Oil pump questions

[hotcoupe]

Hello, I have a '39-'41 221c.i. bored to 239. The engine just turned 10,000 on the clock (I assembled the motor). I'm planning to replace the rod bearings (full floaters) and the oil pump, my question is can I use a Melling M-15 pump without any adverse effects? The reason I want to do this is because the engine on start up after sitting for a week or two makes a slight knocking noise. I did not use a new pump when the engine was assembled.
Thanx,
Tom

[Kube]

Originally Posted by hotcoupe

Hello, I have a '39-'41 221c.i. bored to 239. The engine just turned 10,000 on the clock (I assembled the motor). I'm planning to replace the rod bearings (full floaters) and the oil pump, my question is can I use a Melling M-15 pump without any adverse effects? The reason I want to do this is because the engine on start up after sitting for a week or two makes a slight knocking noise. I did not use a new pump when the engine was assembled.
Thanx,
Tom

I'd be much more concerned about that slight knock than what type of oil pump to incorporate.
That knock is not going to get better regardless of the pump chosen.
When you replace the bearings, I assume you are having the crank (at minimum) polished. Be certain to check clearances carefully at that stage of reassembly.
A stock pump is more than adequate for a stock build. More pressure is not necessarily an improvement.

[JSeery]

There are a lot of folks that prefer the original pump (even used) over a new pump. What is your oil pressure reading?

[hotcoupe]

The oil pressure is another issue, on start up the oil pressure is 50+, after running at high speed on the highway the oil pressure is 5 to 8 lbs.(at idle) At speed the oil pressure is 15 to 20 on a hot day.
Tom

[JSeery]

Originally Posted by hotcoupe

The oil pressure is another issue, on start up the oil pressure is 50+, after running at high speed on the highway the oil pressure is 5 to 8 lbs.(at idle) At speed the oil pressure is 15 to 20 on a hot day.
Tom

Does sound like a bearing clearance issue.

[JM 35 Sedan]

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The M15 oil pump is mainly used in racing engines that are built with more bearing clearances as compared to an engine built for street use. If you go with a new pump I would suggest using an M19.

[B-O-B]

I would think your oil pressures are OK. Make sure your gauges are accurate. I just completely rebuilt my 47 flathead & did not have a stock pump on hand & used a melling19 pump. Oil pressures are a bit higher than I would like but they may come down after it gets a few miles on it.
AS stated above I would be more concerned about the knock.

[Ken/Alabama]

I would use a stock pump especially on the engines that use the slinger in the rear instead of the rope seal. A higher volume pump will have a tendency to flood the rear main and cause an oil leak in engines using a slinger. One thing I always do when rebuilding one is to have the crankshaft ground to the next undersize and tell my machinist to leave the rear main "full" or on the high side of the measurement . By doing this it eliminates any oil getting pushed out the rear. An old Ford mechanic taught me that 30 years ago and he was 87 then. I still live by it . It works.

[Brian]

Would the slight knocking noise be perhaps a bit of piston slap?

[hotcoupe]

Thanx for the responses, I'm planning to remove the engine, find the problem and fix it - what ever it takes. And I think i'll use an original pump, does anyone know the end clearances (gears/end plate).
Tom

[Talkwrench]

Originally Posted by hotcoupe

The oil pressure is another issue, on start up the oil pressure is 50+, after running at high speed on the highway the oil pressure is 5 to 8 lbs.(at idle) At speed the oil pressure is 15 to 20 on a hot day.
Tom

Its sounds just like my engine and why I decided to build another. I had no problem with that oil pressure over the years for daily to and from work, however high speed running on the freeway never made me feel comfortable I did consider 'cheating' and using a high volume pump..

[oldford2]

Originally Posted by hotcoupe

Hello, I have a '39-'41 221c.i. bored to 239. The engine just turned 10,000 on the clock (I assembled the motor). I'm planning to replace the rod bearings (full floaters) and the oil pump, my question is can I use a Melling M-15 pump without any adverse effects? The reason I want to do this is because the engine on start up after sitting for a week or two makes a slight knocking noise. I did not use a new pump when the engine was assembled.
Thanx,
Tom

If the "slight knock" goes away when the engine warms up, my vote goes to piston slap. Floaters are great and if fit properly last 50,000 or more miles. So, why are you replacing them? I don't think your knock is rod bearings. Were new pistons installed at your rebuild?

John

[hotcoupe]

John, I guess my description of the engine starting events was incomplete. When I first start the engine there is a slight light knock, maybe two or three knocks and then the engine has normal operational sounds. That leads me to believe that a rod bearing is making noise until oil pressure reaches that rod journal.
Tom

[Kurt in NJ]

to find the "leak"---loose bearing you need a pressure pot to fill the oil gallerys, any bearing that has more than a drip is loose ---this way you know all the losses to your oil pressure

[hotcoupe]

Kurt, and everyone else who has responded with info and suggestions, thank you. I have resigned myself that the engine is going to come out and be disassembled. I'm thinking about using a "59" crank and "8ba" rods with insert bearings. Any pros and cons.
Tom

[42merc]

hotcoupe--A 59a crank & 8ba rods is not a good combo.
The 59a crank has a single oil hole per rod journal, for full floating bearings. 8ba rods require 2 oil holes per journal for correct oiling with the insert bearings.
Use an 8ba crank with the 8ba rods.

[hotcoupe]

42 Merc, I mis identified the crank as a "59". This crank has two oil holes on the rod journal. Would you recommend an insert motor over a full floater?
Tom

[Ken/Alabama]

Full floater gets my vote.

[42merc]

hotcoupe--Insert bearings are so much more user friendly plus they are more available & less expensive.

The oil holes on your crank, are they side by side, about an inch apart ?

[hotcoupe]

42 Merc, yes the holes in the rod journal are side by side approx. one inch apart.
Tom