wasted another engine

[Dave]

I will try to make this short.
Oil pressure 20 idle, 60 WOT on all engines before problem starts.

First rebuild lasted 4000 miles, main bearings went out, rebuilder
did not know why.

Second rebuild lasted 500 miles, disassembled myself and found nothing, took block and main caps ext. to a diferent rebuilder to have it checked out, everything was fine.

I decided to go with a completly different engine, bought a low mileage long block that was in excellent condition ( inspected by a rebuilder and myself) It lasted 300 MILES!. mains again!

It is ok until I make a WOT blast into 3rd gear then oil pressure starts dropping , then the knock ( mains) follow shortly after.

Inspected new timing cover (GM) that has been on all the engines and found the outlet side (inside the pump gear housing, the tapered hole along side the pump gears- towards the front of the engine) is smaller in diameter than other good timing covers- about 30 thousands.
Need opinoins.
Going nuts.

DW

 

[Chuck Leeper]

Mains gone south??

Dave, the mains get oil BEFORE the rods and you say the rods are ok??
Is the thrust face on the main gone??
How much end play was there on the crank when you put it in??

Sounds to me as tho the converter is a possible problem... Is it the same converter each time??? Whose converter? Did you check it to see if it was balooned?
Did you check crank end play after yo put the engine/trans together??
I doubt the ft cover at .030 less than others is the culprit. Something is overloading the crank...

 

[Joe 1320]

I second the converter theory. I've seen a converter take out a crank just like what you describe.

 

[bruce]

Got any pics of the bearings, plugs?.

Were you monitoring oil temp?.

You can tune a lean/too much timing situation where you're not in detonation, but putting tons of heat into the bearings.
What HP level ya at?.

How did you determine, the various bearing clearances were correct?.

 

[Dave]

On the first rebuild I did not see the bearings but the builder told me the #3 was wiped out and no mention of the thrust.

On the second rebuild I disassembled it and found the # 3 was wiped out and the #2(thrust) was not as bad, however the sides of the thrust bearing were untouched and looked great. The rod bearings were showing signs of heat but not wiped out (scored).

The third engine is a low milage never been apart engine. The #2 and #3 mains were pulled for inspection and looked great. The crank was tapped with a block of wood in one direction with the thrust cap somewhat snug to line up the cap and thrust surfaces then torqued. I have not pulled the rod bearings yet. The thrust surface in scored on one side. the flywheel side, I believe. The bearings were analysed by a bearing manufacturer on the second rebuild and they claim a lubrication problem, keep in mind the thrust surfaces on the second rebuild looked great even though the other sufaces were wiped bad.

The convertor is a Precision that was installed shortly after the first rebuild. Trans at the same time by Jimmy's.

Every one that has seen the bearings feel this is not happening suddenly, it's from the time I first get it running and when finally jump on it, it cant handle the increased load.

Boost at 16#
knock 1.4 on the shift
O2's @ 804

Cas front mount
009's
PTE 52
had a 212 cam in the first and second rebuild
stock cam in the low milage engine
THDP
fuel pump
chip @ 20 degrees

 

[Intercooler]

Did you have any debris from a previous meltdown in the oil cooler? What did the filter look like when you cut it open?

 

[REDS HOT AIR]

everyone musta missed the part about the oil pressure falling in high gear...if its falling in high gear your sucking air ..either your running it low on oil , have the wrong pan on it, or you just need to run it over full so the pickup dont get uncovered.

if your running a high volume oil pump toss it and go back to normal and leave the extra oil in the bottom of the motor for high gear

 

[Chuck Leeper]

Suckin what??

Red, you been hangin w/ Jason too long!! J/K.. High gear is where the acceleration takes a dump.. If it were going south in lo or 2nd, then I'd be thinking outrunning the oil supply...
Nothing so far explains why the mains are going first.... A loss of oil supply would get the rods first, then as the supply deteriorates further, the mains go....
Wrong oil pan? Was the same pan on all 3 engines?? Was the pickup put on without the gasket??

This cover was not ported by a "well known vendor" that is now out of business was it?? I got "laid" by this A/H and was told I didn't know what I was talking about.. 2 engines later....Got the price of the cover back and a comment that "the cover is on my personal GN and has no problem whatsoever". I guess that's why he's no longer a vendor... The arm in a cast probably saved him a goodly sized dental bill....

 

[Dave]

I did not cut the filter open , just poured the oil out and could see the bearing material flowing like a seperate liquid in the oil.

I flushed and flushed and flushed the cooler everytime.

Gasket has always been installed on the pickup tube.

Same pan on all engines, it's the one that was on the original engine when I pulled it to rebuild the first time.

Same balancer and flywheel, cam sensor and timing cover -not ported

DW

 

[motorhead]

Damn... this is rough

Good luck

 

[Steve Wood]

As is repeatedly posted here, one cannot flush the oil cooler. It must be replaced. That may, or may not, have anything to do with your failures. It certainly ups the odds of metal contamination, tho.

 

[REDS HOT AIR]

Originally posted by Dave
IIt is ok until I make a WOT blast into 3rd gear then oil pressure starts dropping , then the knock ( mains) follow shortly after.

so nobody has ever pumped a pan dry in high gear...or do you just not know??

 

[Nick Micale]

My comment would be do not use that cover/pump on another engine. No other reason for oil pressure falling and bearings going away unless the machinist did a lousy job.

The stock pump/cover for a turbo motor is an excellent piece. They best were hand-selected from the test stand at the factory.
I have NEVER had a bad one.

The problem motors brought to me that others had done almost always had an aftermarket cover. Some were the result of poor build, but always low pressure went along. Have known of a couple cams [gears] destroyed by HV pump and new cover.

Some of the aftermarket covers have done fine, but I still prefer to do mods on the factory one. Just an opinion, Chuck already mentioned his EXPENSIVE cover problem!

 

[Dave]

Is it safe to run without the oil cooler?

DW

 

[FJM568]

Sure is...The 84/5s came without the oil cooler...The oil cooler was added in 86...

Just pull the oil cooler adapter off...The part between the oil filter and the pump cover and cap the cooler ports on the radiator...

 

[Steve Wood]

Don't ignore what Nick suggested. The cover/pump and cooler are the common denominator in the situation.

From many posts here, it would seem that many don't understand that these pumps have to be installed with the proper clearances, etc. The pump gears and cover may be scored and/or badly worn.

I think the aftermarket high volume covers are "iffy" in consistency and agree with Nick about using factory units although all must be cleaned up and the tolerances examined.

As far as oil being pumped to the top of the engine and the pick up uncovered. Anything is possible but most of our engines don't turn the rpm/volume required for this to be a problem from what I have seen. I cannot recall the guy that participated in the Silver State run but I don't recall anything particularly trick in the oiling.

 

[Dave]

I will not use this GM cover anymore.

I will also set the clearance on the pump gears with the proper thickness gasket on the other GM cover I have and different gears.

I also wanted to eliminate the possiblity of the cooler, that is why I asked if it's was ok to run with out it.

DW

 

[ULYCYC]

When I wiped out my motor from the Budget Cam failure (leave it a dead story) cam and bearing material was everywhere. Make sure you do a "total" teardown and boil the block and make sure all parts are free of contaminates. Get a new oil cooler or leave it out of the loop. And don't forget to open up the turbo and flush it out. I was surprised what was in there. Before you start the engine make sure you get good oil pressure with a drill.

 

[Steve Wood]

It left me dead, but not a story...