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79FORMULA400
Buffalo

USA
75 Posts

Posted - 02 Oct 2016 :  11:00:18 PM  Show Profile  Reply with Quote
Ok guys, I need all hands on deck for this question... It has me stumped!
A little backstory.
I bought the car 2 years ago, drove for 6 months with a bone stock 1973 400 long block. Engine temps never exceeded 190 degrees even on the hottest day sitting in traffic. Car would typically run 175 cruising and 185 in traffic. This was with a 3500 stall converter that was way too big for the car and caused excess heat. Car came with a 26" Jegs 3 core aluminum radiator and 15" electric fan. Also had aftermarket flex fan, no fan shroud.
Fast forward to July of 2015. I installed a Summit 2801 camshaft and lifters. Put it all back together with the same water pump and divider plate. Car runs 180 degrees just driving down the road. The SECOND you get below 25mph or stop the overheating begins. It will hit 200 before you even know whats happened. At that point you have about 1 min to get the car off the road before it dies from the fuel boiling. I drove the car this way to school for 10 months or so. It was perfectly fine because my commute was all back roads and the car would hit 195 on the dot as I was pulling in the parking lot. Now I have a super T10 manual. I decided the other day I want to revamp and figure out what is wrong with the cooling system so I can go into town if I need to.

SO I drained the coolant and it looked fine. No dirt or debris. Pulled thermostat and found out it was hung halfway open! No wonder the car took forever to warm up! I installed a new 160 degree thermostat and re-filled the coolant. Same problem, car just warms up faster now. So I bought a new water pump and gaskets. Upon inspection of the old water pump I found out the divider plate had 1/4 inch of clearance to the impeller! I figured this had to be my problem all along. I set the clearance on the brand new NAPA pump (cast vanes not the stamped one) to .030 and installed new rubber gaskets that the divider plate seals to inside the timing cover. Cleaned all that stuff up while it was apart. Put the new water pump on and it overheats JUST AS BAD AS IT DID BEFORE. So bought a 10 inch fan to go next to my 15 inch electric fan. In total both fans flow around 2200 CFM of air. They make some serious suction through the radiator and I figured my problems would be solved... NOPE. Car STILL OVERHEATS. I can literally feel the hot air being forced through the radiator and out of the wheel wells. I ditched the regular flex fan when I installed the 2 electrics. I used an lazer thermometer on different places on the radiator and saw around 140-150 degrees at any given place. The cylinder heads/block and thermostat housing were reading around 175-185 degrees. I let the car cool 3 times and added coolant as it warmed up to ensure all the air was out of the system. Their is no coolant in the oil or any smoke of any sorts from the exhaust. I am at a total loss with what is going on here... I hope someone can help because its 65 degrees outside and my car still overheats. I just want to be able to drive it again...

1979 Formula 400 WS6, 1973 400 engine 4X Heads. Summit 2801 Cam, 8AN Fuel System,Edelbrock Performer MSD Dist, 6AL-2 Holley 750 Double Pumper,Super T-10, McLeod Super Street Pro, LSD Rear.

cortcomp
Coyote

USA
5338 Posts

Posted - 03 Oct 2016 :  09:46:25 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
What is your initial timing? I broke in my one 455 at like 10-12ish or so. Ran like 210-215 regardless of if it was fall or summer 110 degrees and idling, or cruising or whatever. Set the timing up around 15, amazingly the car ran 195-200 TOPS.

Also, other than the fuel boiling issues (which is weird because i've COOKED some carbed cars in my youth and they didn't stall from overheating the fuel), are you sure your gauge is accurate? On the last couple setups i paid attention to these things, the heads and intake temp matched what the temp gauge in the car said (newer gauge and matched sender.)
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 03 Oct 2016 :  11:00:56 AM  Show Profile  Reply with Quote
Read this and the follow up posts.

http://psp.aquacomp.net/topic.asp?TOPIC_ID=7410&SearchTerms=Cooling

Sounds like you took care of the divider. Personally I think electric fans are over rated and flex fans are total junk. Timing could be part of the issue also. A smaller pulley with a new clutch and a large 7 blade factory fan with no gaps between the shroud and the radiator, fan 50 % in and 50 % out...

Good luck.
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79FORMULA400
Buffalo

USA
75 Posts

Posted - 03 Oct 2016 :  11:04:35 AM  Show Profile  Reply with Quote
The timing on this car always seems to "self adjust." Before I left Ohio I set it at 18 degrees initial. I threw a light on yesterday when we were trying to go through all options and it was at 10 degrees! I wonder if that is my problem? I didn't even check to see if the distributor hold down had loosened up but I bet that is what happened. The really strange thing about this engine is when you are setting the timing initially, the mark likes to "jump" around. Like yesterday when I was checking it it would be exactly 10 degrees BTDC for a few seconds then the mark would "jump" a few degrees upwards towards the drivers side of the engine.
The other odd thing is everyone says that a vacuum advance distributor would help lower temps... Not the case for this mystery engine. I pulled the vacuum advance distributor (which was working 100% like it should have been) and installed the pro-billet style small cap distributor. I noticed ZERO change in the overheating. It was just the same with the pro billet.

