Water pump housing thickness observation

[Durandal25]

Team,

well, in the process of rebuilding the Coronet 440 and ran into a real issue. I bought a water pump housing, cast # 2780987 - 7 and compared it to the one off my 383 unit, 2780987, just to find out that it's an 8th in thicker? I thought all units with the same casting number were essentially the same? Major fitment problem with my pulleys ect........

 

[Cranky]

Machining tolerances back then were pretty loose. I had a brand new piece of OEM trim that would fit one car but not the one it was bought for and neither car had ever been wrecked. It was 1/4" different between cars.

 

[Durandal25]

Machining tolerances back then were pretty loose. I had a brand new piece of OEM trim that would fit one car but not the one it was bought for and neither car had ever been wrecked. It was 1/4" different between cars.

Cranky,

I also have to belt-tension spacers that are different thicknesses as well and the between these two parts, one can make the correct fit, but I'll guarantee you that the -7 unit was mass produced this way with the shorter 1851608 spacer vs the 2806165 unit that came off the 383? Is this a 440 vs 383 thing?

 

[Durandal25]

...ok, so here's an interesting update. The difference is A/C vs non-A/C. The extra gap is related to the A/C bracket, I'v enever really compared these two before, but the fitment is exact. 2780987 - 7 is a non AC pump housing.

 

[5.7 hemi]

A/C non A/C are different animals!!

 

[Durandal25]

A/C non A/C are different animals!!

...yeah, and I'm a jackass for not figuring that out before I restored both parts, but I have a really nice non-A/C pump housing now.....

 

[YY1]

do the pumps have the same number of vanes?

 

[5.7 hemi]

I think the pumps are different count also.....but don't quote me!

 

[Durandal25]

do the pumps have the same number of vanes?

Yes sir, exactly the same except thickness.

 

[YY1]

Hmm. I thought they had fewer vanes for higher capacity.

Interesting observation.

It's always "fun" (meaning HELL) if you have to find brackets and pulleys for an engine that doesn't have the correct ones.

That's one more thing to consider.

 

[Meep-Meep]

I thought the dash number at the end of the P/N was to state how many times the casting core was used.

Interesting thread. I had no idea there would be a difference but it makes sense thinking about the brackets. Cool you figured it out.

 

[Durandal25]

I thought the dash number at the end of the P/N was to state how many times the casting core was used.

Interesting thread. I had no idea there would be a difference but it makes sense thinking about the brackets. Cool you figured it out.

....roger that sir, and it's a real deal. A/C equipped cars used a thinner pump casting due to the brackets. There are some different casting symbols on the unit that came off my 67, but no other indicators......

 

[Cranky]

Learn something new all the time! I thought there was a difference in brackets but not water pump thicknesses. Been a long time since I tore down an RB (20 years?) but have torn down a few B's in the past few years.....

 

[moparmarks]

Housings have same casting number but different part numbers.

 

[Gpuller]

Learn something new everyday. Always thought that the pump housings were the same, just difference in left or right inlet.