# running too COOL?



## Instg8ter (Sep 28, 2010)

I know this is not usually the problem with our Pontiacs but with the three core radiator and the tight clearance on the water pump divider the beast is running no higher than 165 with a 165 thermostat even when pushing it and on hot days (88). I am worried running this cool i am not getting peak efficiency on combustion and am gonna be fine tuning on wednesday should i grab a 185 stat to get the fires burning a little hotter?


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## geeteeohguy (Feb 2, 2008)

165 is a tad too cool, IMO. 180-195 is where you ideally want to run. As I've said, even 210-215 is actually ok. Try the hotter 'stat. You must have one hell of a cooling system! Congrats on that one, not easy to do!


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## Instg8ter (Sep 28, 2010)

Thanks GeeTee i seem to remember us having this talk before and wanted to make sure, yes i have been running it through teh paces and took it on a med length drive today over a few hills and pushing it up the rev range for break-in and cannot get it to budge over 165, will grab a 185 tomorrow.


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## 68greengoat (Sep 15, 2005)

My bud's '68 400 runs at 165. I was shocked too. I'm right around 190.


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## Eric Animal (Oct 28, 2007)

Brian, I woulsd go to a 180* stat also....I always thought it was impossible to get a Pontiac to run that cool! I have a 160* stat in mine....It gets to 180-190with NO fans running...when I turn on 1 fan, it cools to 160* and stays there....if i turn on both fans....the Temp goes to 150* and the stat opens and closes.......then after a while stabilizes......I have tha IAII block (bigger cooling passages/siamese cylinder...an E-brock pump, 2000 x 2 =4000 cfm of fan, and a 1.5 inch 2 row aluminum radiator....Couldn't beleive it! Eric:cheers


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## Instg8ter (Sep 28, 2010)

just did all of the normal stuff from the posts on here on mine, i did have the larger clutch fan and when i got the 18" shroud it would not fit so i trimmed off just enough of the fan tips to clear it with 1/8" gap. I then shimmed it to be half covering the blade and did the usual water pump mod. Other than that just a champion 3 row alum. radiator. Will post vid of the new set-up when i get it fine tuned on wed., have to rejet the 750 up as its starving for gas....<grin>. gonna break the motor in on the 750 while a friend machines the water neck down for the dual quads....then she will be able to eat.


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## Eric Animal (Oct 28, 2007)

Brian, Sounds good!......just to be safe.....can you verify an accurate temp gauge....


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## Instg8ter (Sep 28, 2010)

will do that with heat meter E, on my list of things to get today. man thats some tricky linkage on your carbs, i may have to have a waterneck fabbed if this one won't machine down enough (always something).


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## Eric Animal (Oct 28, 2007)

Not familiar with your set up....can you mill a little off the manifold........there are other options also....


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## Eric Animal (Oct 28, 2007)

The carb linkage is a bit tricky.....and that was before we put the TPS on the rear carb!!!!!.....E :willy:


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## Instg8ter (Sep 28, 2010)

E i am using dual holley 600's and the waterneck hits the power valve cover bolts on the bottom of the front carb, need to find a low profile one or have enough milled off the bottom of a 90 degree one to clear (gonna be close with not much flange thickness left). Verified the temp at 165, got the timing dialed in and carb adjusted, idled for 20 minutes never pushing over 165 until i shut it down, gonna get the hood back on and see if i get a rise to 175-180, if not i will swap to the 185 stat. new roller cam set-up has a nice lope at idle and pulls hard up to 4000 (as high as i have taken it so far). still have to tweak the trans to get the shift to hit a little harder but its getting there. Have to get it to the shop and have the front end alligned and electric place to track my brake light problem and it should be rarin to go for the Dream Cruise on the 18th.


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## Eric Animal (Oct 28, 2007)

Can you send a pic?


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## porkandbeans (Jul 24, 2012)

As a typical warm runner, you've got me jealous. 
Out of curiosity, what happens when running a little too cool? At 160*, or even 150*, will it cause damage?


