Big2Bird

Your kidding, right?

71VetteLover

I have seen many You Tube videos in which guys ran their old clunker engines with no oil in them for 15 to 20 minutes at 2500 rpm before they finally seized. When you did the dyno pulls did the dyno technician verify it had oil pressure? Assembly lube alone would prevent the bearings from burning because dyno pulls only last a few seconds. Your main bearing shows signs of being overheated so I suggest you pull the #7 and #8 rod caps and look at those bearings. How about taking a couple of pictures of the oil pump drive shaft so we can see if they show any damage?

BB72

I hardly think I would get 10 pulls on the dyno going to 6000 rpm with no oil pressure and using hydraulic roller lifters without something grenading. As far as a balance issue, new balancer, new balanced bottom end a billet flywheel.

71VetteLover

As the seal end of the #5 main bearing appears to have been burned from running out of lubrication I would think the other four main bearings would be burned just as bad. And because of their 6000+ rpm reciprocating loading I would think the rod bearings would be destroyed. If the engine actually saw 10 full throttle dyno pulls with no oil pressure there would almost certainly be piston skirt and cylinder wall scuffing. Did you install a "heavy duty" oil pump drive shaft with the steel sleeve or an OEM drive shaft with the nylon sleeve? The reason I'm asking is the warranty on new oil pumps will be voided if the heavy duty drive shaft isn't used.

7T1vette

How would any sane dyno technician ever make ONE pull with ZERO oil pressure????

BB72

You will not reach 6000rpms with no oil pressure, lifters won't pump up.

71VetteLover

Mistakes CAN happen.

427Hotrod

Did we make a final determination? Is it back together?

JIM

71VetteLover

Hydraulic roller lifters have a .100" plunger travel so a dry lifter would subtract .100" of push rod lift. Assuming your cam would normally produce a .625" valve lift with 1.72 rocker arms and wet lifters the valves would only lift .453" with dry lifters. More than enough lift to reach 6000 rpm and with the grossly retarded valve timing it would favor high rpm. I highly recommend you tear your short block completely apart to see how much more damage it got from running 10 dyno pulls with zero oil pressure.

A dyno technician should verify it had full oil pressure before running a dyno pull but not all dyno technicians are GOOD dyno technicians.

BB72

The pic of the bearing appears dark but is in fact clean and shiny. The dark spot on the bottom is excess oil sitting because of the way the cap is positioned. I know for sure I have a steel sleeve on the shaft. I worked 12hr nights all weekend and just got up, I'll have more updates later today.

427Hotrod

I'm sure it didn't survive 10 dyno pulls with no oil pressure either. It had oil pressure or it would be a seized up lump by now.

The new oil filter idea seems most plausible at this point.

It's pretty easy to stick a wire through the cap oil feed hole on down to the filter pad if it's still apart just to verify...but you'd see a whole lot of damage if it was blocked.


JIM

BB72

I will double check things to verify before I reassemble it. I'll take a better picture of the bearing in the sunlight.

71VetteLover

How about a couple of pictures of the oil pump drive shaft?

BB72

Shaft is there, the good one.

TimAT

Safe bet that after that many dyno pulls there would be a big bunch of expensive blue color metal if there was no oil pressure.

'75

Seems like a simple phone call to the dyno shop would have solved the mystery awhile back. Filter was changed after the dyno session and not started again=empty filter and no engine damage.

427Hotrod

It did have some scuffing/metal transfer going on and some trash. Not " black death" type damage...but not perfect either.


JIM

lionelhutz

Those bearings may not look quite perfect, but they sure as hell don't look like they did 10 dyno pulls without any oil pressure.

71VetteLover

You misunderstood what I was asking for. I want to see pictures of the OIL PUMP drive shaft; not the crankshaft. The shaft that connects the bottom of the distributor shaft to the top of the oil pump shaft and is about 1/2" diameter and 6" long. The shaft that uses either a nylon coupling or a steel sleeve to ensure alignment with the oil pump shaft.

The #4 main bearing is burned a lot worse than the #5 main bearing because it's a lot narrower so I suggest pulling the other three main bearing caps to see how bad those bearings are burned. But as the connecting rod bearings see a reciprocating loading they need to be checked more than anything and I'll bet they are destroyed from operating at 6000 rpm with zero oil pressure.

427Hotrod

He already said the shaft with metal sleeve was installed properly.

JIM