[YVEYANT]

The fuel is probably tarnished and bad. You should consider dropping the tank and flushing it and the lines out, then have the carb rebuilt, change the fuel filter and go.

[Dan Linebarger]

I recently had identical symptoms on my '75 Jeep.
The problem was the radiator. The small horizontal fins had rusted and pulled away from the verticle flow tubes. You really couldn't see it that well.
I installed a new radiator that had 50% more tubes. The temps dropped from 230-240 to 180.
In an effort to run cool, I had dipped the block, made sure the blocked flowed good. Had the radiator "cored". Installed a fixed fan, no clutch, added an oil cooler.
All the time, the radiator was just old.

[jeff68bird]

Originally Posted by Dan Linebarger

I recently had identical symptoms on my '75 Jeep.
The problem was the radiator. The small horizontal fins had rusted and pulled away from the verticle flow tubes. You really couldn't see it that well.
I installed a new radiator that had 50% more tubes. The temps dropped from 230-240 to 180.
In an effort to run cool, I had dipped the block, made sure the blocked flowed good. Had the radiator "cored". Installed a fixed fan, no clutch, added an oil cooler.
All the time, the radiator was just old.

dan that would be great if that is all it is. i think the easy thing to do would be to try another radiator ist. thanks for the reply. if that doesnt work i will move on the some of the other suggestions.

[Dan Linebarger]

Jeff,

I hope that is all it is. When I bought my 70 Goat, it had similar symptoms of your car and we discovered a head gasket leak when we tore down the motor.

Hopefully for you, it is just a cooling problem and the block is not compromised.

Good Luck!!!

Dan

[jeff68bird]

ok update on problem.intial timing set at 10. changed radiator with a new 3 core. hooked up fitting to upper radiator hose and blew air back thru engine and out lower hose and also out heater hose nipple on head. flushed block again. problem seems to be better.now motor will run a lot longer .motor stays around 180-190 but then after a little while still creaps up to about 210. does not blow out the overflow but is still running a little hot. someone had mentioned that vacuuum advance can cause motor to overheat. can someone explain to me how the vaccum advance comes into play at a idle. when i rev up the motor and look in the little window of the distributer i dont see any movement on the plate the points are mounted on? also carb still has a big stumble just off idle? still using the thermal vacuum switch. which has 2 lines on it . one to vaccum advance,1 to back of carb at vaccum tee,one to front of carb. does it matter how the lines are attached to the switch.? . as far as something being cracked i pressure tested the motor thru the hoses with 100psi and it seemed to hold pressure also compression test was 135-140 per cyl. thanks for any help jeff

[pinballDan]

Hi Jeff

I had the same problem you are describing. I found that the four blade fan and the large water pump pulley at idle slow down , where the water pump flow and air flow is to low at idle. I changed the crank pulley and the water pump pulley and the 4 blade fan to a/c pulleys and either a clutch fan or I installed a flex fan. I also run a 160 stat in it and at 100 out it will idle at 190 and runs around 170 - 180 cruising for ever and it is a 463 that runs 11.40s hope this helps.

Dan