I know the cause of the fuel boiling. When I installed my new fuel system I used an electric pump on the passenger side frame rail that ran up into the engine bay on the passenger side and went over to the carb. Now that I went back to an edelbrock mechanical fuel pump I temporarily routed the lines up and over the back of the bellhousing, behind the booster, and down to the pump on the drivers side of the engine. It is getting a ton of excess heat from the back of the cylinder heads before it even reaches the pump. Not only that, I checked the temp of the base of the intake manifold right where the carb sits... 180 degrees! That is heating the carb up quite a bit (along with the chrome air cleaner). All three of those things contribute to the fuel boiling. That has to be killing power. I remember we were taught for every 10 degrees you lower intake temps, you gain X amount of horsepower (Ill have to find the exact number). I need to re route the -8AN line down the drivers frame rail and that along with maybe cutting the coolant crossover should help lower intake temps and keep the fuel from boiling.

1979 Formula 400 WS6, 1973 400 engine 4X Heads. Summit 2801 Cam, 8AN Fuel System,Edelbrock Performer MSD Dist, 6AL-2 Holley 750 Double Pumper,Super T-10, McLeod Super Street Pro, LSD Rear.
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Blued and Painted
Chief PONTIAC

USA
3409 Posts

Posted - 03 Oct 2016 :  11:12:01 AM  Show Profile  Reply with Quote
240 is hot. 210 is not even boiling. Gm used a 238 degree fan switch in the 90's and 2K's.

double check temp sender and gauge.
Install correct shroud, fan, and HD fan clutch.
Late ignition timing will increase heat load.

Correct fuel peculation/flooding.
Is the correct 1/4 inch thick gasket under the q-jet?
Mixture screws adjusted to rich.
Is the choke completely unloading?
Is the exhaust heat riser opening if so equipped?
Check fuel pressure. should be around 5 1/2 psi. There are reports of replacement Airtec mechanical fuel pumps going as high as 7.5 psi
Is the float level to high or sinking/heavy float?
Metal fuel line touching something hot.



Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 03 Oct 2016 11:24:27 AM
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79FORMULA400
Buffalo

USA
75 Posts

Posted - 03 Oct 2016 :  11:40:11 AM  Show Profile  Reply with Quote
quote:
Originally posted by Blued and Painted

240 is hot. 210 is not even boiling. Gm used a 238 degree fan switch in the 90's and 2K's.

double check temp sender and gauge.
Install correct shroud, fan, and HD fan clutch.
Late ignition timing will increase heat load.

Correct fuel peculation/flooding.
Is the correct 1/4 inch thick gasket under the q-jet?
Mixture screws adjusted to rich.
Is the choke completely unloading?
Is the exhaust heat riser opening if so equipped?
Check fuel pressure. should be around 5 1/2 psi. There are reports of replacement Airtec mechanical fuel pumps going as high as 7.5 psi
Is the float level to high or sinking/heavy float?
Metal fuel line touching something hot.





We installed 2 aftermarket gauges (ones a year old the other is brand new) both in the intake manifold on either side of the thermostat. It looks like the fan shroud is the next place to go with this. Would putting a shroud around the radiator direct the flow of the electric fans better? Maybe run the fans and the 7 blade mechanical fan? I have a 750 Holley. Brand new gasket under that and the 1 inch spacer.
210 seems too hot. Under hood temps are HOT! at that range. That has to kill power just based on the fact of intake temps over running an engine at 175-185 degrees.
I have an AFR gauge in the car. Car runs about 13.5-13.8 AFR at idle and 12.2-12.5 at WOT. As far as running goes the car is exceptional for a 8.0:1 compression engine. It will leave patch all the live long day and pulls really well. Choke is completely open. No heat riser equipped. Fuel pressure is a steady 5.5-6lbs. I know how to fix the fuel boiling issue, that will only take me a few hours to fix. The engine overheating is where im stumped. I will try setting up the timing today and see if that helps.

