Author Topic: Running way too hot.  (Read 12780 times)

Offline 1979C20

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Running way too hot.
« on: June 25, 2012, 08:18:52 pm »
My truck is slowly killing me inside. I put an edelbrock performer intake with a carter afb 650 on it and I put my distributor back in and set the timing to the idle it was running before the swap. But, I didnt take into consideration the higher plenum and what not so the timing was off. It was running at 210 all the time. So I though my thwrmoatat was sticking. I ulled it.out and it was running at 200 all the time. so I put a timing light on it and tge timing was advanced so far that I couldnt see the mark on the tab. So I retarded the timing, set the idle, and adjusted the a/f mixture. It was running at like 175, nice and cool, with no thermostat. then, it started running hot again. So I put a restrictor in my thermostat and it helped a little. But my idle was all over the place, high then normal then low. I found that my distributor was loose. So I set it back to thw original idle but im still having temp problems. When I start driving it runs alright. But when I stop, it gets a little hotter, and wont cool backdown. It keeps repeating that cycle until its running about 210 to 220 and wont cool back down until I shut it off and let it cool over time. And my oil pressure is about 1/2 psi at idle.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Fairlane514

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Re: Running way too hot.
« Reply #1 on: June 25, 2012, 09:30:51 pm »
You need to run a thermostat, I would go with 180. What radiator are you using, how is your water pump?  Set your timing around 10-12 degrees advanced. With no thermostat the water can't stay in the radiator long enough to be cooled and just end up running hotter and hotter water through the system.

Check the condition of your cooling fan and the fan clutch. 

Are you sure on 1/2 psi oil pressure?   Thats going to cause catastrophic  results.

Offline 1979C20

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Re: Running way too hot.
« Reply #2 on: June 26, 2012, 12:01:51 am »
I have a moroso water outlet restrictor in place of the thermostat. My timing was at 10. I have to hold the idle up at a stop to keep the oil oressure up. The radiator is the stock 3 core. Its in decent shape. Water pump is a brand new reman. If I have my radiator cap off and my truck running I can watch the water moving in the radiator. The fan is good, the fan clutch has resistance when the motor is hot.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline 454Man

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Re: Running way too hot.
« Reply #3 on: June 26, 2012, 12:12:54 am »
Is this the factory oil gauge your reading?

Offline Irish_Alley

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Re: Running way too hot.
« Reply #4 on: June 26, 2012, 12:14:27 am »
running hot at idle is a problem sign of a bad clutch
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

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Offline DnStClr

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Re: Running way too hot.
« Reply #5 on: June 26, 2012, 12:12:29 pm »
Hope it's not a dumb question, but you didn't happen to move the fan shroud did you?
I agree with Irish- it sounds like there's an air flow problem if it cools down when you're moving and heating up when idling.  A 3 row radiator should be good, but it can also be blocking the air flow thru it. Sometimes a wide, single row radiator can actually be more efficient with air flow.  Now that you've increased your air intake into the engine with the new carb and intake manifold to create more power, there's more heat so you might be finding that you'll have to increase your cooling air too.   
« Last Edit: June 26, 2012, 12:37:13 pm by DnStClr »
Don
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Offline 1979C20

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Re: Running way too hot.
« Reply #6 on: June 26, 2012, 08:35:07 pm »
Its an after market oil and temp gauge. Both manual gauges. I havent touched the fan shroud. Nothing blocking it. i can feel the air being pulled through it from the grill. And I was running fine right after I put the intake on. At 170 for about a week until the distributor came loose.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline bobcooter

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Re: Running way too hot.
« Reply #7 on: June 27, 2012, 02:57:29 pm »
When you put the intake gaskets on for the new intake did you make sure to line them up properly and not block any water passages? This could give you plenty of H2o temp problems. Especially since your problem did not start until after your swap. Something to think about...
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Offline thefarmboy21

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Re: Running way too hot.
« Reply #8 on: June 29, 2012, 08:52:52 am »
First off. I run a "gutted" thermostat in my 350, BUT it's in a derby car lol. But 220 I thought was about normal and I've had my 350 go from 60-5psi at idle from being so hot.

Now with that said, I think you have an air pocket trapped in your heads under your new intake. When I built my motor, several others, and anytime I have to drain on and refill....my edelbrock air performer rpm air gap always gets air pickets under it because it doesn't have a crossflow, Just block off.  Mine has bleeder ports tho with 3/8 Allen fittings. First time i fired it up it got WAY hot fast. Cracked those open in the two back corners and all I heard was"pssssssssstttt" then up came some water and tightened it up. Instantly cooled down. Then it was still running a little lean. Carb/timing tweaky and WHA LAH!!!  So my vote is trapped air pockets. 
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Offline Fairlane514

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Re: Running way too hot.
« Reply #9 on: June 29, 2012, 04:06:38 pm »
My 84 2wd short bed has a Goodwrench 350. I have a new AC Delco fan clutch, new aluminum radiator from"Radiators4less" (it uses original shroud and mounts), new standard flow water pump from NAPA, and a 180 thermostat.  It runs at 180 with A/C on in Texas heat.  I also have ceramic coated shorty headers and 2 1/2 dual exhaust.

Offline 454Man

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Re: Running way too hot.
« Reply #10 on: June 29, 2012, 05:10:34 pm »
What 180? Dude really thats shocking in tx heat mine runs 200 all day

Offline Fairlane514

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Re: Running way too hot.
« Reply #11 on: June 29, 2012, 05:41:34 pm »
OK, maybe 185  ;)     I have some auto gage electric gauges and it reads 180-185

I will also add, I have my initial timing set at 12 degrees advanced, with additional 10 degrees of vacuum advance (hooked to full manifold vacuum source).

There is an argument that running full manifold vacuum helps the engine run cooler
« Last Edit: June 29, 2012, 05:44:53 pm by Fairlane514 »

Offline 454Man

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Re: Re: Running way too hot.
« Reply #12 on: June 29, 2012, 10:07:34 pm »
OK, maybe 185  ;)     I have some auto gage electric gauges and it reads 180-185

I will also add, I have my initial timing set at 12 degrees advanced, with additional 10 degrees of vacuum advance (hooked to full manifold vacuum source).

There is an argument that running full manifold vacuum helps the engine run cooler
True manifold over ported, but power timing the dizzy is the key. Aparently you cam/ engine combo loves the timing. I have the comp cams high energy 260 and initial is set @ 10° haven't power timed it yet but after a new dizzy and carb will do.

Offline Fairlane514

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Re: Running way too hot.
« Reply #13 on: June 29, 2012, 11:56:03 pm »
I have the stock Goodwrench tiny cam.

Offline 1979C20

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Re: Running way too hot.
« Reply #14 on: June 30, 2012, 12:30:16 am »
Well, my fan clutch is in good shape, my radiator is flowing nicely. No restrictions anywhere that I can find. A few people have told me that it may be because of my burnt spark plug wire and fouled plugs on top of not knowing where my timing is set. I just bought a set of plugs and wires because I needed them and im going to swap them out tomorrow. Ill see if that helps. Im going to time it after swapping them. My fan shroud is good, my intake gaskets are correct, I ran no thermostat in my truck for a couple weeks and it ran at 165. The restrictor is just to slow it down a bit to help the warm up and cooling. Ill post back after I get it all done if theres any change.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF