#81  
Old 09-29-2012, 05:21 AM
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Originally Posted by jray1 View Post
Not the water crossover. I was talking about the heat crossover in the center of the intake that runs under the carb it was reading 270.
That is a different story! Not a problem imho.

Karl


  #82  
Old 09-29-2012, 02:02 PM
jray1 jray1 is offline
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Originally Posted by 72LuxuryLeMansLa. View Post
That is a different story! Not a problem imho.

Karl

Ok. I was just wondering if I blocked the crossover off I might help the temps.

  #83  
Old 09-29-2012, 02:47 PM
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Ok. I was just wondering if I blocked the crossover off I might help the temps.
That's different. Blocking off the heat crossover will certainly lower the temps in the intake manifold which will reduce the temps in the fuel air charge. I would imagine that this would help to bring down over all engine temps but I am not certain. I know that SD Performance blocks off the cross overs by filling them with aluminum when they rework iron heads. They do things for a reason.

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  #84  
Old 09-29-2012, 06:49 PM
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If it's an egr crossover than it should be reading hot because it's exhaust gasses. I would block it off to keep the intake cooler but, I have tried to run non-egr intakes on egr heads and that caused very quick overheating so research it first.

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  #85  
Old 09-30-2012, 12:30 AM
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Sorry if I missed this, but I read through the posts pretty quickly. Did anyone mention that 68 and earlier with the 8 bolt pumps require two divider plates inside the pump housing? All I saw was the correct mention that there is only one gasket.

Also, you are much better off putting an expansion plug in the rear of the passenger side head than running the hose back to the crossover or water pump housing. All you are doing is robbing that head of coolant flow that goes from rear to front like the driver's side does. Take a look at any Pontiac service manual and note the diagram of coolant flow in the Pontiac engine.

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  #86  
Old 09-30-2012, 07:20 AM
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Originally Posted by jray1 View Post
Where could I have an air pocket if I have the thermostat gutted so its just a slight restriction and no holding the water back?
You'd be surprised.

An easy way to make sure that there is no air bubble is to:

1: Drain the coolant to below the t-stat line.
2: Remove t-stat housing and gutted t-stat.
3. fill the water crossover with water until it is at the t-stat line.

At this point you could spin the water pump to see if the area from the intake manifold to the timing cover has fluid in it. or use a coat hanger to "stab" and air bubble if there was one.

Fart bubble in your butt is similar. Gotta move to pop it!!

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  #87  
Old 09-30-2012, 09:52 AM
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Quote:
Originally Posted by 1967Tempest View Post
You'd be surprised.

An easy way to make sure that there is no air bubble is to:

1: Drain the coolant to below the t-stat line.
2: Remove t-stat housing and gutted t-stat.
3. fill the water crossover with water until it is at the t-stat line.

At this point you could spin the water pump to see if the area from the intake manifold to the timing cover has fluid in it. or use a coat hanger to "stab" and air bubble if there was one.

Fart bubble in your butt is similar. Gotta move to pop it!!
Perhaps the most informative yet simple and abraisive yet sensitive (being a coated hanger, could be used as a pick up line ) post I've read in a long time!

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-and wheels.
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  #88  
Old 09-30-2012, 03:00 PM
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The possibility of an air bubble is grossly overrated. Even if the passage between the pump and manifold has been blocked, the pump will quickly route any air entrapment. For that matter this passage is about an inch down in the water pump cavity so there will always be an air bubble present on initial fill. Think about this - if air were a problem, then the heads would quickly overheat since there are about a dozen places per head that will trap air on the initial coolant fill up. What quickly happens is the air is displaced by both force and temporary saturation in to the coolant. Proof of this is that the radiator level always drops after the first good run of the engine - the air ends up at the top of the radiator and the coolant has replaced the air inside the engine. It does help to keep the top radiator hose at or a little below the top of the radiator, but this is after the coolant has completed its job, and the only handicap is a very slight reduction in coolant capacity.

The thermostat's only purpose is to maintain sufficient heat in the engine. First thing to do when you have a heating problem is to remove the thermostat. The Chevy tale about running hotter without a thermostat does not apply to a Pontiac engine. I have temporarily run several dozen engines sans thermostat when chasing down problems, and in every case the engine ran as cool, or cooler than a properly functioning thermostat.

Here's the latest rub - I've found thermostats from every manufacturer that were defective right out of the box, and the problem has compounded lately. So far the record is four thermostats in a row that were so far off that they couldn't be used. Problems included opening up to 20° late to only partially opening. So remove the thermostat and see if the engine runs cooler. If it runs the same, then your thermostat is good. Otherwise get another one, and test it out on the stove with a pan of water and a known accurate thermometer.

I like to think that I've done all my reading and all my homework on cooling, and that I have tested out everything I have read, and weeded out ideas that don't work. It comes back down to not believing everything you read on the internet. There can also be a coexisting problem that the person solves and incorrectly attributes the solution to the wrong fix. I started looking for answers 25 years ago with the purchase of my second '67 GTO. This one had A/C that didn't work, and I would have to pull over and let the engine cool off if I took it out past a 10 mile drive. This car already had the longer radiator and 19.5" fan. Fast forward to today, and the car runs at 165° with the air conditioning blasting cold air on our 100°+ days running around on the flat. Going up long, steep grades running the A/C on these hot days will still only get the car up to 180°. Best step forward out of all the things I changed was the divider plate fix that I read about first on PY.

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Last edited by lust4speed; 09-30-2012 at 03:05 PM.
  #89  
Old 09-30-2012, 08:33 PM
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Quote:
Originally Posted by 1967Tempest View Post
You'd be surprised.

