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Re: strange cooling

Posted: Thu Jul 12, 2018 6:19 am
by bohica2xo
I never did much with Pontiacs, so I had to go pull up some pictures. Yep Underdrive fan & water pump. That water pump pulley is HUGE.

Same problem we have with early Mopar LA motors.
I know that mopar swapped pulley ratios on A/C cars. Non A/C unit were 0.95:1 and A/C cars were 1.56:1 You may find that Pontiac did the same thing. The good news is many water pump pulleys have the same pilot bore & bolt spacing.

You have a solid drive fan - is it the OEM unit or an aftermarket part? Is there room for a larger diameter fan?

Re: strange cooling

Posted: Thu Jul 12, 2018 8:11 am
by grumpy old man
Yep, when I was putting this thing together the size of that pulley never even entered my mind. Been away from the business for too long, or maybe not long enough depending on your point of view. I do know that this Indian will probably be my last car, I do not think that I have another build in me.

I contacted Franks Pontiac parts which is a Pontiac specialty salvage yard in Twenty nine palms. I gave them the measurements of what I need and they don't have anything close. Maybe today or tomorrow I can take the 60 mile round trip over to Pick a part with a tape measure in hand and walk the yard to see what might fit. The bolt circle on the pump is not a problem as the pump that is on there has both the small and large bolt circle and the fan and spacer have slotted holes.

The fan is aftermarket and is about as large as I can fit in there. it is a 7 blade flex which will move a lot of air when you get it spinning and the radiator is a 4 row aluminum. I know from experience that those do generally work well but they are somewhat resistant to air flow which is why I put on the flax fan in the first place.

I did post the pulley question on a Pontiac forum, so far without response. i have checked with all the aftermarket pulley suppliers and no one has anything for the pre '65 Pontiac. I guess this is the challenge of having one of the less popular old cars. The problem is that most water pump pulleys have more offset than this one. It is only 1 3/4" from the face of the pulley to the center of the first belt groove.

The joy of it all

Re: strange cooling

Posted: Thu Jul 12, 2018 9:16 am
by bohica2xo
Try the guys at French Lake Auto Parts in Annandale MN

320-274-8497 or

They still have lots of older stuff. I just got some 1965 Barracuda trim parts from them.

I just had a look at my pile of early mopar pulleys. A couple of them are close to that short, 1.875 face to groove center, but they are single belt units. Some mopar B & RB block stuff is shorter, and two groove. I only have LA motor stuff on the shelf.

Bolt circle is 2.062 diameter, with a 5/8" pilot on v belt mopar pump pulleys. 2.3L Fords have the same spec, but 302 V8's have a 1.75o bolt circle - so we rotate those 45 degrees & drill new bolt holes. You don't need a "Pontiac" pulley - you need one with the same back spacing.

Here is a common 440 (RB) pulley:

Re: strange cooling

Posted: Thu Jul 12, 2018 3:42 pm
by grumpy old man
I realize that the pulley does not need to be Pontiac just needs the right dimensions. Just thought about it. If I can find the right size pulley with a longer offset could I put a spacer behind it? Wonder what diameter that mopar pulley is? As near as I can tell trying to reach all the way down there past all the belts and stuff the crank pulley is 6" plus or minus so a 6 " water pump pulley would put the water pump at crank speed which should not be a problem.

Re: strange cooling

Posted: Thu Jul 12, 2018 11:10 pm
by bohica2xo
I believe there are 5.75 diameter & 6.25 diameter 2 groove Mopar pulleys for the big block. Everything from Barracudas to Motorhomes had 440's.

Also the 472 Cadillac had a really shallow 2 groove water pump pulley.

You could run a short spacer behind a deeper pulley, as long as the back side of the pulley clears the pump body.

Do you need a single groove or double groove unit?

March actually makes Pontiac pulleys...

I know you have an earlier engine but March has been able to help me with some odd projects before.

Re: strange cooling

Posted: Fri Jul 13, 2018 9:53 am
by grumpy old man
I just had a conversation with cvs racing. They have a ton of pulleys I just need to get the accurate measurements of the existing pulley. The measurements I have are estimates holding a tape in there with the pulley on the engine. Once I have the accurate measurements I will also check with march. The 5.75 sounds good as that will give the pump a slight overdrive which would probably be a good thing as slow as this engine turns on surface streets. All of the Pontiac pulleys that cvs has are slightly over 6 inches. Thanks for all the information, when I finally get this thing sorted out I will post the results.