1979 Formula 400 WS6, 1973 400 engine 4X Heads. Summit 2801 Cam, 8AN Fuel System,Edelbrock Performer MSD Dist, 6AL-2 Holley 750 Double Pumper,Super T-10, McLeod Super Street Pro, LSD Rear.
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cortcomp
Coyote

USA
5338 Posts

Posted - 03 Oct 2016 :  11:43:20 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I would definitely do that timing and test drive, easy and free fix if so. Also an 8.0 engine with pistons down in the hole can just generate way more heat than a higher compression motor with better quench because it's inherently less efficient.
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79FORMULA400
Buffalo

USA
75 Posts

Posted - 03 Oct 2016 :  11:43:26 AM  Show Profile  Reply with Quote
quote:
Originally posted by Brian R

Read this and the follow up posts.

http://psp.aquacomp.net/topic.asp?TOPIC_ID=7410&SearchTerms=Cooling

Sounds like you took care of the divider. Personally I think electric fans are over rated and flex fans are total junk. Timing could be part of the issue also. A smaller pulley with a new clutch and a large 7 blade factory fan with no gaps between the shroud and the radiator, fan 50 % in and 50 % out...

Good luck.




My buddy was having the same problem with his Small block 350 S10 as I am having. Tried running the biggest aftermarket aluminum rad he could fit with a mechanical fan. Went back to a stock replacement 4.3 V6 radiator with a 14" and 12" fan setup side by side just like mine. Before it would hit 210-220 in town. You can let it sit and idle for 20min and it wont go over 170. Even beating on the thing it wont get over 190. If nothing else fixes it I will go for the factory fan and fan shroud.

1979 Formula 400 WS6, 1973 400 engine 4X Heads. Summit 2801 Cam, 8AN Fuel System,Edelbrock Performer MSD Dist, 6AL-2 Holley 750 Double Pumper,Super T-10, McLeod Super Street Pro, LSD Rear.
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79FORMULA400
Buffalo

USA
75 Posts

Posted - 03 Oct 2016 :  11:46:38 AM  Show Profile  Reply with Quote
quote:
Originally posted by cortcomp

I would definitely do that timing and test drive, easy and free fix if so. Also an 8.0 engine with pistons down in the hole can just generate way more heat than a higher compression motor with better quench because it's inherently less efficient.



Exactly. Its a bone stock 1973 short block with what I assume are pistons .020 in the hole. I am planning on 9.5-9.8:1 compression very soon with a bigger camshaft (As you saw in my other thread). I want to make sure my cooling system running at 100% so I don't rattle the upcoming combo apart with detonation.

1979 Formula 400 WS6, 1973 400 engine 4X Heads. Summit 2801 Cam, 8AN Fuel System,Edelbrock Performer MSD Dist, 6AL-2 Holley 750 Double Pumper,Super T-10, McLeod Super Street Pro, LSD Rear.
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79FORMULA400
Buffalo

USA
75 Posts

Posted - 04 Oct 2016 :  02:45:10 AM  Show Profile  Reply with Quote
quote:
Originally posted by cortcomp

What is your initial timing? I broke in my one 455 at like 10-12ish or so. Ran like 210-215 regardless of if it was fall or summer 110 degrees and idling, or cruising or whatever. Set the timing up around 15, amazingly the car ran 195-200 TOPS.

Also, other than the fuel boiling issues (which is weird because i've COOKED some carbed cars in my youth and they didn't stall from overheating the fuel), are you sure your gauge is accurate? On the last couple setups i paid attention to these things, the heads and intake temp matched what the temp gauge in the car said (newer gauge and matched sender.)



Thank you sir for the solid advice here! Sure enough it was idling around at 10 degrees of advance. I upped it to 17 degrees and let it run for 15 minutes straight. Didn't get above 174 degrees. I haven't had a chance to really drive it in stop and go traffic but the issue seems to be totally resolved. Now I can finally drive my car again.

1979 Formula 400 WS6, 1973 400 engine 4X Heads. Summit 2801 Cam, 8AN Fuel System,Edelbrock Performer MSD Dist, 6AL-2 Holley 750 Double Pumper,Super T-10, McLeod Super Street Pro, LSD Rear.
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Blued and Painted
Chief PONTIAC

USA
3409 Posts

Posted - 04 Oct 2016 :  11:52:19 AM  Show Profile  Reply with Quote
Electric fans don't work well when mounted inside the factory shroud. Air flow seems to bottle neck when stopped at idle, then restricts flow at high way speeds. I've tried it. Once a hi heat/power load is reached the belt driven fan becomes more efficient than taxing the charging system with multiple electric fans. It comes down to cfm over heat load.
Many of the aftermarket flex fans are aimed at the small block chevy market. They wont pull enough air to cool an engine that is physically bigger with 25% more cid.
Dyno tests show an insignificant power loss when a factory type clutch fan is used.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 04 Oct 2016 11:56:16 AM
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Blued and Painted
Chief PONTIAC

USA
3409 Posts

Posted - 04 Oct 2016 :  12:02:40 PM  Show Profile  Reply with Quote
On a side note, you can't make good tea or coffee with water at 210 degrees.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 04 Oct 2016 12:06:27 PM
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