An easy way to make sure that there is no air bubble is to:

1: Drain the coolant to below the t-stat line.
2: Remove t-stat housing and gutted t-stat.
3. fill the water crossover with water until it is at the t-stat line.

At this point you could spin the water pump to see if the area from the intake manifold to the timing cover has fluid in it. or use a coat hanger to "stab" and air bubble if there was one.

Fart bubble in your butt is similar. Gotta move to pop it!!
Made me laugh.

  #90  
Old 09-30-2012, 09:01 PM
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Quote:
Originally Posted by lust4speed View Post
The possibility of an air bubble is grossly overrated. Even if the passage between the pump and manifold has been blocked, the pump will quickly route any air entrapment. For that matter this passage is about an inch down in the water pump cavity so there will always be an air bubble present on initial fill. Think about this - if air were a problem, then the heads would quickly overheat since there are about a dozen places per head that will trap air on the initial coolant fill up. What quickly happens is the air is displaced by both force and temporary saturation in to the coolant. Proof of this is that the radiator level always drops after the first good run of the engine - the air ends up at the top of the radiator and the coolant has replaced the air inside the engine. It does help to keep the top radiator hose at or a little below the top of the radiator, but this is after the coolant has completed its job, and the only handicap is a very slight reduction in coolant capacity.

The thermostat's only purpose is to maintain sufficient heat in the engine. First thing to do when you have a heating problem is to remove the thermostat. The Chevy tale about running hotter without a thermostat does not apply to a Pontiac engine. I have temporarily run several dozen engines sans thermostat when chasing down problems, and in every case the engine ran as cool, or cooler than a properly functioning thermostat.

Here's the latest rub - I've found thermostats from every manufacturer that were defective right out of the box, and the problem has compounded lately. So far the record is four thermostats in a row that were so far off that they couldn't be used. Problems included opening up to 20° late to only partially opening. So remove the thermostat and see if the engine runs cooler. If it runs the same, then your thermostat is good. Otherwise get another one, and test it out on the stove with a pan of water and a known accurate thermometer.

I like to think that I've done all my reading and all my homework on cooling, and that I have tested out everything I have read, and weeded out ideas that don't work. It comes back down to not believing everything you read on the internet. There can also be a coexisting problem that the person solves and incorrectly attributes the solution to the wrong fix. I started looking for answers 25 years ago with the purchase of my second '67 GTO. This one had A/C that didn't work, and I would have to pull over and let the engine cool off if I took it out past a 10 mile drive. This car already had the longer radiator and 19.5" fan. Fast forward to today, and the car runs at 165° with the air conditioning blasting cold air on our 100°+ days running around on the flat. Going up long, steep grades running the A/C on these hot days will still only get the car up to 180°. Best step forward out of all the things I changed was the divider plate fix that I read about first on PY.
AMEN to that.

  #91  
Old 10-01-2012, 08:08 AM
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Does the divider plate mod still need to be done to the Flowkooler pump? Ever though the impellers are shrouded?

  #92  
Old 10-01-2012, 08:43 AM
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Take a video lets get some visuals. For both of you jray1 and Goatcheese.

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  #93  
Old 10-01-2012, 12:57 PM
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Originally Posted by jetdoc View Post
Does the divider plate mod still need to be done to the Flowkooler pump? Ever though the impellers are shrouded?
It helps the Flowkooler pump also. I have tested their pump with the welded plate and there was no cooling advantage over the regular pump with the plate alteration. If anything the milled down impeller inhibited low engine speed cooling. This is another case of "what works on a Chevy must work on a Pontiac" thinking. The Chevy pump is physically smaller and the Flowkooler impeller size fills up their cavity. I've never understood any manufacturer trimming down the impeller size trying to improve efficiency. Most of them claim that this reduces excess high RPM drag. To me, the point is trying to get the car as cool as it can at every point. I don't care if I'm wasting some minor horsepower loss on my street engine - just give me cooling capacity. The Flowkooler isn't a bad pump, it just isn't any improvement over the standard Pontiac design, and too much money for what you get. I've installed several PRW 11 bolt aluminum pumps and have been impressed with their quality.

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  #94  
Old 10-02-2012, 01:33 PM
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Heat crossovers are blocked, everything's back together and just idling in the shop its working perfect. Warmed up fan came on cooled for almost a minute and the temp dropped fan turned off. Now I will just have to drive it down the road to be sure it does the trick (fingers crossed).

  #95  
Old 10-03-2012, 10:21 AM
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Ran good this morning, took a lot longer to warm up but it did finally get to 190. It seems that is the best I am going to get. I did however have to back down the timing again after adding a little. I will have to try it out again tomorrow and see what it does.

  #96  
Old 10-03-2012, 10:23 AM
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Intake temps are about half of what they were On the heat crossover with the blockoffs.

  #97  
Old 10-09-2012, 08:53 AM
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Any updates?? Either of you guys?

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  #98  
Old 10-09-2012, 12:19 PM
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Took a 40 mile drive Sunday evening with temps 48-50 degrees I think and I sat at 190-195 the whole time. This was with a 3 mile pull up the mountain I live on as well. If it was 90+ degrees outside I don't think it would have stayed that cool. Another thing I have been wondering was if the original down flow worked better in this car. Maybe the crossflow could be a partial issue. Also I am waiting on an adjustable vacuum advance and will be going back to it and adjusting it to get the correct specs. Then another drive to see what happens.

  #99  
Old 10-12-2012, 01:16 PM
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Any thoughts on down flow verses cross flow?

  #100  
Old 11-08-2012, 09:12 PM
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Finally getting the 400 cooling the way it is supposed to. Went with the champion 3 row radiator and took a serious look at my rocker adjustment which was way to tight. After a total readjustment of the rockers it seems to be cooling just the way it should. Guessing it was my fault all along.

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