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Thread: Cooling the Pontiac V8

  1. #1
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    Default Cooling the Pontiac V8

    I know from reading about it on numerous Pontiac forums that I am not the only guy to have had problems trying to keep a Pontiac engine cool. I remember back in my early racing days we would push our cars all the way from back to front in the staging lanes. We'd wait til the last possible second before starting the engine, in order to keep from overheating before the pass was complete.

    Then, when we got back to the pits, we'd start spraying down the water crossover, water pump, hoses and radiator with ice water in hand pump pressure sprayers. And if it was in the later rounds, with very little turnaround time, we'd pack the intake manifold with ice as soon as the car stopped. Plus, we'd unhook the bottom radiator hose, drain out all the hot water and refill with cold water. We'd also drain the water out of the fuel line cool can and refill it with ice.

    I remember one particularly hot night in Tyler Texas. They were having an IHRA points race. It was the middle of the summer, and the temp had been well over 100 degrees that day. During the latter rounds of eliminations, the temp was probably still in the mid 90's. TJ was still in, with her '68 Bird. As with most tracks, they were pushing to finish the race. So we had VERY little down time in the pits, between rounds. So, as soon as she pulled it back in from a round win, we immediately dumped the hot water, filled the rad with ice water, and packed the intake with ice. We also started spraying the water crossover and water pump with ice water.

    We never cranked it back up til it was time to pull out onto the track. Instead we pushed it all the way from the pits and up thru the staging lanes. Then, at the last possible minute, we quit spraying and started drying up all the water we could, so that we would not get DQ'd for gettin water on the track. Needless to say we were working fast and furiously. Well, was it worth all that work ? Sure it was. She won the race, which was her biggest win to that date. Plus, she got her pic in the IHRA paper called the Drag Review. I'll post the pic.

    But, even tho it was worth the extra work, it would have been more enjoyable(if such is possible) if we could have just sat around and talked between rounds. Then, when they called her class up, she could have just fired it up and drove to the staging lanes. Well, the parts and info exist today to rig up a Pontiac so that it will run cool and not require all that thrashing that we did.

    Since there are no threads or info on this subject under "Cooling Systems", I'll start this thread to share info on the parts and mods needed to make your Pontiac run cooler. In the coming days, I'll share all the part numbers and the best sources I can find, as well as links to proven cooling mods. If any of ya'll know of better parts, prices or links than those I post, then by all means post your info on this thread. Together, maybe we can help cool some of those hot rod Pontiacs out there !
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    Last edited by big D; 10-08-2014 at 12:39 PM.

  2. #2
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    Default The Pump

    The water pump is the heart of the cooling system. It doesn't matter how big your radiator is, if your water pump can not pump enuff water thru it to cool your engine. So, I recommend using a high volume alum water pump. There are several good ones on the market. A stock type iron pump with a stamped impeller, will not move enuff coolant to do the job. So here are the links to some Pontiac alum pumps.

    Here's the cheapest alum pump I can find. It's a GMB brand. The description of it calls it standard volume, but high flow. Might work for guys on a budget.

    http://www.summitracing.com/parts/gmb-130-1280al

    Here's one listed as a Milodon brand. One review, said this is the same GMB pump listed above--even has GMB stamped on it somewhere. Cannot confirm. If so, then the Milodon is the same pump for over twice the price. :( Description says it is high volume.

    http://www.summitracing.com/parts/mi...w/make/pontiac

    This next one is listed as a PRW brand. It is only a few dollars higher than the Milodon above. The picture that is shown of it, looks to be exactly the same pump as the GMB and Milodon.

    http://www.ebay.com/itm/PRW-Pontiac-...p2054897.l4275

    This next one is considered "King of the Hill" by most. It's a FlowKooler brand. But it looks exactly like the GMB and Milodon. The 1st review of it reveals why. It is indeed a GMB housing.(GMB may be one of the few Pontiac pump housings being made today--don't know) But it has a 16 blade impeller ! Now that should move some coolant. This is my choice for all who can afford it.

    http://www.summitracing.com/parts/br...w/make/pontiac

    Edlebrock sells Pontiac pumps. Don't know who the supplier is. The housing is not the GMB model used on the above pumps. It has the Edlebrock name cast into it. But these are well over $200, so I don't recommend them.