Re: strange cooling

Posted: Mon Jul 23, 2018 4:28 pm
by grumpy old man
OK so I got a pulley from CVF racing, it is a AMCL2WP. It fits some model(s) of AMC and Jeep. The pulley is just over 6 inches but the backset and pulley spacing is almost perfect, i just needed to space it out .060 to get the belts lined up and do a little grinding on the pump ribs. I was going to give it the ultimate test today by driving it to a job downtown in the gruesome LA traffic, but up jumped the devil. I put the pulley on Saturday and drove the car Sunday. Engine temp was doing great but the nozzle temp started climbing back up to 60. I thought here we go again. So I parked it in the garage and when I got the time I put the gauges on it to see what was happening, 10 psi in the system. All the gremlins I have chased on this thing the one thing I have not had is a leak, did I get a bad condenser? It was doing fine for better than a week until I changed the pulley and the additional air flow should have brought down the pressures so what the he...? I pulled the hose off and the o ring looked good soooooo.

I am leaving town Wed AM for a week so will not have a chance to look at it until I get back. What ever I did to piss off the A/C gods I hope that I can figure out what to do to make them happy. Maybe I can sacrifice my ex wife in an active volcano.

Guess I need to bite the bullet and get another leak detector. My ancient Snap On unit died and there were no longer parts available for it. The saga continues.

Re: strange cooling

Posted: Tue Jul 24, 2018 3:44 pm
by ice-n-tropics
I documented and installed a modified Vintage Air HVAC in a 1961 Pontiac Bubble Top 389 with a Sanden SD5H14 compressor which is covered in Chapter 10 of "How to Air Condition Your Hot Rod" (book available from Vintage Air). I was able to install a adequate modern parallel flow condenser with heat dissipation capacity equal to the evaporator heat absorption plus the energy input to the relatively small 138 cc swept volume compressor (30% of evaporator BTU). No pusher fan req'd.
Compressor drive ratio is 1.39 to 1 and non interference engine red line is 4800 erpm with triple carburation. Compressor recommended max rpm is 7,000 rpm, therefore compressor should survive at 6,672 crpm at top engine rpm.
You may be interested in my custom air discharge cold air bezel.

Re: strange cooling

Posted: Thu Jul 26, 2018 5:26 pm
by grumpy old man
I looked at the system Tuesday afternoon and found that i had not tightened the inlet connection on the condenser, you get old and your brain leaks. I put a new o ring in it evacuated it and put it under can pressure, sprayed it with a soap solution and no bubbles so went ahead and charged it up. I do have another question, is the stuff they are shipping to California different than the old stuff? I scored on some old r134 cans at a good price so I bought it, It is Dupont so I believe it should be OK stuff. The reason I ask is that I have been using the original 98 Crown Vic fill spec as a base line, 38 ounces. The cans are 12 oz each so 3 cans would be 36 oz, I put in one can and the clutch stopped quick cycling but the pressures were low. I put in the 2nd can and the low side was up to 45 psi and high was over 200 at idle. speeding up the engine would drop the low side into the 20's with the high side approaching 300 but it would not get the low side down enough to cycle the clutch. I have been away from this long enough that I am not going to make any dogmatic statements but those pressures seem to me to look like overcharge with only 24 oz in the system.

I took it out for a drive, weather just short of the hundreds, and as long as I was traveling over 45 mph the nozzle was a steady 40 degrees. As soon as traffic would slow down or stop the nozzle would climb about 10 degrees. Engine temp was solid at 190 so I have improved air flow enough to cure the engine temp but the A/C is still warming up at idle. Parked it and left town the next morning.

Is there something I am missing? I now have a parallel flow condenser that is around 20X22, a retired cop friend of mine that used to moonlight in an A/C shop found it for me, it had the correct hose connections so that is what is presently in there. Is it possible that it does not have enough cooling capacity, am I possibly overcharged at 24 oz or ????? If it will help I will purchase one of those Cad condensers, looking at pictures and going by your dimensions I can get it in there, I will just need to get two new hoses made. If It will help is there a preferred vendor? Looking on e bay I can find them at widely varying prices which makes one wonder if the cheaper ones can possibly be as good as the expensive ones. If it might help I will order one while I am away and when I get back I will put it in.

Still trying to appease the A/C gods.

Re: strange cooling

Posted: Thu Jul 26, 2018 7:00 pm
by bohica2xo
A common problem with upgrading to a PF condenser is reduced charge requirement. This happens with GM trucks - they superseded a condenser with a better one, and the system capacity went down by 6 ounces.

You may be close tp the right charge. At 100f ambient a high side of 270 to 300 is ok, not the best but not uncommon either. At 115f & 2000 engine rpm on a full load test here in the desert 375 psi can happen. Crown Vics of that era were taxis around here, and I don't recall any of them being meat lockers.