[J.C.you]

moroso pn:63765, if you don't mind drilling and tapping the top of your timing cover housing. You can see it in the pic.

[screamingchief]

It's also a good idea to be sure to drill a small hole (1/4" or so) at the very top of the WP divider plate if using one of those bleeds in the TC cover,that way the bleed can actually "see" both sides of the cooling system so it can bleed all the air outta the top of the TC housing.

Just an FYI.

HTH

Bret P.

[J.C.you]

Originally Posted by screamingchief

It's also a good idea to be sure to drill a small hole (1/4" or so) at the very top of the WP divider plate if using one of those bleeds in the TC cover,that way the bleed can actually "see" both sides of the cooling system so it can bleed all the air outta the top of the TC housing.

Just an FYI.

HTH

Bret P.

not sure if i agree on drilling a hole in the divider plate. The pontiac engineers would have done this to bleed air from the WP side if needed. This only would dimish the efficiency of the system in my view.

With raised port heads the hole from the intake crossover to the timing cover housing had to be plugged, thus the reason for the bleed.

[screamingchief]

Originally Posted by J.C.you

not sure if i agree on drilling a hole in the divider plate. The pontiac engineers would have done this to bleed air from the WP side if needed. This only would dimish the efficiency of the system in my view.

With raised port heads the hole from the intake crossover to the timing cover housing had to be plugged, thus the reason for the bleed.

The pontiac engineers likely counted on any trapped air on that side of the divider being pulled into the hot/engine side of the cooling system and thus being re-circulated thru the cross-over in the intake,or being sent to the radiator and expelled via the rad cap.

Any minimal residual air that got trapped up there on that side of the divider that did'nt get passed into the cooling system basically took up what they considered "dead space",so odds are they were'nt all that concerned with it,as they already knew that air is not compressible in a cooling system,thus it acts the same as a solid object would.

Talk to a savvy engineer like Tom Vaught about this if you dont believe me.

But that small hole in the divider plate does'nt hurt the cooling system efficiency siginificantly (if at all) as that wont let all that much coolant pass thru it.

And any minimal amount of coolant that did re-circulate thru the hole in the divider plate wont be hot coolant as it has'nt even had a chance to pass thru the engine at that point.

Think of it as you would an anti-cavitation slot on a oil pump or such,the idea is to give any trapped air on the high pressure side of the divider an easy/convenient escape path.

The cross-over from the intake manifold passes way more coolant than that small of a hole in the divider plate ever would,and understand that's re-circulating hot high pressure coolant back into the colder/suction side coolant.

Honestly,that divider plate mod is really not all that different than drilling some small holes in the thermostat to let it bypass any air or such.

Another thing to keep in mind here is the fact that the pressure in any closed system is exerted equally in all directions,so a pressure loss in any part of the high pressure side of the cooling system will pretty much have the same net affect.

Anyhow,if it makes a fella sleep better,just make the hole even smaller yet,the air will get thru no matter what size the hole is,just put it up as high as you can on the divider plate,same as the air bleed on the timing cover.

FWIW

Bret P.

[J.C.you]

Bret, do some testing in this area and then come back and post. Until then, speculation is just that....speculation. I could do some testing here, but do not care to risk running my engine hotter than need be. (By the way, i would like to brag alittle. This 4.5 arm engine runs 190* tops during a 40 lap feature race blasting 6800 to 7000 rpm in the straights.

Makes sense to me, maybe not you.....circulating water from one side of the divider plate to the other would do nothing to cool the engine, only make the system more inefficient, and also make the engine run hotter. One could do the math on GPM that a 1/4 inch hole would cut the cooling efficiency, but not worth the effort. Let's speculate it is only a 1 gallon per minute loss. That one gallon loss would not be good, especially on the racing i am doing. Multiply this on a street type ride over a long distance trip and the engine temp would surely rise.

[Pontirag]

it has been reported in the past that some devider plates did have small holes drilled in them. I pulled one off a '69 428 back in the 80's. I cannot confirm that it came from the factory that way but I knew the history of the car and it vary unlkely the owner did it.

a search will bring this subjet up where others also state that they had come across similar bleed holes in thier devider plates. seems they only came on HP engines.

[screamingchief]

Well JC,then you wont ever wanna run the "high end" Evans water pump then,as they are also drilling that hole in the divider plate to be able to use the bleeder valve that comes with their water pumps.

The only difference here is their bleeder valve is on the pump itself,and not the TC cover.

http://forums.maxperformanceinc.com/...4&postcount=16

Originally Posted by Tom McQueen

The purge valve is for eliminating the air pocket at the top of the water pump. Thats a hi spot where air can/will collect. The Evans pump comes with a diagram that also details where a small hole needs to be drilled in the divider plate so you can use the purge valve to effectively burp both sides and get all the air out.

Guess those Evans engineers are wrong on that deal too then...



Bret P.

[Region Warrior]

GM part #10070107 works great.
Free if you hit the pic-n-pull. On front bypass pipe 4 and 6 cyl cars.

Not get'n into the divider plate side issue. Already know from testing

[J.C.you]

Originally Posted by screamingchief

Well JC,then you wont ever wanna run the "high end" Evans water pump then,as they are also drilling that hole in the divider plate to be able to use the bleeder valve that comes with their water pumps.

The only difference here is their bleeder valve is on the pump itself,and not the TC cover.

http://forums.maxperformanceinc.com/...4&postcount=16



Guess those Evans engineers are wrong on that deal too then...



