Using a 301 HEi in a 400 Pontiac

[BradZZ]

I have a 75 TA motor in a 81 GP which runs great til the summer heat. Ive got a 160 deg T/stat, Edelbrock intake and a Q-jet off a 78 4bbl 301 and I used a 301 HEI out of a 77 GP. The car orig had a 301 2bbl, and I used stuff I had on hand.
Until it get around 80 deg outside the car runs at 180 deg all the time. But above that! 240 was the worst I've seen setting in traffic on a 100 deg day with a/c runing, Taking grandbaby to Dr.
or would have turned off a/c!
IS there a different timing curve to the 301 and would this cause overheating?

[BradZZ]

I have a 75 TA motor in a 81 GP which runs great til the summer heat. Ive got a 160 deg T/stat, Edelbrock intake and a Q-jet off a 78 4bbl 301 and I used a 301 HEI out of a 77 GP. The car orig had a 301 2bbl, and I used stuff I had on hand.
Until it get around 80 deg outside the car runs at 180 deg all the time. But above that! 240 was the worst I've seen setting in traffic on a 100 deg day with a/c runing, Taking grandbaby to Dr.
or would have turned off a/c!
IS there a different timing curve to the 301 and would this cause overheating?

[pontiarrg]

just a guess but i bet the radiator cant handle the heat load of the bigger engine. maybe a 6 blade fan and lose the fanclutch will work but i am thinking bigger rade8tor. http://forums.performanceyears.com/groupee_common/emoticons/icon_rolleyes.gif

[David Jones]

What diameter is your fan. How many blades? Is there a fan shroud? Do you experience overheating on the highway or just in town? If your problem is in town you need more air flow through the radiator, assuming its in good shape. Also may want to try a 180 degree thermostat. Big Pontiacs need lots of air to stay cool. http://forums.performanceyears.com/groupee_common/emoticons/icon_smile.gif

http://kurtspontiac.homestead.com/DavidJones69GTO.html

[mike nixon]

I HAD / HAVE A 455 OLDS IN AN 81 AND HAD THE SAME PROBLEM. IT WAS AIRFLOW.

MAKE SURE THE A/C CONDENSOR IS CLEAN AND NOT RESTRICTING THE AIRFLOW.

PUT A TEMP ACTIVATED ELECTRIC FAN THAT COVERS AS MUCH SURFACE AREA AS POSSIBLE ON IT WITH A GOOD CLUTCH FAN AND A SHROUD THAT FITS IT.

IF YOU WANT TO GO TO A BIGGER RADIATOR THE 81-7 DIESEL RADIATOR HAS THE MOST CAPACITY AND IS A BOLT-IN.

I ALSO RAN AN OIL COOLER ON MINE AND TRUE DUAL EXHAUST.

IF IT OVERHEATS WHILE MOVING YOU HAVE A DIFFERENT PROBLEM.

MIKE

[Rick Lightfoot]

Water pump plate rotted, stamped steel water pump impeller, missing anti cavitation spring from lower hose.

http://kurtspontiac.homestead.com/files/77canam.jpg

[sviguy]

I consider Mr. Nixon expert in this field

can you hear me now? is this thing on? test 1 2 1 2

[428GTO70]

I cant remember but does a 301 distributor turn clockwise instead of counterclockwise? Seems I heard this somewhere before. Maybe it dont but if it did you would have to flip the advance cam and weights over in the distributor for it to advance properly in a pontiac 400.
Anyone else knowfor sure?

http://www.mensexpo.com.futuresite.register.com/db1/00024/mensexpo.com/_uimages/tigeranm.gif
GR-RRR!

[BradZZ]

Well Sorry about slow return.
The 301 I beleive turns the same way it does work in the 400. I have a new 3 core rad (the biggest I could find for a G-body at my price) I guess from your reponses you feel the cooling systems the culprit. I tend to agree at speed it cools fine But at idle in traffic it has the heat problem. I'm thinking of getting a dual elec fan this spring.
As a question: what is meant by distributer curve anyway? Is it just the springs or the counter weights also that determine the advance in the distributer?
thanks
Brad in Louisville

[mike nixon]

the distributor curve is the amount and how fast the distributor advances. both mechanical and vacuum advances affect this.

the 267 / 301 rotation is the same as the 350 - 455's. the 326 was the oddball that ran backwards.[ the distributor sat on the other side of the cam]

from what i remember the 301 used the same curve as the comparable 350 / 400.

you can buy a recurve kit from a speed shop and change the rate of advance that the distributor has.

make sure the vac advance is hooked to ported vacuum.

you can also buy a adjustable vacuum advance unit and change the amount of total timing the engine gets.

try advancing the base timing a couple of degrees and see if that helps. don't go too far or you'll run into a detonation problem.

retarded timing will cause an engine to run hot.

how much compression does your engine have? if it's over 10:1 the car will run warm.

if the above doesn't help you'll need to do something about the cooling system.

seal the radiator to the core support so all of the air entering the engine compartment has to go thru the radiator.

run a good 7 blade clutch fan that fits the shroud. a diesel car will be a good donor if you don't already have one. the fan blades should be in the shroud about 1/2 way.

don't use a fan from a serpetine belt car, most of the turn the opposite direction from yours.

electric fans may help, if you go this route wire them to turn on automatically with a 180 switch and a relay.

if the above doesn't help you 'll need to upgrade the cooling system to handle the load.

you can sell your current radiator to someone with a small block malibu or cutlass.



mike

[BradZZ]

Thanks Mike, You've brought up a few things I havent checked : ported vac on carb for distributer, sealing around rad. The car doesnt have a problem til its over 85 in summer. If not an elec fan. I may try a fixed fan instead of the clutch (7 blade) fan I'm using , for the summer only. I think its a matter of not getting the air flow thru the rad since even on hot days theres no overheating if the cars moving at 35 mph or more.

[Steve Barcak]

*Pontiac 301 distributor turns clockwise?
*the 326 was the oddball that ran backwards.[ the distributor sat on the other side of the cam]

C’mon guys! I don’t know what your sources are for this , but you are mistaken. All real Pontiac distributors turn counterclockwise. All Real Pontiacs have the distributor on the same side of the cam. I have every production Real Pontiac engine from 1955-81 in my wrecking yard. Is there a book somewhere that gives that wrong info or ? Steve www.pontiacheaven.org (http://www.pontiacheaven.org)
“Real Pontiacs Only..............No Corporate nonsense!”

[mike nixon]

i'll have to do some digging to find the source of the 326 comment.i think but won't swear to it the info came from an old [70's] motor manual.

it's been years since i've been into one.

it was a 67 lemans engine a friends brother owned and for some reason i remember the distributor rotation being revese of the 400 i was driving at the time.

if i've passed some wrong info on i appologize.

mike