Water pump, A/C vs. Non A/C???

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ValiantOne

ValiantOne

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Hey All,

Engine is a 68, 273 w/ the older iron water pump.

The books call out a different part # for the a/c cars. Anyone know for sure what the actual difference is?

Thanks,

CE
 
the impeller is the difference, how much water it moves, how much load it puts on the engine.
 
6 vein = AC pump
8 vein = Non AC pump

AC water pump pulley = Smaller diameter
Non AC water pump pulley = Larger diameter
 
ValiantOne said:
That is what i thought but my a/c pump has 8 vanes. It is a rebuild though. Maybe they put the wrong impeller back in it?
Click to expand...

Not sure what happened with your pump, but for AC it has the wrong impeller. :)
 
Ha, the new (rebulit) w/p from napa has 8 vanes too. Supposed to be an a/c pump as well.

Good thing im not using the a/c right now......

Thanks all
 
brasil said:
Milodon highflow wp comes with 8vanes too

Greetings Juergen
Click to expand...
as said the AC app has a faster pulley ratio for more airflow but that higher ratio can make an 8 blader cavitate at higher RPM's so they dropped back to 6 blades & with the higher ratio 6 blades is enough to cool. You want the best of both worlds? get an 8 blade & weld on an anticav plate & now you have the most flow & no cav possibility. I cut a round plate out of the side of an old washing machine with the OD slightly less than the tips of the vanes so you can tack several vanes and drill a hole in the center to tack there also. to go further you can press the vanes closer to the case (.030" is ideal) & support the shaft on the other side where the cross is when doing this & put some feeler gauges under the vanes (.030") as it may "jump" when pressing then there's a big problem. then between the cav plate and the flat on the timing cover you want .030" also (keep gasket thickness in mind) & a thicker cav plate or bolt a flat piece on the flat (flat head bolts & "the right stuff" Permatex gasket maker which is the best
 
Okay, So now I've seen 3 A/C pumps and one non-A/C pump.

All three A/C pumps had 8 vane impellers and two outlets on top. The only other difference was that the back side (engine side) casting for the water passages was much deeper than the non A/C passages.

The Non-A/C pump had three outlets in the top surface, and the aforementioned shallower passage casting on the engine side.

Interesting.

CE
 
Rapid Robert said:
as said the AC app has a faster pulley ratio for more airflow but that higher ratio can make an 8 blader cavitate at higher RPM's so they dropped back to 6 blades & with the higher ratio 6 blades is enough to cool. You want the best of both worlds? get an 8 blade & weld on an anticav plate & now you have the most flow & no cav possibility. I cut a round plate out of the side of an old washing machine with the OD slightly less than the tips of the vanes so you can tack several vanes and drill a hole in the center to tack there also. to go further you can press the vanes closer to the case (.030" is ideal) & support the shaft on the other side where the cross is when doing this & put some feeler gauges under the vanes (.030") as it may "jump" when pressing then there's a big problem. then between the cav plate and the flat on the timing cover you want .030" also (keep gasket thickness in mind) & a thicker cav plate or bolt a flat piece on the flat (flat head bolts & "the right stuff" Permatex gasket maker which is the best
Click to expand...

would love to see pics of that mod. If I understand correct you are moving the pump away from the timing cover the thickness of the plate right? That will cause a bit of belt misalignment with the crank. Any problems there?

Best,

CE
 
ValiantOne said:
would love to see pics of that mod. If I understand correct you are moving the pump away from the timing cover the thickness of the plate right? That will cause a bit of belt misalignment with the crank. Any problems there?

Best,

CE
Click to expand...
No, there is a great distance between the impeller vanes and the flat of the t cover. You are reducing that to greatly reduce what the engineers call "parasitic recirculation" to make a vastly more efficient pump. the OD of the plate is slightly less than the OD "tips" of the vanes (so you can weld em) and yes the vanes/plate sticks out past the pump face perimeter where the gasket is but with the deep recess of the t cover flat there is still clearance between the cav plate flat and the t cover flat & the pump still fits on the t cover perimeter with the gasket like normal. dont have a pic but see how much distance there is between the vanes and the t cover flat & that big space is what you are wanting to reduce. On a side note, if the t cover is off look in the 1" port openings on each side & halfway in you will see a casting ridge made when the poured the alum into the mold & 3 minutes with a die grinder will remove it for a more unobstructed passage
 
ValiantOne said:
Okay, So now I've seen 3 A/C pumps and one non-A/C pump.

All three A/C pumps had 8 vane impellers and two outlets on top. The only other difference was that the back side (engine side) casting for the water passages was much deeper than the non A/C passages.

The Non-A/C pump had three outlets in the top surface, and the aforementioned shallower passage casting on the engine side.

Interesting.

CE
Click to expand...

All you have seen is parts marked incorrectly.
Not sure why you are making this out to be more than it is ?
 
Lol. I just looked in my FSM for 1967 Dodge Dart.

273, 2 bbl, 4 speed and auto trans w/ A/C: 4.20 diameter impeller w/ 10 blades
Same as above with Clean Air Package: 3.50 diameter impeller w/ 6 blades

I havent even seen a 10 bladed impeller yet.

Just measured the impeller on my 8 bladed A/C unit at 4.20. well it is the same as the original. Hope it all works out!
 
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ValiantOne said:
Okay, So now I've seen 3 A/C pumps and one non-A/C pump.

All three A/C pumps had 8 vane impellers and two outlets on top. The only other difference was that the back side (engine side) casting for the water passages was much deeper than the non A/C passages.

The Non-A/C pump had three outlets in the top surface, and the aforementioned shallower passage casting on the engine side.

Interesting.

CE
Click to expand...
are these pumps NOS? If they are parts store rebuilds you get what ever impeller they have to rebuild the pump. Lots of guys trying to get the ac pump have had to order from 3 or 4 different places to get the correct 6 blade impeller. I have 2 cast iron water pumps, both were on 68 340's non ac, 8 blade impeller 4.20 diameter.
 
gtsdude said:
are these pumps NOS? If they are parts store rebuilds you get what ever impeller they have to rebuild the pump. Lots of guys trying to get the ac pump have had to order from 3 or 4 different places to get the correct 6 blade impeller. I have 2 cast iron water pumps, both were on 68 340's non ac, 8 blade impeller 4.20 diameter.
Click to expand...
Agree. Thes have all been NAPA auto reman units. Seems like they use what they have. Ive never even seen the 10 blade impeller mentioned above.
 
Rapid Robert said:
the 10 blade is a typo/misprint
Click to expand...

That doesn't seem very likely as they show a picture of a 10 bladed impeller for th sb engine on page 7-6 of the fsm, and list it for not only the dart models but every Coronet model (excepting slant six) as well.

The interesting thing is that the 10 bladed impeller looks to be a cast unit with a flat across the back and a few holes running around the circumference of that plate verses the stamped steel impeller I have always seen.

Again interesting.
 
water pump.jpg


Like this one? but with 10 not 8 blades?
 
Me either, was on ebay few weeks ago, might still be, claimed to off a 64. That is the same premise as welding a plate to the impellor, which I still need to do on my 340.
 
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