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## geeteeohguy (Feb 2, 2008)

The engine is not as thermally efficient, it won't atomize and burn the fuel as well, (like a partially warmed up/cold engine), the choke may not open fully, causing rich running, and moisture/condensation in the crankcase won't burn off as well, which could result it corrosion damage to the bearings, etc. 160 is not really an issue, less than that is. Porkandbeans, being in the Inland Empire, I'm sure you know about heat....I'm in Fresno, and a good cooling system is mandatory for these old cars to live. Going to be 108 today, and 109-110 tomorrow....


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## porkandbeans (Jul 24, 2012)

^ good info to know - thanks!
My GTO won't be coming out of the garage in high heat. (Partly because I'm too lazy to sweat too much trying to shoehorn her out of the garage in such heat. haha)
My cooling concern is mostly for my Dodge Ram with an aggressive lift. It doesn't cool well since the lift and would then regularly run 205*-220*+. I dropped the thermostat and now it won't go above 165*. Efficiency is of some concern, but I'm more concerned of unnecessary and excessive wear on the engine. I love the cool running, but sure don't want to cause other problems.


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## 68greengoat (Sep 15, 2005)

The lift itself shouldn't have anything to do with cooling. In fact , since it's up higher you probably have better air circulation. What may be causing the higher temps, I'm assuming, is you have larger tires and probably not geared correctly so the engine is working harder. I'm running 200 - 205 with a new hemi.

BTW, you really shouldn't hijack this thread. You should start your own.... That is, if you are looking for suggestions for your truck...


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## Instg8ter (Sep 28, 2010)

Well to my surprise throwing the hood back on did not raise the temp a bit so i assume my cooling system is operating efficiently, time to swap out the stat.


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## porkandbeans (Jul 24, 2012)

68greengoat said:


> . . . BTW, you really shouldn't hijack this thread. You should start your own.... That is, if you are looking for suggestions for your truck...


Oops, didn't mean to thread jack. I was merely joining in on the discussion of how cool is too cool and the direct effects on the engine. 
My bad if it came across wrong.
OP: A thermostat change should work. It worked for me.


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## Instg8ter (Sep 28, 2010)

no problem P & B


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## 68greengoat (Sep 15, 2005)

porkandbeans said:


> Oops, didn't mean to thread jack. I was merely joining in on the discussion of how cool is too cool and the direct effects on the engine.
> My bad if it came across wrong.
> OP: A thermostat change should work. It worked for me.


Yeah, that's why I put the last line in my post after I had already submitted it after rereading your reply. I figured I misread it. My bad...............


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## Instg8ter (Sep 28, 2010)

ok dropped the new stat in...WOW what a difference, took care of my rich condition, pulled it up smooth to 3500 and she was just starting to breath and wanted to GO and stat stayed pegged at 180. With the 2:56 gear i dont think 120 would be out of the question. This car, now that its tightened up drives and rides better than any of my "New" cars, man what a pleasure. Had a guy in a Saleen Mustang stop dead in the middle of the street at a light to give me a thumbs up and a "Beautiful car" when i was leaving the station for the alignment. Now i cant wait to get the 12 bolt 3:55 and dual quads in to make her a bit quicker..... ....gotta love torque


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## Eric Animal (Oct 28, 2007)

The 3.55 rear will run great in your car....I had a set of 3.55s in a 66 GTO with a 4 speed years ago......could lay out some burnout!!!! arty:


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## Instg8ter (Sep 28, 2010)

Well the cooling system got the test yesterday, stuck in bumper to bumper stop and go for over an hour at the cruise on my way out and never topped 185-190. Over all the whole car was reliable and trustworthy...only problem all day was my Amp overheating and shutting off to cool down.


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## Eric Animal (Oct 28, 2007)

maybe the amp needs a little fan! :cheers


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## Instg8ter (Sep 28, 2010)

Or i need to turn my Rock and Roll down...arty:arty:arty:...:rofl:...


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## jetstang (Nov 5, 2008)

My second car was a 66 Tempest, 455, with granny gear. I had the speedo back around on zero, I sad 150 MPH! Then I had to stop with 4 wheel non cooled drums, scary episode. I swapped in a 70 GTO 3.55 gear and top end maxed out at 105 at 5000 rpms. Honestly, if you aren't racing it, just throw a posi in the highway gear and have a cool smoke show car. Or gear and Overdrive and keep some MPG..


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