Mellings M15 Hi Volume Pump
 

I have a new USA made (marked 1999) Mellings M15 high volume oil pump which I just acquired in a batch of parts.

I've read & heard pros and cons. What's your opinion, should I keep it? Mostly I will run street engines though may build a big bore stroker someday.

Thanks Paul J.

Re: Mellings M15 Hi Volume Pump
 

Ditch it.

Re: Mellings M15 Hi Volume Pump
 

The only thing that pump is good is a worn out engine or a full race engine with extra bearing clearance. Walt

Re: Mellings M15 Hi Volume Pump
 

We don't even use them in race engines any more.

Re: Mellings M15 Hi Volume Pump
 

I'm installing one in my V12. I think it would be overkill in a V 8. And it might be in my V12 also,we shall see.

Re: Mellings M15 Hi Volume Pump
 

I have one in an 8ba, everything is tight,less than 1000miles, but it has very low oil pressure at idle. I'm running 20w50 Brad Penn oil, I checked for the restrictor in the oil filter line, I even plugged it no change. Cold at road speed it carries almost 60 lbs, after it warms it drops to 45-50 at speed, but idle is 5lbs or less. Could it be something with the pump? Motor is quiet, I have two gauges on it, one electric, one mechanical, they both tell the same story. The only answer I guess is don't slow down!! Chuck S.

Re: Mellings M15 Hi Volume Pump
 

Chuck , do you still have the "Mechanical Fuel Pump " PUSHROD in your engine ? The stock spring in the front of the block ?
j

Re: Mellings M15 Hi Volume Pump
 

In your case the M-15 pump is probably saving the engine, if you had a regular M-9 pump you probably would have pretty low pressure, I think you'll find you have a lot of clearance somewhere in your engine. Walt

Re: Mellings M15 Hi Volume Pump
 

Walt, what is the M9 pump?

I know about the M15, but not the M9.

Harry

Re: Mellings M15 Hi Volume Pump
 

I am thinking Walt meant M19.

Re: Mellings M15 Hi Volume Pump
 

Yea, M-19, I'm on my first cup of coffee. Walt

Re: Mellings M15 Hi Volume Pump
 

Would the M15 be worth using in a Ardun?

Re: Mellings M15 Hi Volume Pump
 

No.

Re: Mellings M15 Hi Volume Pump
 

Engine is an 8ba so the relief for oil pressure is in the pump. And I do have the fuel pump push rod & the fuel pump, I'm baffeled.

Re: Mellings M15 Hi Volume Pump
 

Thanks Walt, I guess the right way to find out what is going on, is.... Pull the oil pan, and hook up a 4-5qt oil reserve, and see first hand where the hemorrhage is.Gee it's gone over 800 miles can't be too serious, thanks Chuck S

Re: Mellings M15 Hi Volume Pump
 

While on the subject of Mellings pumps. I haven't used them for the past 15 years at least due to the fact that their junk in my opinion. I've had to replace several of them. I now use stock 49/53 ford pumps. Just clean them check the cover and housing for ware and re assemble I have a fixture that tests them. There are several other people here that will check out your pumps as well.

Re: Mellings M15 Hi Volume Pump
 

Basically the M15 is a good pump. The manufacturing tolerances are the problem. I always took a new pump apart and checked everything. Sometimes, (more often than not) a few things needed tweeking.
I would still use one in a customer engine if the racing rules said, no dry sumps.

Re: Mellings M15 Hi Volume Pump
 

I have never seen any big change in oil delivery when switching between a stock, helical gear, pump and the M-15 pump. In the "good old days" I made several "double pumps" for loose clearance engines. These consisted of 2 stock pump gear sets combined in one case. Had to cut a hole in the oil pan and weld a voltage regulator cover to the bottom of the pan to fit those things in there. Again, not a huge change in output. It all has to go through the stock screen, housing, tube, and inlet opening.

There are several places to look for leakage when apparently tight engines show low oil pressure. The fitment of the pump housing to the engine block, the center oil manifold tube, and the bypass valve seat are some of the more difficult to diagnose which I have found to be troublesome areas.

Re: Mellings M15 Hi Volume Pump
 

JWL, Thank you for your Ideas on internal oil leaks. I'm real sure the bearings are tight and anything that could be related to a fresh rebuild SHOULD be ok.I didn't check the pump real close, it could be something with the by-pass or fitment inside the pump. I had an 8ba that the oil gallory plug never got put back in, this seems different from that in that it can build almost 60lbs at road speed when cool. This engine is totally quiet when idling with low or no oil pressure. Winter is almost here, we will have lots of time to check it out, thanks again, Chuck S.

Re: Mellings M15 Hi Volume Pump
 

I would get another gauge and confirm all my findings,and troubleshoot from there.

R.