Bret P.

let me see, i remember a quote from somewhere?.....engineers do stuff for reasons....Maybe so, but engineers are not infallable and screw up like anyone else. Engineers also will to try capitalize on the latest quirk for a old mousetrap, to sell to the unknowledgable public, even if it works or not. I will look at their website to see if they have done any real world testing or just selling a quirk.

Bret, thanks for the attempted help anyway. I'll just keep on racing. How many races you ran in the past 5 years?

[russosborne]

Here's a link to a new one of these "GM part #10070107 works great." New price is less than $9, don't know about shipping.

http://www.gmpartsdepartment.com/par...&siteid=214533

Was looking for a picture of it, anyone have one?
Thanks,
Russ

[Region Warrior]

"Anyone have one?"
Ya, 2 on engines, and a spare in the tool box.

[Region Warrior]

If engineers had to repair what they design, bet vehicles be ALOT easier to work on.

[russosborne]

Originally Posted by Region Warrior

"Anyone have one?"
Ya, 2 on engines, and a spare in the tool box.

OOPS, my bad. I meant have a picture of one so I know what to look for.

Thanks,
Russ

[Sirrotica]

J.C. is right on with cooling a Stratostreak engine on an bullring style oval track, I don't think any other form of motorsports will test a Pontiac cooling system except maybe road racing would be a close second. If there is any weakness in a Stratostreak cooling system, it will be shown on a small oval track. Anything that helps maximize the cooling system will be helpful in this type of application no matter how small a benefit it has.

Bret, as far as Pontiac engineers doing the best possible with cooling systems, The gusher reverse flow system (55-59) was much more efficient than the present system is and Pontiac engineers had it up and running and proven and for some unknown reason (perhaps bean counters) abandoned it and we have had to band aid the secondary choice ever since. I guess even back in 59 someone either thought it was overkill or it wasn't really necessary for a mass produced street driven engine and they could get by with the less efficient system we now have. So much for the engineers at Pontiac making the most out of the cooling system. I know some people on here have looked into resurrecting that system, however I have not read about anyone having a system up and running presently.

BTW J.C. how's the racing going with your modified? Any pictures?

[Region Warrior]

Originally Posted by russosborne

OOPS, my bad. I meant have a picture of one so I know what to look for.

Thanks,
Russ

Can send ya a phone pic of one we keep in stock.
Or fax a pic from our parts cat on what pipe to look for in wreck'n yard.

[screamingchief]

Originally Posted by J.C.you

not sure if i agree on drilling a hole in the divider plate. The pontiac engineers would have done this to bleed air from the WP side if needed. This only would dimish the efficiency of the system in my view.

Sigh,I did'nt bring the engineers into this discussion,see ^^^^ above comment.

JC was the one that brought the engineers into this discussion first,implying that when the pontiac engineers chose to do something,that it had to be right.

And now ya'll are saying that the engineers cant do anything right...

Well,,,you cant have it both ways,,,so which is it now guys???

Originally Posted by J.C.you

Bret, thanks for the attempted help anyway. I'll just keep on racing. How many races you ran in the past 5 years?

I'm sure even if I were the winningest racer here,we'd still be arguing about this.

I'm not here to change anyones mind,especially the closed ones.

It's simple really,dont like the idea,dont do it.

Yeah sure we've all done things that the pontiac engineers did'nt do,so I dont see why is everyone getting so uptight about this deal?

I just tried to explain the reasoning behind the putting the hole in the top of divider plate,and lotta good that did,as now everyone is getting all bent outta shape over something that's really pretty simple.

If that small hole in the divider plate makes a noticable difference in any cooling systems overall performance,then the system was clearly marginal to begin with,and you almost certainly got bigger fish to fry than that small hole in the divider plate.

And any talk here about that affecting the cooling system flow is a bit pointless too,as unless a person is running an electric water pump,then their cooling system's flow in terms of GPM is'nt fixed anyways,mechaincal water pumps are variable output pumps based on the engine RPM and pulley ratios,so if some small drop in the systems GPM flow hurts the cooling system performance (for whatever reason),then that problem should be easy enough to correct via the pulley ratios being used,so long as you dont go too crazy and push the pump into cavitation,and if that ends up being the case,then the current water pump was inadequate in terms of GPM to begin with.

Cooling systems are'nt all that complicated,but it helps to understand the fundamentals & dynamics that these systems operate under and keep an open mind to avoid complications and such.

And I never suggested that JC was having any problems with his cooling system either.

I just felt that others reading this thread might find that bit of info as having some merit.

Have fun guys,now ya'll can go find someone else to be your punching bag.

Bret P.

[Skip Fix]

My old Honda Accord had one in the thermostat housing.

[J.C.you]

Originally Posted by Skip Fix

My old Honda Accord had one in the thermostat housing.

skip, are you recommending a accord housing for the poncho?

[Region Warrior]

Wow, someone pulled SC's knob.
Chill out buddy

So...considering Pontiac's design, how does the air escape from w/p hsg on drain-n-fills?

[Tom McQueen]

The absolute best mechanical Pontiac water pump is the Evans. This pump comes with a bleeder already installed, and instructions on where to put the hole in the divider plate. Evans is probably one of the more knowledgeable cooling system companies. Their stuff is in a lot of circle track cars.

For street use, the Pontiac engineers didnt think the hole was necessary. The engineers at Evans, that live in the racing world, decided it was necessary. Engineers absolutely do things for a reason.