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Engine temps crept way up this summer-first time i saw it-ever!

2K views 12 replies 8 participants last post by  JohnMc 
#1 ·
56 Bel Air HT 2DR
Stock 327 2bbl
older 3 row Rad in V8 position, no shroud
160 thermostat
original OEM style point dist (may be the issue)

I verified temp was at 185-190 with heat gun and thermometer while running
Temp sensor in intake position

last summer it reached 108 outside and this thing never crept above 190 engine temp in parade traffic. This year it got to 104 outside and crept up to 230 engine temp. I think it may be the vacuum advance stopped working???

What say you all??
 
#3 ·
It could be a variety of things but here's a few that may help in checking it out.
1- Water passages in radiator partially clogged.
2- Any water hose starting to inside rot slowing circulation.
3- Slipping fan belt.
4- Fwd. edge of fan too far from radiator,should be 1/2, 3/4 ".
5-Thermostat fails to fully open,does not open a correct temp. or too high a temp.
6-Late ignition timing.
7-Overheating at one cyl. due to rust or scale.
8-Centrifugal advance fails to advance spark as eng. speed increases.
9- Install a fan shroud.
Good luck,hope this helps.Keep us posted. :anim_25: :bowtieb:
 
#6 ·
It could be a variety of things but here's a few that may help in checking it out.
1- Water passages in radiator partially clogged.-COULD BE BUT I HAD IT RODDED OUT AND REPAIRED.
2- Any water hose starting to inside rot slowing circulation.-ALL NEW HOSES
3- Slipping fan belt.-NEW BELT BUT I CHECKED ANYWAY, ITS ALL GOOD
4- Fwd. edge of fan too far from radiator,should be 1/2, 3/4 ".-ITS A FLEX FAN ABOUT AN INCH AWAY
5-Thermostat fails to fully open,does not open a correct temp. or too high a temp.-I PUT IN A POT OF WATER AND VERIFIED THAT IT OPENED AT 160
6-Late ignition timing.-THIS I THINK IS THE ISSUE AS ITS THE ORIGINAL DIST.
7-Overheating at one cyl. due to rust or scale.-I DID NOTICE THAT A COUPLE OF CYLINDERS ARE RUNNING VERY HOT COMPARED TO THE OTHERS
8-Centrifugal advance fails to advance spark as eng. speed increases.-I WOULD THINK A NO ADVANCE EVENT AT IDLE WOULD CAUSE IT TO RUN HOT NO?
9- Install a fan shroud.-I MAY DO THIS Good luck,hope this helps.Keep us posted. :anim_25: :bowtieb:
 
#5 ·
My self as well.
It hasnt got up to 230 again since that day last month-very strange. Last weekend I let it idle for hours and drove it all over and it never crept above 190 since. I couldnt get any hotter no matter what I tried. I measured with a thermometer and heat gun which showed 185-190 at the water neck.

Conversly, after we got it home that night from the parade recently I measured temp with the heat gun and it was actually 230 at the water neck as well as 230 on the aftermarket guage. So I know the guage is accurate.

Side note-I have it on ported vacuum at base of carb. When you remove advance line there appears to be NO VACUUM at all?

With no vacuum advancing the timing at lower RPM's wouldnt that cause the timing to retard at idle causing motor to run hotter?

In my case when you get moving, the centrifugal weights I would think take over as well as increased airflow over the rad bring the temps back down to normal(normal in my case is 185-190).
 
#7 ·
Not sure what carb you have, but usually the port at the base of the carb is full manifold vacumn. I have a holley and that's the way that one is, and the ported vacumn port is up higher by the metering block. I have heard some people say ported vacumn will maybe make the car run a little hotter. Did you just change where you run the vacumn advance?
 
#9 ·
The carb is a holley 2bbl off an old 59 ranchero belive it or not.

Its strange in that you can pull off the rubber advance line while the engine is running and there is very little if any vacuum at all at the fitting.
 
#8 ·
Did you say PARADE? I can see why it heated up so bad. A couple hours not getting any decent air movement… Parades are not good for old cars in my opinion, unless they're only a few blocks. Our parade here is 2 miles, you don't see many old cars attempt it.
 
#10 ·
You betcha, PARADE traffic with no less than 1000 cars that year chugging along. George Lucas was here in his hometown that year.

My 71 SS 454 Elco never crept above 190 the entire time with the A/C on!!!!!!
This 56 of which we speak about never crept above 195 either the whole time, and we wern't moving at all.

That's what's got me baffled. Something has changed to cause this.
 
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