Oil Pump Fun

[Bob Riding]

After reading recent threads re oil pump failures @Marcel Backsand reconditioning procedures @JBNeal -thanks guys!, I've been getting into my oil pumps to see what's what. I have 3 pumps. Here's what I found:

1. (P28 Running) M37 (Melling) from a P28 running motor with decent oil pressure
2. (P28 Not Running) Chrysler branded pump from a P28 (not running)- stamped 1314611-99 
3. (C54 New 2003) NOS M37 from a 25" Chrysler 265 - installed in 2003, never run.

 

• All pumps looked OK. The M37 Melling pumps had some staining and the rotors were a bronze color and both had the upper shaft oiling hole

 

 

 

 

• The Chrysler pump, no oiling hole, but instead what looks like a brass plug

• The teeth on the drive gears had slight wear marks, but no missing teeth

• All measurements, that I could do, were within The Freewheeling Tony Smith's tolerances.

 

I used 320 and 400 grit sandpaper on a sheet of window glass to clean up the end covers and housings, then filled the up the cavities with Lubriplate #105 Motor Assembly Grease. Thanks @keithb7

They all operate smoothly, and I assume, will give me minimal trouble. 

A couple of questions:

1. FW Tony Smith cc'd the older Sealed Power (cloverleaf style) vs. the newer M37 (cross-style) and  found that the NOS pump with the cloverleaf style rotors is a high volume pump, moving about 10% greater volume per rotation than the newer style pumps.   I planned to use #3 pump in my 265, but if it pumps slightly less that the other 2 used pumps, is that a good idea since it is a slightly larger motor than the P28 230cid motors?
2. How do I remove the brass plug from the Chrysler pump? Grind down and drift punch it or drill it out?                                                                 

 

 

Edited December 7, 2022 by Bob Riding

[JBNeal]

That brass plug is probably a peened over pin...your presumption to grind off the button head and drive the pin out sounds correct to me.

 

I had wondered where Smith got his numbers for checking critical dimensions... eventually found the same measurements and verification procedure in the '48 B-series shop manual.  

[Bob Riding]

Thanks. I wonder why they would plug up the hole?

[Merle Coggins]

20 hours ago, Bob Riding said:

Thanks. I wonder why they would plug up the hole?

 

At first I didn't understand what you meant by, "both had the upper shaft oiling hole". Now I believe I understand your comment. That "hole" is actually the pin that retains the gear to the shaft. One of them looks like a solid pin that is peened over on the ends. Another one appears to have a roll pin. 

[Sniper]

57 minutes ago, Merle Coggins said:

 

At first I didn't understand what you meant by, "both had the upper shaft oiling hole". Now I believe I understand your comment. That "hole" is actually the pin that retains the gear to the shaft. One of them looks like a solid pin that is peened over on the ends. Another one appears to have a roll pin. 

 

And none of them is an oiling hole, that is in the body of the casting.

[Bob Riding]

So don't remove it!

[Bob Riding]

I just checked and none of them have the oiling hole. Thoughts on drilling them?

 

2 of the 3 were already working, apparently just fine.

[Dodgeb4ya]

There is no oiling hole on these pumps.

Those drive gears are retained by either a roll pin or a solid pin.

That's it.

Those gears are also pressed on. Don't attempt ro remove them unless you have the proper tooling to remove the gear...chipset teeth are the result of improper removal.

[Marcel Backs]

Given that the pump seizures occur in the shaft area, in my honest opinion the oil hole on the top of the shaft is essential. This seems to be a weak spot in the design. My NOS Chryco oil pump has the oil hole with a very pronounced countersink in it allowing the most oil to funnel in reaching the shaft. This pump has a heavier shaft housing which is not stepped like the contemporary replacement which have the oil hole countersink drilled in the middle of the step letting some of the oil to get by the oiling hole and less effectively reaching the shaft, These are some personal observations that resulted from my own oil pump crisis and luckily drove me to the NOS suppliers. M

[Bob Riding]

39 minutes ago, Marcel Backs said:

Given that the pump seizures occur in the shaft area, in my honest opinion the oil hole on the top of the shaft is essential. This seems to be a weak spot in the design. My NOS Chryco oil pump has the oil hole with a very pronounced countersink in it allowing the most oil to funnel in reaching the shaft. This pump has a heavier shaft housing which is not stepped like the contemporary replacement which have the oil hole countersink drilled in the middle of the step letting some of the oil to get by the oiling hole and less effectively reaching the shaft, These are some personal observations that resulted from my own oil pump crisis and luckily drove me to the NOS suppliers. M

Interesting. Do you have a picture of your pump?

[Marcel Backs]

here are some pix comparing the Chryco part with the Brand X. Chryco and BX have paddle type impellers as opposed to the cloverleaf style. Chryco gear is riveted and BX has a roll pin. Images 2 & 3 show the different shaft castings and countersink on oil hole. NOS part clearly has a better design. M

[Dodgeb4ya]

Oh oh....I see a oiling hole!?

 

[Bob Riding]

I'm assuming I can drill my pumps- the shafts aren't hardened beyond easy drilling?

[Merle Coggins]

11 hours ago, Dodgeb4ya said:

Oh oh....I see a oiling hole!?

 

Yup… I see them too. ?

[Sniper]

10 hours ago, Bob Riding said:

I'm assuming I can drill my pumps- the shafts aren't hardened beyond easy drilling?

 

Why would you need to drill the shaft?

[Dodgeb4ya]

I have never seen a factory flathead oil pump with a drilled oiling hole.

I just looked at a bunch of cores too...none have an oiling hole.

Odd to see one...not sure to any advantage unless roundy round racing.?

[Bob Riding]

2 hours ago, Sniper said:

 

Why would you need to drill the shaft?

Sorry, I meant the housing...

 

[Sniper]

I think the housing is just cast iron

[Marcel Backs]

The NOS one with the most prominent oiling hole was still in the wrapping paper and in the original box, therefore the oil hole was factory pierced and countersunk. It is quite obvious that the NOS piece is a better design than the mass cranked out "replacement". M