Overheating 283ci

[Ernest C.]

I really need some help. I have a newly rebuilt 283ci 270 hp but with hydraulic lifters. The engine temp is over 200 degrees within the first 5 miles. Everything is new or rebuilt (waterpump), and I have already replaced the fan clutch with another new one. Both came from Paragon. I hate to think I have to change the waterpump but that might be the only thing left. Today I'm going to remove the thermostat, and try running without, but if you have any ideas I would appreciate it.
Thanks

[Joel T.]

Re: Overheating 283ci

Ernest;

Before you start taking stuff apart I would check some things... Check your timing to make sure it is correct... Check your heat riser valve (right side exhaust) to make sure it is opening and that there are no restrictions in your exhaust. I would also try and get an IR temperature meter to see what temp you are actually running at... If you have replaced the temp sensor keep in mind that the repros are not all that accurate. I have a Paragon repro in my 1963 which shows well above 200 degrees basically all the time... but actual testing shows it is really much cooler than that!

I'm sure that others will have some suggestions as well.

Good luck,

Joel

[Timothy B.]

Re: Overheating 283ci

Joel's advice is right on, find someone with a IR gun and get a second reading on the temperature before you take anything apart..

[Stuart F.]

Re: Overheating 283ci

I'm with Joel on this one. You need to check things out first before you start throwing parts at it.

You mentioned the thermostat; what rating is it and is it new? I would not remove it entirely as you may just exasperate the problem. You need a thermostat to control the coolant flow through the radiator. Without one, it will just pass through the radiator at a rapid rate which will not allow it to be cooled. You might just as well flush it through a tank for all the good it will do.

Also, don't forget that a newly rebuilt engine may run a little hot until things seat in some. We used to use the old rope rear main seals and stuff it in entirely. The engine was hard to get started the first time and needed a lot of throttle opening just to keep it running. Then, over a period of an hour or so, it loosened up and we had to keep backing off the idle speed. This is an extreme example, but with yours it could be the tolerances may be just a little tight.

One thing of question; you say it is a 270 hp with hydraulic lifters - was a new cam and lifters installed and, if so, are you certain the cam was properly degreed in and not a tooth off?

Actually, I probably shouldn't even mention that as at this point, you are dealing with only a 200* temp which is not all that significant with a newly rebuilt engine. And too, get the IR gun on it first to make sure where you are at, like Joel suggests.

Stu Fox

[Jim L.]

Re: Overheating 283ci

If your gauge is accurate and if the timing really is set properly, then the next thing you'd want to investigate is the air/fuel mixture. A lean mixture will dramatically heat up an engine.

Jim

[Ernest C.]

Re: Overheating 283ci

Thanks very much for the advice.
Just for further information, I have an IR thermometer, and it confirms the temperature readings, the thermostat is new, and is set fir 180 degrees.
I will check the air/fuel to see if that helps, and also put a lower degreed thermostat in today.
Thanks again

[Stuart F.]

Re: Overheating 283ci

That brings up a good point Jim; just how well is the engine running? Usually if it is too rich or too lean it will it will show in how it runs. Noting that he has now a hydraulic lifter engine, it's not too likely he's running a very wild cam and a mixture condition should easily be noticed.

Stu fox

[Jim L.]

Re: Overheating 283ci

the thermostat is new, and is set fir 180 degrees.
I will check the air/fuel to see if that helps, and also put a lower degreed thermostat in today.

Changing to a lower temperature thermostat is likely to be little more than a distraction. The thermostat determines the MINIMUM engine operating temperature, not the maximum. I wouldn't bother.

A brute force way of testing the air/fuel theory would be to jam the choke partially closed and go for a test drive. You won't know the actual air/fuel ratio but it'll definitely be richer. If the engine temps are lower, you are on the right track.

EDIT: Further thoughts..... what is your radiator? Is it an original Harrison radiator? If so, has it been cleaned out by a radiator shop? If it's not a Harrison (or a DeWitt repro), is it an aftermarket piece? Some of the after market radiators look small to me and I'd wonder about their heat rejection capacity.
Jim

[Ray C.]

Re: Overheating 283ci

After the completion of the rebuild on my 283-CI, 270-HP 1961 engine I had an overheating problem. I discovered that the original expansion tank had corrosion in the cap area. This prevented the system from pressurizing correctly. Replaced the expansion tank and cap and have not had a problem for the past 7 years. If all else fails run a pressure test.

Ray

[Ernest C.]

Re: Overheating 283ci

Thanks again.
The radiator is a new Dewitt, and the expansion and cap are also new from Paragon. The engine runs VERY well, and I am pleased with that. I did buy a rebuilt matching nember waterpump from Goat Hill, and I guess if all else fails I will have to pull the pump which I hate.

[Stuart F.]

Re: Overheating 283ci

I'd say if it is running good and not pushing much over 200* while cruising, leave it be for now. If it is exceeding 200, in other than normal expected circumstances like sitting in traffic on a hot day, then you may want to look into it further. Give it a little breakin time. If the temp bothers you, drop in the 160* thermostat. I have had a 160* in my L-76 63 since practically new because I didn't like to see needle climb much in traffic, and it has always seemed to run better with it. I broke it in during the heat of summer in the desert southwest with a 180* and it worried me to death. Same way I can't stand to see oil pressure bouncing at 15 lbs at idle in traffic.

Stu fox

[Stuart F.]

Re: Overheating 283ci

You should re-title your thread to "warm running 283". If it were overheating you'd know it specially if it was pushing coolant out.

I had a 58 290 hp fuelie in my first car - a 50 Chevy coupe, and I really did overheat it twice. It burst a hose once and lost a fan belt I believe the second time, but it was steaming! Funny thing, the engine ran better than ever after each incident. I use to joke that it probably collapsed the pistons a little or at any rate loosened up some tolerances cause it ran like a Banshee afterwards!

Stu Fox

[Bill C.]

Re: Overheating 283ci

What's your coolant mix ? A anti-freeze concentrat of more then 50% will lower the ability to cool also..........................Bill 20328

[Ernest C.]

Re: Overheating 283ci

This is to Ray Carney, after reading your comments regarding the overflow tank, I rembered that I had broken the one tube on the tank and tried to cold weld repair. I have now replaced the overflow tank, put in a new thermostat, and tomorrow will go for a ride.
Thanks to everyone with their suggestions.

[Jim T.]

Re: Overheating 283ci

The higher heat could also be from not having full time vacuum advance if your first five miles are driven in city tarffic combined with a newly rebuilt engine.