I'm trying to determine if Y-block cars that came from the factory with air conditioning also came with smaller-diameter water pump pulleys than did Y-block cars that were not equipped with a/c.  A friend tells me that all GM vehicles of the same era that came with factory-installed a/c units had smaller-diameter pulleys installed that did cars without a/c.  The purpose, of course, was to increase the RPMs of the water pump and the fan to protect against over-heating at idle when the a/c is turned on.  If Ford did, in fact, install different size pulleys in their a/c-equipped cars, it would be very helpful to know the diameter of the different pulleys used by the factory for both a/c and non-a/c cars.  I'm researching this because I recently installed after-market a/c in my '56 312 c.i. Fairlane that came from the factory without a/c, and while it works well, the engine does heat up quickly on a hot day in slow-moving or stopped traffic.  A fix I'm considering is going to a slightly smaller-diameter water pump pulley and it would be helpful to know the best diameter pulley to use.  Thanks, Ron

Ted Eaton replyed here on an overheating thread that Ford did indeed use different pulleys in various parts of the country but did not mention A/C as I remember.
A test for you is to start the engine cold and let it warm up with the cap off and the tank about 1 to 1-1/2" low. If after it has warmed up to operating temp and you see no movement of water by looking in the tank; then just barely raise the idle and if you see movement install a smaller pulley.
My 56 ran hot at signals at idle and drove me nuts. I did the test above and there was no water movement. I bought a pulley and spacer kit from Summit for a 302 67-68 Mustang. It was chrome and I painted it satin black and my cooling problem went away. It was a little over 5" and mine was over 7". I also put a pipe plug in the bypass with a 1/8" hole drilled in the plug. I too will be adding A/C soon. Good luck.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

The smaller pulley is a pretty common fix, as is the bypass restrictor and the elimination of the w/p spacer on the bird's and spacing the pulley out to line up. Most aftermarket a/c kits come with an electric pusher fan for the unit out in front of the radiator. Got one of those? They normally aren't big enough to provide any engine/radiator cooling.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I have an electric puller fan that does the job until I hit slow traffic on a hot day.  My stock water pump pulley is 7" in diameter as measured from the lips (not from the bottom of the groove) and I think I will install the 6" diameter pulley I have and see if that takes care of the over heating problem at idle.  In the back of my mind, though, is whether this smaller diameter pulley is going to cause me problems at freeway speeds on long trips because of the increased pressure caused by the higher RPMs.  Any thoughts on that?  Thanks, Ron

Short answer, no. At least no one else has reported a problem. The water pump never moves enough water to be restricted by even the thermostat. If in doubt, fit one of the high flow stats for a mopar. Robert Shaw, can't remember the # right now. Others here will.

Greenbird56 has posted a great description of fitting a Hayden clutch and modified fan. He's in Tucson, and 110 degrees happens in the summer. Might do a search if you need to. The most important thing is a good shroud on whatever fan you use on the puller/radiator side.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Water pump RPM should be kept below 7000rpm.  On a typical street engine, it will never exceed that rpm with even the smallest diameter pulley that can fit and it certainly will not happen at freeway speeds.


Lawrenceville, GA

My factory 3 belt ac water pump pulley measures 6 3/4" (1956 312 built in Texas) outside dimensions. I replaced it with an FE big block it measures 5 ".bolted right up. Had a heck of a time getting belts to work. Later discovered that flow kooler makes a high volume wp for the Y. 12 vanes vs 8. $170.00 spent that much on belts and the pulley.

Duane

Not only is the stock water pump flow pretty low at idle - but more so when in gear with an auto trans. Have a trusted soul sit at the wheel when you try this.....
Water movement in my 'bird radiator (as seen through the radiator cap opening) was just about nil. In neutral, I revved the engine until the disturbance looked closer to what I used to see in my old '67 Cougar. It cooled just fine and I don't believe the waterpump was over-revved even at full throttle. The increased RPM level was a hint at how much smaller I was going to have to go to get the desired results.

 
 Steve Metzger       Tucson, Arizona

I see that CASCO has a "High Output" water pump that I spotted on page 29 of their 2016 catalog, part #8501HO.  The price is set at $149 and includes a new gasket.  Of interest, they also say they will modify owners' stock water pump for increased output for $50 (part #8501HOY).  Seems that something like this along with a 5" or 6" down-sized pulley would bring the temp down to reasonable levels on hot days at idle with the a/c blowing.  Has anyone installed one of these HO water pumps?  Ron...

The casco pump is for T-Birds, which have a 1" water pump spacer (which is a big part of their cooling problems) so it will not fit your Fairlane.  The stock pump works perfectly fine as long as it is in good condition.  Check coolant flow at idle, as already mentioned, and adjust as necessary.


Lawrenceville, GA