Hi,
We are having issues with an H2 engine rebuilt and more specifically the oil pump is wearing into the housing and causing a sound.
At first started out with a general maintenance when we found metal in the oil pump. Turns out the crankshaft bearing was damaged. So we installed new crankshaft bearings, connecting rod bearings, new timing set, new oil pump, new gaskets and seals. Fired it up, and it was running ok, but had some grinding noise. We let it go for about 500miles and a break-in and by the end of the 500miles it developed lifter noise. We tore it down and it spun crankshaft bearing, very noticeable wear inside oil pump housing and the cover plate, and also on the crankshaft timing sprocket from touching the oil pump. We took it to a machine shop, where it was rebuilt. New bottom end again, top end, everything was properly measured, cleaned, balanced, resurfaced. We installed a new oil pump (Melling this time and not GM), fired it up and had the same sounds right away, we were running it for about 2 hours. Tore it down again, same wear on the oil pump cover. So we ordered another oil pump, melling again, a new crankshaft timing sprocket. We installed it following the alignment/shimming method to center it with feelers, rotating the engine, oiling it before torquing the pump down. Again same problem, same sound, same wear on the oil pump cover plate after running it for about 30mins. At this point, we checked the gaps again inside the pump, and everything was good, the gaps did not disappear, the gears were moving freely.

We are running out of ideas. We do not think all 3 pumps would be defective. Because of the machine shop we do not think the crank or the block would be somewhat bent to cause such misalignment and wear. We are afraid to let this go, because of our first encounter.

Did anybody see similar oil pump wear after just 1-2 hours of running engine (vehicle was not moving)? Is this normal wear because the internals of the oil pump has some play?

Please see pictures attached. One is showing the marks on the sprocket where only 2 splines has that mark, where the oil pump housing may be touching earlier. Another picture of the inside of the oil pump housing. showing some wear. And finally the oil pump cover plate where the wear is noticeable.


wear on the inside

wear on the cover plate

wear on the cover plate

wear on the sprocket

 

you probably need to check the crankshaft end play and also check your crankshaft thrustwasher clearences.

 

Hi, Thank you for the idea. We have checked the crankshaft play and clearance. Everything is within normal values.
We checked with the machine shop as well. They are inspecting the pump, because they think it is the pump.
Can it be possible that 3 different pumps may have an issue? Pretty much the same issue, same wear on one side?

 

Torque convertor maybe?

 

What do you mean by the torque convertor? Should we disconnect it and try it that way? How may the torque convertor cause such wear on the pump?

 

if the torque converter is not seated fully into the transmission it will push the flywheel and crankshaft forward into the pump especially if your thrust washers are worn.
did the machine shop regrind your crank and not compensate the difference for endplay but tell you everything is fine?

 

I didn't read about priming the engine? "Oiling" the pump on assembly isn't enough. I remove the plug on the front, lower driver side of block. Get the adapter to screw in and convert to 1/8 NPT. Install 1/8 barb. Buy a cheap 2 gal weed sprayer, cut the wand off. Push hose on and pump about 5 qts oil in until it's coming out the pushrods. Remove barb, replace with 1/8 NPT plug....later you can add temp sensor, etc if wanted.

Starting the engine not primed will do just what you're experiencing.....

Manual says but something like 8 ounces in that part with funnel . No thanks, better to prime the entire engine, pre filling oil cooler, filter, etc ...

That's my .02 cents worth....and I did that last weekend:-). Instant oil pressure on first start

 

"We installed it following the alignment/shimming method to center it with feelers, rotating the engine, oiling it before torquing the pump down."

That's not priming it....