Runs awesome but alittle hotter than normal?

Had the car out today which was a beautiful day like 80 degrees no humidity,it runs excellent and power is awesome but i am alittle concerned why its running hotter than it was with the steel heads?was running in town stop and go at about 200-205 w/ the my traffic fan(electric fan)on at all times which i normally just switch on when i get stuck in traffic and the temp.starts to creep up,why would that be?could it be cause the Aluminum heads are new until they loosen up?is it normal for aluminum to run alittle hotter?


Thanks
o No:

 

George,

You may need to fatten up the primary circuits on the carb now..

If anything it should run cooler.. I had a report back from a guy out in southern Calf who just installed one of our STG 1 Alum motors, and he said that even with just a 3 core rad, on a hot summer day, a one hour cruise resulted in the engine temp never going over 180*.

His carb was a little on the "fat side" during the cruise test on the dyno, (typical for a 950 Holley) but I left it that way purposely.

It is my opinion that in most overheating situations with this motor, iron or alum heads, the A/F ratio of the carb during cruising is typically too lean, which can easily push a marginal cooling system "over the edge".

With an electric fan, I would expect you to have to run it all the time in stop and go traffic. I tend to shy away from the electic fans for street applications, preferring to use a particular combo of 7 blade fan, fan clutch, and shroud to deal with the heat. I have had excellent results in a number of cars with different motors, with this combo. A search of "fan clutch" on this site will detail that combo.

JW

 

Jim,what do you mean Fatten the the primary circuits on the carb?larger jets?or anything else?i mean i would think it should`ve run cooler but i dont know why its runninng hotter than normal?i have an 800 dp buy the way any helpis greatly appreciated.

Thanks

 

And how do i go about adjusting it the right way?what do u suggest?

 

what carb you running George?.. and what jets or jet/rod combo are you using?

JW

 

stock Holley 800 dp never been touched except the power valve and scuirters,never fooled with the jets.

Thanks Jim

 

go up 2 steps in the front, and see what happens..

JW

 

ok:TU:

 

I've always observed that cast iron engines that nornally run at 180 deg/F, and have had aluminum heads installed, run better when the water temps are lifted to 192/195 deg/F.

Even the all aluminum 215 and Rover stuff I do likes 192 de/F.

A friend has a '66 Chevelle, was all cast iron, went to a set of aluminum L88 heads with his tri-power, 4 speed, didn't wake up as it should have. I suggested he go to a 192 thermostat, the engine then came alive.

Heat rejection is a bit different with aluminum over cast iron. Chamber heat has to be maintained, water temps readjusted is one way to help. Of course, you won't see all this on a dyno, as engines follow very different paths than the same setup running in a vehicle.

 

What size radiator are you running? What degree t-stat are your running? You may want to pull the t-stat out and make sure its opening all the way. 205 is too hot for my taste in our cars.

Some debris from your head change could be lodged in the t-stat not allowing it to fully open at temp.

 

Griffin Al. radiator,i just changed the 160 thermostat when i did the head change to a new one,i know its too much and with the fan on???o No:

 

my 67 is doing the same thing

George,

i've been admiring your car on many diferent sites before i cam to this one. i also have a 67 gs skylark. i amd currently haveing the smae difficulties with my overheating as you are. as i stop and idle, my temp creeps up to about 205-210. i flush and filled the radiator thinking it was a clog, and i rplaced the water pump thinking the impeller was shot and not pumping enough water through. nothing is working. i do not thin it has anything to do the the aluminum heads personally, because i do not have aluminum heads and my engine does the same EXACT thing. My question to you is what size radiator do you have? How many blades do you have on your fan? have you cooked out your radiator? does the coolant start to boil when you shut off the car?

Sinclair

 

Thanks for the compliment on the car Sinclair,I have an aluminum radiator,but it wasnt running that hot with my steel heads,i used to turn the fan on only sometimes when i used to hit traffic,i havent taken the car out since so thats why i havent replied yet,i have a clutch fan 7 blade,160 thermostat,and the electric fan only for traffic,i will take it out this weekend and i`ll see how she`s running,what rad. are u using?if stock junk it,get alum. radiator.
Thanks

:TU:

 

thanks i appreciate it

thank you george for replying, i will deffinately look in too the aluminum radiator. and i will probaly step the fan up to a 7 blade and install a fan clutch. did you mess with yuor carb at all yet, and if so did it help?

i appreciate the help

sinclair

 

I changed the jets but i havent taken her out yet thats why i didnt relpy yet,will do it this weekend.

Thanks

 

ok. thank you. sorry bout the badgering of questions, but good luck with taking it out. let me know what deal is, hopefully it will work!

sinclair

 

no problem,will do.:TU:

 

how did it turn out?

did you try changing the A/F mixture yet? If so, did it work?

 

I did and i also changed the jets 2 #`s up,i havent driven it much when i took it out last weekend it was still running hotter than normal with the fan on,the next thing im thinking is maybe because the compression is higher now with these heads it may be running hotter?it only runs hotter in stop go driving,on the highway it looks to be ok,worst case scenario i`ll just throw on my dual Spal fans on and take the stock fan off.


Thanks

 

In my Skylark, I run dual 12" Permacool fans, and I rarely even need to use them. My setup is as follows: '68 430, Mild cam, Mild Head work, 800 Edelbrock, manifolds, and dual 2.25" exhaust. I use the stock 3 core rad, 94 octane and about 10.5:1 compression. with a 160 stat, it stays right at 160 in traffic, and at the light with the fans on, it climbs to 175, after about 15 minutes. I can stop for 2 or 3 minutes at a time with out the fan and have the temp climb upto 190, but it drops like a rock once I get moving. this is in 75-85 degree weather.

AS for Georges problem, I dislike Griffin Rads. back in the day when I had the 430 in my 85 T/A, I had the 31x19, with dual 1 1/4 cores. the motor would overheat like no other, it would climb right to 250. I blame some of the overheating on my heads, although that radiator was enormous, and just couldn't cut it. now the stock, smaller 3 core radiator works much better. Joe