1970 Chevrolet Nova overheating

Tiny
RSOTO89
  • MEMBER
  • 1970 CHEVROLET NOVA
  • V8
  • RWD
  • AUTOMATIC
I got a 1970 Nova with a 383 stroker and a Turbo 350 trans. Its overheats under a load after about 30 mins. I installed an all aluminum, 2 row radiator and a 180° thermostat. The radiator is solely for coolant: I have a separate cooler for the trans. I also have an electric and flex fan on it. There is no heater hoses/heater core attached to the cooling system. The car runs great but this overheating issue is driving me crazy. The only thing I can think to do is replace the water pump with a high flow all-aluminum one. Help please!
Wednesday, October 22nd, 2014 AT 7:46 PM

6 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Since the engine is modified, I have to ask what you have the timing set to. How many degrees BTDC is it set? Have you checked how far the advance is going when under a load?
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Thursday, October 23rd, 2014 AT 6:14 PM
Tiny
RSOTO89
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  • 3 POSTS
Initial timing is set @ 13° at idle. Then under a load of about 2500rpm it's at 45°. It's got a Mallory distributor with an HEI cap. Its also got stock ACDelco plugs with Taylor wires. I installed a mechanical coolant gauge and its calibrated and working fine. The hottest the engine will get is about 210-220.
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Friday, October 24th, 2014 AT 12:29 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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This is a tough one. Everything is basically new. The timing seem a little further advanced than I would expect, but not that far out of line. I assume you mean 13 BTDC. This is a stretch. Do me a favor and check to make sure the lower radiator hose isn't collapsing when the engine revs. It's been years since I've see this problem, but it did years ago.
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Friday, October 24th, 2014 AT 8:27 PM
Tiny
JACOBANDNICKOLAS
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You know, I just re read your last post. That temp isn't really out of line when the engine is under a load.
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Friday, October 24th, 2014 AT 8:28 PM
Tiny
RSOTO89
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The lower radiator hose has the wire inside it to take care of any collapsing problems. I was wondering if the "normal operating" temp for that kind of motor would differ from say a daily driver.
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Friday, October 24th, 2014 AT 9:43 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Yes, it could have an affect. A larger angle can, compression. All are factors. If it never goes above 220, I don't know that it is really a concern. As you are aware, factory t-stats fully open at 195. It isn't out of the ordinary for an OEM engine to run at 205.
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Saturday, October 25th, 2014 AT 8:30 PM

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