[pyjeep]

I have a 350 SB GM crate engine in a 63 Impala SS with stock radiator which is relatively new. The cam is one notch over stock, with DEI ignition and Holley 4B Avenger. Temperature gauge indicates 205-220 when warm and holds steady in the lower part of the range with higher temperatures only upon long idling, and thermometer in radiator cap indicates 160-170. Although it has never overheated or lost coolant, those temperatures seem warm to me. But I'm not an expert. Some possibilities come to mind ... radiator inadequate, radiator fouled, leaking head gasket, improper fan shroud (doesn't cover about 1" of the blade depth)?

Any thoughts on my quandry would be appreciated.

Phil Young

[bigbadbowtie]

Retarded timing can also cause over heating issues. 220 is pretty warm.
Are you sure your gauge is correct? Temp sender good? What is your timing set at?

[DoubleVision]

What source of vacuum is the vacuum advance connected to? full time manifold vacuum, or off idle ported vacuum? it should be connected to a full time manifold source. What temp thermostat are you using? Does the radiator have a overflow bung with a hose leading to a overflow can? If so are you using a pressure vent radiator cap? What kind of fan? Have you pulled a plug to see if it`s running too lean?

[Not A T 25]

Originally Posted by pyjeep

I have a 350 SB GM crate engine in a 63 Impala SS with stock radiator which is relatively new. The cam is one notch over stock, with DEI ignition and Holley 4B Avenger. Temperature gauge indicates 205-220 when warm and holds steady in the lower part of the range with higher temperatures only upon long idling, and thermometer in radiator cap indicates 160-170. Although it has never overheated or lost coolant, those temperatures seem warm to me. But I'm not an expert. Some possibilities come to mind ... radiator inadequate, radiator fouled, leaking head gasket, improper fan shroud (doesn't cover about 1" of the blade depth)?

Any thoughts on my quandry would be appreciated.

Phil Young

What are you running for a thermostat and what are you using for coolant? Hotter running motor makes more horse power but equals shorter engine life. What is the ambient temperature when you are seeing the temp?

[tomthecomic]

I thought I had a problem not to long ago. I replaced radiator(needed to) and was about to replace pump when I got a new (autometer) gauge. The old gauge was off 20. I have a radiator cap like yours when it is 180 the car gauge is 185. Also get a hi-flow thermostat.

[pyjeep]

Originally Posted by bigbadbowtie

Retarded timing can also cause over heating issues. 220 is pretty warm.
Are you sure your gauge is correct? Temp sender good? What is your timing set at?

Thanks. Timing is 6 BTDC. I suspected the sender or guage because there is a 50 degree difference between the guage and the thermometer in the radiator cap which has never indicated above 170. Also the top of the radiator feels just a little warmer than my Sequoia. Thanks for your help.

[pyjeep]

Originally Posted by Not A T 25

What are you running for a thermostat and what are you using for coolant? Hotter running motor makes more horse power but equals shorter engine life. What is the ambient temperature when you are seeing the temp?

My guess is 160 as that's what the radiator cap thermometer indicates when ambient temperature is in the low 80's. Coolant is mixture (unknown) of antifreeze and water. When ambient temperature is in low to mid 90's, the radiator cap temperature is about 170, and the temperature gauge about 225, versus 160 and 210 when the ambient temperature is in the low to mid 80's. That great a differential doesn't make sense to me. Another empiracle data point ... the top of the radiator feels "about" the same temperature as my Toyota Sequoia.

Thanks for your help.

[pyjeep]

Originally Posted by tomthecomic

I thought I had a problem not to long ago. I replaced radiator(needed to) and was about to replace pump when I got a new (autometer) gauge. The old gauge was off 20. I have a radiator cap like yours when it is 180 the car gauge is 185. Also get a hi-flow thermostat.

Thanks for the input. I also suspect the temperature gauge or sender. A 5 degree differential between the gauge and radiator cap thermometer makes much more sense to me than the 40-50 degrees I am seeing. Particularly since it has never boiled over, and the radiator top feels just a little warmer than the one in my Toyota Sequoia.

[Chevrolet4x4s]

is the sender or wire near the exhaust?
Shane

[pyjeep]

I'm new to this web site, and want to thank all who responded to my issue ... 350 SB seeming to run too warm. Your thoughts and recommendations have help enormously and given me many areas to explore. You've validated some of my thoughts and redirected me on others.

Now I'm going to spend some more time on this web site. It is truly remarkable for us gear heads.

Thanks again ... Phil Young (pyjeep@comcast.net)

[bigbadbowtie]

Phil... let us know how it turns out.

This site is one of the greatest....members range from 1st time hotrodders to 20+ year engine builders. I have yet to see an issue that could not be hashed out on here......most of the guys have been there, done that and have 1st hand experience.