sound and feeling from the lt1 it just better. I like the tourque curve better too stock for stock. (no cams for either way anway).

4K+Converter

I had a problem like that on a different car. It didn't have the oil pressure involvement either.

My car would go full lean, stumble at idle and die or seriously try to. It would do that after a WOT run or after a long cruise on the highway.

What it turned out to be was a faulty connection to the throttle position sensor.

You might want to check things in your engine harness. I know I'm leery of doing anything to 20+ year old heat soaked harness. A wire could have broken internally and is mucking things up.

leadfoot4

iTrader: (1)

Maybe the pickup fell off your oil pump....

Robbie Wilson

Yeah I'm going to have to check that. My oil pan is leaking anyway. I may aswell get the pan gasket replaced and check the pickup tube while I am at it.

I'll check out the harness too. MIght be something funny going on there. I think I Might have a ticking noise coming from a lifter or injector too.

I suppose if an injector is clogged it would run lean-obviously I guess lol.

It idles rich as hell though. stock tune with full bolt ons and I can see exhuast fumes just pour out of the pipes late at night.


So a update. THe sound might have been coming from the drivetrain. IT sounds like it could be near the belhousing/flexplate and I wonder if any of that stuff could have warped when the engine got super hot. I think maybe the flexplate cover got warped and sometimes touches making a "scuffing sound". When I put it in first and load the drivetrain just before the tires break loose I hear a "thunk dunk thunk" sound then the tires break loose and the sound goes away. If I Just spin the tires right away no sound so Its clearly something with the flexplate/tourqe converter. IDK. I May have gotton really lucky and engine could be fine.

leadfoot4

iTrader: (1)

I've heard of flexplates cracking....

Fazz73jr

iTrader: (3)

Thrust bearings maybe on there way out letting the crank walk back and forth in the block.

I got a spare motor with my car that had this issue:

Robbie Wilson

Thanks, I would have never thought of that. I still need to check things but now that I am thinking about it some more I don't hear the "scuffing noise anymore... ever" and oil pressure is seemingly normal/healthy.

That clanking sound is consistant when loading the tourque converter but I am starting to think it could be my pacesertter longtubes and ory hitting the bottom of the car. idk as silly as it sounds I know when I rev it up it sometimes hits the chassis. maybe loading the drivetrain causes the engine to move around more than free reving in nuetral and would cause the headers to bump the floor.

IDK though. I am worried that one day its all just going to grenade on me driving to school. I almost just want to go to the drag strip just to get it over with so I know what I Need to fix.

Is there an easy way to check the play of that bearing/crank with the engine still in the car?