Not All Oil Pump Drives the Same?

[dibbons]

I mistakenly purchased two oil pumps drive for a 340 I am currently rebuilding. After examining them side to side I found the gear end is slightly different. One has a gear teeth that measures about 16 mm (.630") high/thick (green paint splash in photo) and the other measures only 14.5 mm (.570") high/thick but does have a "step" machined in to make up the difference (photo right). Does anyone have a factory oil pump drive on hand to find which is factory correct? (probably won't make a difference but I am curious about the discrepancy). Thank you. (also posted on FBBO)

 

[ch1ll]

Both of those are direct connection or mopar performance drives. You can tell by the radius on the hex that drives the oil pump. Stock has a sharp corner and has been known to sear off under extreme conditions or from fatigue. Are both of the gears cast iron? One may be for roller cams if it is a different material than iron. If they are both iron they may be from different vendors Chrysler used.

 

[dibbons]

They both have a spray of yellow paint which does not show in the photo because of the orientation of one of the drives. The material of the two gears look to be the same to me.

 

[S'cuder]

Those are getting a little scarce. Don't be surprised if someone offers to buy one.

I'm not offering, so please don't delete my post!

 

[Kern Dog]

Uhhh, did you mention millimeters ?

This is America, man!

Just kidding, Ody. I think as long as the seat where the distributor shaft sits in is the same, it shouldn’t matter.

 

[Oldmanmopar]

Now that you mention it. Is any for sale?

 

[dibbons]

Nothing for sale at the moment.

 

[Bobzilla]

Melling IS-72 is currently available. It has a hardened tip with the radius and comes with the bushing. Not pinned, but if you really think it needs to be pinned just drill it and add a steel tension pin from your local hardware store.

Oil Pump Driveshaft source

 

[Bewy]

So are the gears plastic?

I wouldn't worry too much that a variation in the thickness of the gears. Contact is in the centre of the gear teeth, not the outside edges.

 

[RustyRatRod]

Just subtle differences from one manufacturer to another.