car it is still running hot above 210 at idle. I have a ir thermometer and at the water neck radiator uper and lower i am reading the same temp which is 150+ no more than 170. Ihave a 160 thermo installed but when i read the sending unit in the head it reads anywhere from 210 on up. The headers are also pegging out the themo it reads all they way to 575. Is this causing my temp gauge to read wrong. all of this is when the car is parked at idol after about 15 min. i need help please The current setup on my car is a 160 thermo, edlebrock performer with 1.5in spacer 600cfm holley 4160 carb. also i have a new factory style rad. running a 10 and 12 inch hyden electric fan with a temp switch that cuts on a 180. i was told in a previous thread that with my cam a performer rpm and 750 doublepumper would be great. I am thinking about going with the rpm air gap and 750dp. Can the carb and intake being to small result in this kind of temperature reading . again here are the specs on my cam Part Number 12-512-5
Engine 1955-1998 Chevrolet
262ci-400ci
8cyl.
Grind Number CS280TLS-6
Description

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Intake Exhaust
Valve Adjustment 0.018 0.018
Gross Valve Lift 0.53 0.55
Duration At 0.02 Tappet Lift 280 288

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Valve Timing At 0.05
Open Close
Intake 19 51
Exhaust 56 23

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These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 250 259
Lobe Lift 0.3534 0.3667
Lobe Separation 106

--------------------------------------------------------------------------------

Recommended Valve Springs 986-16

Please any advice would be appriciated I am puzzled some times it runs hot and other times the gauge is saying its not so i do not now.

 

oh yea the car has 10.5 to 1 compression and about 100 miles if that on a new motor

 

also could the temp sender be getting to hot in the head being between the headers like it is. should i relocated it to the intake? Also the timing is supposed to be set correct but i found out today that my vaccum advance was sticking. Do i have to retime the car or is it okay . the advance was not even moving.

 

Your cooling system seems to be working fine, and yes with headers you can expect the temp sender to read a little higher then norm.
Sounds to me like your 600 is running to lean on the fuel mix. may need to jet it up a size or two. Try add'n a O2 sencer too, it will help you get it close.

 

If your vacuum advance is sticking, your idle timing is probably excessively retarded and may be causing heating at idle. On the other hand, it wouldn't hurt to relocate the sender to the intake manifold if you have a spot for it. If you don't have a hole for it, some of the thermostat housings have provision for a sender.

The IR readings you are getting indicate that you have a sender issue, but don't ignore the timing problem, as it will certainly cause excessive heat, especially at idle.

 

which way do you move the distributor to advance or retard the timing

 

Advance the distributor by turning counterclockwise. With the vacuum advance plugged, you want to see about 34-36* total timing, with all the advance in by around 3000 RPM. The initial advance will probably fall in the 8-12* range, depending on how much centrifugal advance you have. The vacuum advance will add another 14-16* at full vacuum. Typically, with the vacuum advance operating, you will see around 20-25* advance at idle. Can't give you an exact number because I don't know what your engine specs are, but these will get you close.

 

Check the sending unit. I have a problem with mine. Checking roger's corvette clock website I noted that his unit is meant to be put in without any thread sealant. Apparently it needs the metal to metal ground. Maybe this is a problem?

carbster

 

Thread sealant is a problem on sending units, but it usually produces a false low reading due to poor grounding.

 

When you take the readings, you have to have the gun close to what you are reading. The readings for the radiator necks should not be the same if coolant is flowing through the engine. That laser dot from the gun is only a guide of where it's going to read, and not how big of an area it's going to read from. Are the fans running when it gets hot; and where is temp switch for the fans located?

Jim

 

The fans cut on at 180 according to my temp gauge the temp switch is located on the driverside fender by the hood hinge. The temp probe is attached to the bottom of the radiator it is one of those cheap switches you buy at autozone.

 

Your thermostat is set for 160, and the fan sensor will send 180 degree coolant(minimum) to the engine. That might be why your upper and lower radiator temps are the same; because the thermostat is open all the time, and coolant is circulating all the time. The sensor temp needs to be lower than 160 (in this case).

 

okay timing and carb are set the temp got to about 190 sitting at idol while i was timing and adjusting the carb. So i took it around the block for about 15 min temp never got above 210. Its about 90 here in alabama with hi humidity. came back let it sit at idol while i opened the garage and when i went to pull it in the temp said it was about 225 maybe alittle over this was after driving i am assuming it was heat soak from me driving it around.

 

Check all your seals around the radiator also. If your fans aren't shrouded, you may need to do that too. The object here is to make the fans pull air through the radiator from the front end. Not just recirculate it around the engine compartment.