    For racing, many use an electric pump, like the Meziere. They are quite expensive, but allow cooling in the pits, along with electric fans. Now this set-up would have saved us lots of work, back in the old days. Just hook up the batt charger and let the engine cool between rounds, while we set around and enjoy the race. But, I don't recommend this pump for street use.

    http://www.summitracing.com/parts/me...w/make/pontiac
    Last edited by big D; 10-09-2014 at 03:54 AM.

  3. #3
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    Default The Divider Plate

    The '69 and later 11 bolt Pontiac water pump is designed to work with a metal divider plate between the pump and the timing cover. Without this plate, the pump is practically useless. It will not pump coolant thru your engine. This plate has two holes which seal off against rubber inserts in the timing cover. And a gasket goes on each side of the plate. These plates are available in stainless steel, at a higher cost, of course. But they will last longer.

    http://www.ebay.com/itm/like/190701812782?lpid=82

    The rubber inserts come in a pair of metal sleeves which press into the timing cover.

    http://www.ebay.com/itm/GM-Water-Pum...-/190704398643

    If your timing cover is bad, there are several sources for new ones. Some of them come with new sleeves and a divider plate.

    http://www.summitracing.com/parts/aaf-all90019

    http://www.ebay.com/itm/NEW-PONTIAC-...-/311108684876

    BUT, even with a high volume pump, a new divider plate, sleeves and timing cover, your pump will not pump efficiently if the gap between the plate and the pump impellers is too large. Some gaps have been discovered that were 1/4 inch or more. This gap MUST be reduced in order for your pump to function correctly. The way to reduce this gap is quite simple. You must tap on the plate with some sort of hammer, in order to bend it in closer to the impellers. Some sort of soft rubber, wooden or plastic mallet will probably work better than a metal hammer, so as not to damage the plate. There are several good sites explaining this mod, including a video. I'll post some links that should explain the procedure to those who are not familiar with it.

    http://www.wallaceracing.com/water-pump-mods.php

    https://www.youtube.com/watch?v=UdyAo5546JQ

    http://forums.performanceyears.com/f...d.php?t=411256

    http://hardcorepontiacs.com/forum/sh...-divider-plate

    https://pontiworld.com.au/usgmsp/pro...oducts_id=1017

  4. #4
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    Default The Fan

    OK, once you have a good pump on your motor and have the divider plate clearanced correctly, It's time to choose a fan. Many choose a clutch fan. That's fine if you prefer. But I prefer a 7-blade flex fan. Why ? Max air flow. I like overkill, when it comes to cooling. If you have more air coming thru the rad than you really need, what does it hurt ? I rather have too much and keep it cool at all times than to have a borderline system that might not cool it in 100 degree weather, idling along in slow traffic with the AC blowin wide open. :(

    I think, by now, that everybody knows you need to run a good fan shroud. So I won't spend any more time talkin about 'em. Summit and most of the resto places sell shrouds. Use one !

    Measure the shroud you'll be using and see how big your fan can be, without interference. Then buy the biggest 7-blade flex fan you can find, that will fit in the hole. And make sure that you use a fan spacer long enuff to place the fan just inside the shroud. If it is outside, it will suck some air from outside the shroud instead of thru the rad where it will do some good.

    There are at least 2 major vendors of 7-blade metal flex fans--Hayden and Flex-a-Lite. Either should be fine. BE CAREFULL ! Most of these type fans I've run across have very sharp edges that will cut you quick ! Here's what I can find online right now.

    http://www.summitracing.com/parts/flx-1818

    http://www.summitracing.com/parts/hda-3718/overview/

    http://www.ebay.com/itm/3718-HAYDEN-...-/221533818731

    http://www.amazon.com/Hayden-Inc-371...bs_15725371_20

    http://www.summitracing.com/search/p...al-fan-spacers

    Again I'll say, if you prefer a clutch fan, use one. They make 7 blade clutch fans and high performance clutches. But if you use one, check it occasionally to be sure it is still working properly. That's just one more part that can wear out. :(
    Last edited by big D; 10-10-2014 at 06:54 AM.

