72 Jeep 304 V8 oil pump gears

[A 71 CJ5]

anyone know what the dimples mean on my water pump impellers? do they have to line up or be on the same side? just want to make sure i put it together right

 

[shum8]

anyone know what the dimples mean on my water pump impellers? do they have to line up or be on the same side? just want to make sure i put it together right

Not only do I not know why the dimples are there, now I'm wondering if mine had dimples that i didn't notice when I installed 'em......Anxious to see what falls out of this tree....... Sighhhhhh.

 

[A 71 CJ5]

anyone know what the dimples mean on my oil pump impellers? do they have to line up or be on the same side? just want to make sure i put it together right

sorry- I meant to say-OIL pump impellers.

 

[jp360cj]

I don't know either, but interested to find out..(so hopefully someone on here does!)

 

[A 71 CJ5]

I could not wait any longer so I called Melling oil pumps and asked to speak with a tech- he says the dimples should be on the same side-in this case facing up. as to why the impellers were marked he really did not know-possibly a slight chamfer for installing the idler gear easier ???????
for those who may be worried now he also mentioned that it doesn't really matter as long as they're in there.
is this something a pro would know right off the bat? anyway- it is good enough for me-I want my rig back on the trail.. thanks JEEP C J .COM

 

[Tinman22]

Drilling dimples into the bottom gear face allows oil to well up in them providing lubrication for the lower plate reducing wear. Many aftermarket pumps have them. Not saying melling was wrong just a side note. Pretty common mod for 231 buick v6 's with alluminium front covers.

 

[A 71 CJ5]

thanks Tinman- I had seen the modified pumps in my search for oil pump impeller marks.
my impellers have just 1 mark each-almost like a timing mark. since it does not matter maybe I will run them opposite-a little extra oil on the cover to cut down wear could be good.

 

[Tinman22]

Bulltear has a nifty gear set for amc pumps. Bulltear.com