Hi there just put in a new rebuild engine 410 was driving to day and had the low oil light come on and soon the engine sounded like a deisel.what is the possible causes sounded good in the garage to start with

Derek, don't start that motor again. Assuming yours has had a professional and complete rebuilt, I would not even touch it without the rebuilder/shop owner present (warranty issues).

Your oil pump might be bad, the shaft that drives it might be bad, or one of the internal plugs in the oil galleys might have come loose.

A similar thing happened to me last year with my (more than completely) rebuilt MEL 462. After twenty minutes of engine break-in the oil pressure went down considerably. We shut it down and removed the spark plugs, fitted an external oil pressure gauge, and turned the engine using the starter. No pressure.

We dropped the oil pan to check out the (brand new) oil pump. It had gone bad. The plunger was stuck open & had to be forced back with a screw driver before it could move freely again. So the pump was pumping but a large part of the flow just went back straight into the pan (I hope I'm describing this right, KULTULZ).

So a new Melling oil pump & custom drive shaft were fitted. The drive shaft worked like a charm and for $20 it's a cheap piece of mind. Glad I had the foresight to have a replacement pump & shaft at hand. I'm also glad it was a bad pump because otherwise I would've had to pull the motor and bring it back to the rebuild shop. The old pump had a steel Melling label attached to it but I couldn't find any # on the pump itself proving it was a Melling pump. The new one from Lincoln Land did have the right part #.

Anyway, when cranking - not starting - the cold motor the gauge read just over 40 PSI. As you may remember we tried this with the first (and now known to be bad) pump. The needle literally barely moved then. We started the cold engine: PSI came up to 60 when revving it a bit. With the motor properly warmed up it was +40 PSI at 50 mph.

On that custom drive shaft, I replaced the original with this billet drive shaft from Precision Oil Pumps in Ca, (559)325-3553. The original is literally as thin as a pencil and really isn't up to the job. This replacement works for the MEL engines. It is an FE drive that is +.0375" Longer for Main Girdle Applications. This shaft is about .075 too long, but the MEL guys get them and grind that amount off the bottom (pump end) to make them fit. Just use a bench grinder. The shafts are $20.00 plus shipping.

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Might be a plug popped out of the oil galley. I don't know how much tech laps over to the MEL family from the FE family but years ago we had the exact same problem on an FE rebuild. A missing oil galley plug did the same thing on the FE family. We tried 3 or 4 new oil pumps before we discovered the problem. Rare but it does happen.

Rocky

well your right the shaft broke and the pumps stuck so i need a new pump and shaft i guess one with a vacume pump on the bottom is in never never land so what do i get at my local napa or whats the best replacement thanks derek

The MEL and FE pumps are the same. Not really sure with the vacuum pump. It is piggybacked onto the oil pump. The bottom plate (cover) to the oil pump (with vacuum pump) is unique so hold onto that.

Take your pump (remove vacuum pump) and compare it to a MELLINGS FE pump at the parts store. Use the larger pump drive (the combination pump drive is unique in length so be careful here).