  5. #5
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    Default The Radiator

    This subject can be quite controversial. Lots of guys hate all things made in China. So let me say before I start, if you want high $ USA made parts and can afford 'em, great--buy 'em.

    But most Pontiac street guys are on a budget and need to stretch their dollars as far as possible. So with this in mind, I'll mention what I consider good buys on radiators. 1st I'll say that unless you are building a numbers matching show car, you should use an alum rad. They are proven to be more efficient than the old brass GM rads.

    And, the prices for the Chinese rads are very reasonable. Many 2 row rads are less than $200. 3-rows just over $200 And 4-rows are around $300 or a bit over. Again, as I've mentioned, when it comes to cooling, I like overkill. If a 2 row will work just fine in most situations, but not in the 100 degree, idling along in slow traffic, with the AC blowing situation, then it is not enuff.

    Now when the subject of alum rads comes up, some guys are always bringing up the fact that all two row rads are not created equal. For example a 2-row with 1" wide tubes will cool better than one with only 1/2" tubes. Also, there are double and triple pass rads. Some say the double pass works good, but the triple pass slows the coolant down too much. If you decide to use a double pass, keep in mind that both hose outlets will be on the pass side. So you'll have to plumb the upper hose to fit.

    However for most applications, a GOOD 3 or 4 row will work just fine. Since I like overkill, I say go with the 4-row. Some say they are too wide and there is not enuff air flowing thru them to cool efficiently. But we have already addressed that subject. A 7-blade fan, positioned properly inside a good shroud will suck plenty of air thru the rad.

    So, with all this in mind, lets look at some possible alum rads that will cool your hot Pontiac. Most of the time, the best prices I can find on alum rads are on Ebay. And some of the best buys seem to be the Champion brand. I've read that some have had problems with these a few years back. But I've also read of guys who have had great results using them and many have one in all their Pontiacs.

    I usually go to the Brand's website to get the part number for the part I wanna look up. Then you can Google that part number and many times find the best prices that way. So, for an example, let's look up a bolt in 4-row, with auto trans cooler provisions, for a 1st gen Bird. OK, a bolt in 4-row is part number MC370. You can click on this link and see all the specs.

    http://www.championradiators.com/Pon...1967-1968-1969

    Then Google this part number and see what turns up. Champion radiator #MC370.

    Here's the cheapest one I can find right now. it's $280.

    http://www.performancecooling.com/se...9-Chevy/Detail

    But their are other brands. Here's a 4-row for $310.

    https://www.radiatorexpress.com/prod...HekaAnfu8P8HAQ
    Last edited by big D; 10-11-2014 at 05:13 AM.

  6. #6
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    Default Auxiliary Fans

    Now here is another part of my overkill reasoning. For those extreme situations, I like the idea of having an auxiliary pusher fan in front of the rad. A good one will help push more air thru the rad, which will provide just a bit more cooling. Probably a good 16" will be adequate. You must buy one that is listed as reversible. Again, as with many other things, there are cheap Chinese fans and high $ USA fans and everything in between. I'll post the links to a few in different price ranges.

    But the main thing is the mounting. DON'T use the plastic ties that go thru the rad core to mount the fan ! I bought a bracket car that had the fan mounted this way and it wore a hole in one of the tubes, causing a leak. Instead, build a metal frame out of thin angle or strap, to mount the fan. I saw some thin angle with a lot of holes in it, the other day at a hardware store, that might work. For a pusher fan, it does not need to be touching the rad. So leave enuff space so that the fan will not rub the rad. The mounting points will be different on each type of car.

    Here's a piece of the thin angle with holes I mentioned. It is probably sold at Lowes, Home Depot, online and at most stores that sell hardware.

    https://www.fastenal.com/web/products/details/41183

    I'd rig up a simple HD toggle switch to turn the fan on when needed. But be sure and use large enuff wire, and a fuse in the loop. Some of these fans can draw a lot of juice.

