Temperature issues

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TheGreatPumpkin
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Re: Temperature issues

Post by TheGreatPumpkin »

jsgarage wrote: Fri Oct 07, 2022 4:04 pm If you've actually tried all 3 pgs of suggestions and nothing has changed, a few more things to check:

1)- calibrate the temp gauge that has you worried. Or plug in a cheap replacement for a checkup. Generally, if the rad is not spitting water, its not overheating regardless of what the gauge says. To be sold in the U.S, any gauge must read to within +/- 2% of its scale at mid-range. "Precision" gauges must read closer than 2% to be legally sold. Bad electrical crimps or grounds are common- especially if you used teflon tape to seal a temp sender to the block. More than 1.0 wrap of the tape on pipe threads can insulate the sender and cause it to read poorly.

2)- electric fans are not linear with respect to air delivered vs voltage applied. A 1500 cfm 12v fan that only gets 10 volts will deliver about 50% of its rated air. Hot-wire your fan(s) directly to the battery and see if that noticably increases air movement. It's possible that a car's OEM wiring has developed poor connections somewhere in its loom. To solve my problem, I bought a cheap hand-held anemometer to actually find how much air was flowing. I found several areas in my car's grille where incoming air had found a way to avoid actually going thru the radiator.

3)- make very sure both sucker fan(s) actually suck air. Blowing air fwd from behind the rad with one sucker fan wired wrong will certainly cause overheating. A piece of paper held in the outflow (or in front of the rad) will tell you which way air is actually going without a gauge. Good luck.
Thanks for the tips. I upgraded the fans to the biggest ones from Spal that would fit, and that helped a bunch. Temps are really never above 200 now. Brand new harness, wired right, etc. Right now focusing on airflow issues with grille duct, chin spoiler, hood to rad support seal, etc, and I will report back. Temp sender is sealed with a bit of Hylomar, not tape, but I can see if I can remove it.

Bit hard to see, but i boxed in the area in front of the rad with 1/16" Lexan as tight as possible to the hood and grille. Haven't gotten a chance to drive it, got other projects to restore and sell...
PXL_20221003_003644510.jpg
PXL_20221003_003653688.jpg
PXL_20221003_003706291.jpg
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TheGreatPumpkin
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Re: Temperature issues

Post by TheGreatPumpkin »

TMP Carbs wrote: Fri Oct 28, 2022 2:51 pm
TheGreatPumpkin wrote: Fri Oct 07, 2022 4:11 pm
jsgarage wrote: Fri Oct 07, 2022 4:04 pm If you've actually tried all 3 pgs of suggestions and nothing has changed, a few more things to check:

1)- calibrate the temp gauge that has you worried. Or plug in a cheap replacement for a checkup. Generally, if the rad is not spitting water, its not overheating regardless of what the gauge says. To be sold in the U.S, any gauge must read to within +/- 2% of its scale at mid-range. "Precision" gauges must read closer than 2% to be legally sold. Bad electrical crimps or grounds are common- especially if you used teflon tape to seal a temp sender to the block. More than 1.0 wrap of the tape on pipe threads can insulate the sender and cause it to read poorly.

2)- electric fans are not linear with respect to air delivered vs voltage applied. A 1500 cfm 12v fan that only gets 10 volts will deliver about 50% of its rated air. Hot-wire your fan(s) directly to the battery and see if that noticably increases air movement. It's possible that a car's OEM wiring has developed poor connections somewhere in its loom. To solve my problem, I bought a cheap hand-held anemometer to actually find how much air was flowing. I found several areas in my car's grille where incoming air had found a way to avoid actually going thru the radiator.

3)- make very sure both sucker fan(s) actually suck air. Blowing air fwd from behind the rad with one sucker fan wired wrong will certainly cause overheating. A piece of paper held in the outflow (or in front of the rad) will tell you which way air is actually going without a gauge. Good luck.
Thanks for the tips. I upgraded the fans to the biggest ones from Spal that would fit, and that helped a bunch. Temps are really never above 200 now. Brand new harness, wired right, etc. Right now focusing on airflow issues with grille duct, chin spoiler, hood to rad support seal, etc, and I will report back. Temp sender is sealed with a bit of Hylomar, not tape, but I can see if I can remove it.

Bit hard to see, but i boxed in the area in front of the rad with 1/16" Lexan as tight as possible to the hood and grille. Haven't gotten a chance to drive it, got other projects to restore and sell...

PXL_20221003_003644510.jpg
PXL_20221003_003653688.jpg
PXL_20221003_003706291.jpg
There is more than enough air flow there without boxing anything or the chin spoiler. Does this have headers? I haven’t read the pages of suggestions, but a radiator hose sucking shut will cause heating
I tend to agree with you but the evidence says otherwise. Yes, coated headers. Lower hose has spring in it.
TheGreatPumpkin
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Re: Temperature issues

Post by TheGreatPumpkin »

TMP Carbs wrote: Fri Oct 28, 2022 3:44 pm
TheGreatPumpkin wrote: Fri Oct 28, 2022 3:20 pm
I tend to agree with you but the evidence says otherwise. Yes, coated headers. Lower hose has spring in it.
Does this engine have the single four barrel still or does it have the dual 1850s? If single four, what is it?
Dual 1850s. Same car from my dual quad post
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