1970 novs ss overheating

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i have been having problem after problem with my nova it has a 355 all aftermarket engine. just had the heads rebuilt and all gaskets replaces, still has a few leaks but nothing to awful. i am having a problem with overheating and have tried a few things the first time i started it after all the gaskets were replaced the intake gasket wasnt sealed right and was bubbling out coolant so i replaced it thinking it would fix it but it didnt. i also noticed the brakes seem to start holding when it warms up but that probly just because of the heat problem. the car can sit in the parking lot and idle all day and work just fine but if i let it get to the temp is supposed to be at and take a small lap it jumps to 200 when i stop it cools down. anyone have any ideas, the timing is a bit off starts good but when i turn it off warmed up it tries to roll over a few more times it was off a bit before the rebuild also but never oberheated like this.

posted by  rage141414

Uh, I think u shouldn't mess around with it anymore. You're obviously not good enuff and ur messing it up. Heed my advice, take it to a shop and have them re-fix everything you've fixed, you'll thank me later when ur engine actually lasts. :clap:

posted by  Carcass

it has been mostly done by a mechanic or overwatched by one, i only did the gasket part, i like to see what the problem is before i take it to a mechanic so i dont get taken to the cleaners.

posted by  rage141414

This sounds kind of obvious; but sometimes the obvious is easily overlooked.
How long was it sitting before or during the rebuild? Have you checked the thermostat? I own a "73" and although it wasn't sitting I hadn't cleaned out the coolant system for a while and it was having the same issues. It turned out the thermostat was rusted shut or open or whatever. Anyway I swapped it out and my problem was solved. Hope I helped. Good luck if I didn't.

Take care of that girl. If you don't you will regret it. Somebody tried to steal mine and I caught them but to do it I had to spin it out with my Jeep. I ended up smashing the rear quarter panel (no creases) and totaled the drivers door. Now I am debating selling her.


posted by  jeepmaniii

Either the thermostat, the radiator or the water pump... check the therm and then flush the rad and then do a pressure test.

posted by  srober32

make sure the dope at the parts shop didn't sell you a reverse rotation water pump, or make sure you screwy drive belts aren't running it backwards.

posted by  carls47807

you didn't mention what original engine the BossaNova had.

If it had a six, change the 2 row Rad core for a 4 row core.

Aslo be very sure the thermostat isn't in upside down. it will run cool at idle do to the bypass feature, but it will heat very quickly....

Reading through you email I noticed the engine is "dieseling" This is either heat related or timing related. Have you put a light on it to check the timing?
Usually the timing is too high.

I couldn't really get if it has had the problem all along or if it just started.

Hope this helps.

posted by  oldtimebuilder

If it has a clutch fan check the clutch mechanism.

posted by  mcapony

i saw a 6 cylinder bmw that had the timing off enough that the exhaust manifold was glowing cherry red at night.if your timing is out enough that your valves are hot enough to burn fuel after you shut it off,the timing is way off. put a bigger fan,water pump,radiator,something obvious here.personally i would put in a solid state ignition if you do not already have it .

posted by  the lobster

still leaks a little? why?...there are 4 main reasons for overheating

- Insufficient Air Flow
- Insufficient Coolant Flow
- Coolant Leaks
- Insufficient Cooling Capacity

so... start there, and if timing is retarded this produces higher cylinder temperatures, resulting in increased heat removal requirements.

id say fix the leaks first, seems too obvious eh?

posted by  BanffAutoSpa_ap

If the temp goes up to 200 and not above, I wouldn't worry too much about that but I agree with Banff, fix the leaks and adjust the timing to specs. Imagine if you will, a young man with a sweet ass ride, a '70 Nova let's say, says "yeah, she's got a newly rebuilt 355 witha 750 double pumper and dualies." His buddy says "cool, pop the hood!" He does and here is this gleaming, shiny, fluid covered motor. Then he has to find a new friend 'cause the old one thinks he's a liar. May not happen but a leaking engine does not look good or run good.

posted by  srober32

As for the brakes, if you have four wheel drums or just drums in the rear they are probably over tightened and as they heat up they tend to grab and lock up more. If you cannot pull the drums off (assuming they are drums and they do not have a rust ridge) fairly easily, they are over tight.

posted by  srober32

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