    Here's a long list of reversible 16" fans. Many of 'em will push 3000cfm. Those should provide some extra cooling. They're priced from cheap to around $150 or so.

    http://www.ebay.com/sch/i.html?_odkw...e&_sacat=33600

    This one looks decent for $37. How long will it last ? Who knows ?

    http://www.ebay.com/itm/BRAND-NEW-HE...411643&vxp=mtr
    Last edited by big D; 10-12-2014 at 07:36 AM.

  7. #7
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    Default Thermostats

    For racing, we ran gutted tstats during the hot months. But for the early and late season races we ran a 160 degree. However, I think that most agree that a 180 degree is best for street use, in most areas. Now if you live in an area which has very cold winter temps, you may want a tstat that will make your heater blow a little warmer. But regardless of what temp you choose, ALWAYS test it BEFORE installing. There have been LOTS of new and old tstats that would not open at all.

    So, how do you test a tstat ? I'm glad you ask. Put it in a pan of water on the stove top. Turn up the heat. After the water begins to heat, put a candy thermometer in it. Watch the tstat closely. You can tell almost exactly the temp when it opens, if in fact it opens at all.

    And a used tstat can quit opening at any time. They are just mechanical devices, which can cease to function at any time. Back when I drove trucks everyday, I had more than one tstat fail, out on the road. When that happened, I'd just pull it out and finish my route.

  8. #8
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    Default

    Best cooling mod you can do to a Pontiac is install a set of CV-1 Heads ... and a Moroso restrictor plate system instead of a tstat, and big fat BeCool radiator ... you'll be in good shape then ...

  9. #9
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    Default CV1 -- BeCool

    Quote Originally Posted by Anderson Port Development View Post
    Best cooling mod you can do to a Pontiac is install a set of CV-1 Heads ... and a Moroso restrictor plate system instead of a tstat, and big fat BeCool radiator ... you'll be in good shape then ...
    Yeah, that's great for those who have that much to spend on their engine. But, contrary to popular belief, most street only guys, with hard street tires neither want nor need 600hp. I think it's great that Pontiac guys can now make well over 1000hp with aftermarket parts. But, the reality is that most guys can't spend that kind of $$.

    And it's these guys who are restoring these old cars who are keeping Pontiac alive, NOT the deep pocket racer with 600hp+ engines. I don't have any numbers to point to. But I'd just take a wild guess that for every high dollar alum head Pontiac engine, there are at least 50 400 or 4.25" stock block strokers with 6x iron heads, and the dreaded Chinese parts.

    This is not a put down to anyone. If you got plenty to spend on your engine, then, by all means, buy the very best of everything, and no Chinese parts at all. For the rest of us, there are still some 400 blocks, 6x heads, and 4.25" Chinese stroker kits, which will make over 400hp, 500ft lbs of torque, and will burn hard street tires unmercifully. I'm guessing that by now there are thousands of these motors in service today.

  10. #10
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    Default

    Quote Originally Posted by big D View Post
    Yeah, that's great for those who have that much to spend on their engine. But, contrary to popular belief, most street only guys, with hard street tires neither want nor need 600hp. I think it's great that Pontiac guys can now make well over 1000hp with aftermarket parts. But, the reality is that most guys can't spend that kind of $$.

    And it's these guys who are restoring these old cars who are keeping Pontiac alive, NOT the deep pocket racer with 600hp+ engines. I don't have any numbers to point to. But I'd just take a wild guess that for every high dollar alum head Pontiac engine, there are at least 50 400 or 4.25" stock block strokers with 6x iron heads, and the dreaded Chinese parts.

    This is not a put down to anyone. If you got plenty to spend on your engine, then, by all means, buy the very best of everything, and no Chinese parts at all. For the rest of us, there are still some 400 blocks, 6x heads, and 4.25" Chinese stroker kits, which will make over 400hp, 500ft lbs of torque, and will burn hard street tires unmercifully. I'm guessing that by now there are thousands of these motors in service today.

    ... I hear ya big d, but if you consider parts, porting, & machine work its very easy to spend over $2k on heads ... now you're not that far away from CV-1'S ... and 700hp+ is easily attainable on a factory block ... if you don't want that much power, just put in a smaller cam ...

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