1970 Chevrolet Nova overheating

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!

6 Replies

JACOBANDNICKOLAS

MECHANIC
109,645 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?

Was this

answer

helpful?

Yes

Thursday, October 23rd, 2014 AT 6:14 PM

RSOTO89

MEMBER
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.

SPONSORED LINKS

Was this

answer

helpful?

Yes

Friday, October 24th, 2014 AT 12:29 PM

JACOBANDNICKOLAS

MECHANIC
109,645 POSTS

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.

Was this

answer

helpful?

Yes

Friday, October 24th, 2014 AT 8:27 PM

JACOBANDNICKOLAS

MECHANIC
109,645 POSTS

You know, I just re read your last post. That temp isn't really out of line when the engine is under a load.

Was this

answer

helpful?

Yes

Friday, October 24th, 2014 AT 8:28 PM

RSOTO89

MEMBER
3 POSTS

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.