Fresh rebuilt 302, with AFR heads, long tube headers, blah, blah. We are using a NEW radiator from LMC truck for a "302 V8 F-150". New water pump, new hoses. New everything!

It's consistantly running at about 210 in town. On the road it gets down to about 185. And in slow traffic, got to 230 once.

It's also got a dual fan setup flowing a lot of air. The fans were about $450 and I can't imagine how to get any more air over the radiator than these fans do. Yes, they're shrouded too.

So, at 60 mph it will run in the 180's. But at parking lot speeds and slower roads, it runs in the 210's.

That tells me there isn't enough air flow at low speeds. BUT, there can't be any more air flow than what we've got. I've also got them wired to run full time.

Do you'll know if a bigger radiator capacity would do the trick? This one is 2" thick, the same as I use in my LS1 RX-7 swaps, that of course larger engines than this thing.

 

Did you bore out the cylinders? The 302 in my Capri behaves the same way as yours. It has a .040" overbore. I have tried 2 different radiators, 2 water pumps, , 2 water pump pulleys, 3 t-stats, added a shroud to the flex fan and put 2 12" electric fans in front and all I have managed to do is slow down the heating process. I simply avoid driving the car during heavy traffic periods. I have heard some 302's have thinner cylinder walls than others and will run hotter when bored out. My 302 also had a small head gasket leak, it didn't blow any smoke but the plugs had coolant crud on them. Even after fixing that it was a little better but I still can't trust it. It runs at a steady 200* until you stop then slowly climbs. I will pull over and shut it down if it hits 230* though.

 

Actually, it is .030 over, now that you mention it. Hummm.

 

Mine is stock bore and stays at about 200* also.


Just drove 2 miles to walmart and when I got back home it was at 200

 

Man oh man. We still don't have the a/c running, or the supercharger. This could get interesting. It doesnt help that it's about 100 outside lately.

 

You are on the borderline, but it sounds like it's still driveable. I have found 230 is about the limit, since most of my cars with carbs will start running rough above that. I believe the fuel starts to boil in the carb above 230. A lot of factory fuel injected engines run that high and the electric fan switch is set at 230.

What I am curious about is how do you have your timing setup? Usually the factory had the initial set pretty low, the centrifugal set conservative, and lots of vacuum advance timing. Try this experiment. Disconnect the vacuum advance and plug it. Leave it out of the picture for the moment. Turn the dist to set the initial as high as you can go before it detonates on a hard pull and or will crank over easily after you shut it off for 2 or 3 minutes. I have run mine up around 14 degrees initial. Drive it around like this(with the vacuum advance still disconnected) and see if the heating problem is helped out. If it is, you might want to leave it like this, and then get an adjustable vacuum advance, and tune it so it will not detonate. You may find you can only run 4 or 5 degrees vacuum advance with the initial set high, but you will be amazed at the throttle response with it set this way, and it may help the cooling problem.

 

Franklin,

Being "LS1 powered" for so many years, I've been more into tuning with my laptop than anything else. This truck has really brought back a lot of memories for me of high-school (mid 80's) and my '70 Firebird Formula, and it's distributor cap type ignition.

As of today, we don't have a timing marker on the engine. I set the timing to "something" advanced before we ever cranked it. So much has happened since then, that well, I think it's never been addressed. Recently I was thinking about my "bird" and began to rememeber about the whole timing thing, and it's affects on the engine during driving.

Long story short, I think you're right, and I'll find out in a day or two and let you know what I discover. The truck is at my father-in-laws staying out of my way for a short bit. I've got a few RX-7's to get built and gone before I can get back on the truck.