overheat question?

[hachicoupe]

Alright guys, I need a little help with ideas.
My car overheated the other day pretty bad, I had just done a little more tuning and I was letting it idle high (~2000rpm) to aid my engine break in.

Here's what I do know:
-no signs of oil and antifreeze mixing
-no white smoke
------that makes me assume my head gasket is fine
-radiator is not plugged
-water level was full
-fan was on
-I do not have a thermostat
-all my hoses are good

My ideas for possible culprits:
-bad radiator cap
-I may have retarded it a little too much, (once my carbs stopped backfiring, I stopped retarding it)
-plugged water passage in head
-fan may not have been powerful enough to cool the radiator at idle with elevated rpms

Any help or suggestions is appreciated.

[baldo]

Two things we need to know right away to help you. 1- Break in the engine? So it is new right? 2- You might of retarded it too much? If the engine is new and you "set the timing" until it stopped backfiring, stop! If you dont know If your timing is wrong it can cause your engine to overheat. That could be the problem right there. Also by "carbs" do you have dcoes? Just because they backfire does not mean its the timing.
It can also be air in the system..... Ok your turn again............

[mikealike]

Alright guys, I need a little help with ideas.
My car overheated the other day pretty bad, I had just done a little more tuning and I was letting it idle high (~2000rpm) to aid my engine break in.

Here's what I do know:
-no signs of oil and antifreeze mixing
-no white smoke
------that makes me assume my head gasket is fine
-radiator is not plugged
-water level was full
-fan was on
-I do not have a thermostat
-all my hoses are good

My ideas for possible culprits:
-bad radiator cap- EASY FIX
-I may have retarded it a little too much, (once my carbs stopped backfiring, I stopped retarding it)- timing is set by performance not by popping for the carbs, side drafts will pop at times. I normally set the timing at 16@idle and 30-35@ 3000 rpms depending on gas and setup
-plugged water passage in head- if you rebuilt the motor cleaning is the very basic.
-fan may not have been powerful enough to cool the radiator at idle with elevated rpms- cheap fans will not pull enough at 0 mph, fans are only good for the vehicle @15 mph or less.

Any help or suggestions is appreciated.

[hachicoupe]

Two things we need to know right away to help you. 1- Break in the engine? So it is new right? 2- You might of retarded it too much? If the engine is new and you "set the timing" until it stopped backfiring, stop! If you dont know If your timing is wrong it can cause your engine to overheat. That could be the problem right there. Also by "carbs" do you have dcoes? Just because they backfire does not mean its the timing.
It can also be air in the system..... Ok your turn again............

Fresh rebuild. Dual solex addhe 40mm carbs. I had it set to 0 degrees, then retard, richen, retard, richen until it ran well without backfiring. Let it run ~35 minutes at high idle, I heard the radiator cap hissing, then shut the car off and relieved pressure. I thought about air in the system... what's the best way to bleed the air?

[hachicoupe]

I just got a chance to play with the car today.
Absolutely NO smoke.
I set the timing to TDC.
Installed a water temp gauge.

Car is still overheating at idle.
My HG is good.
My electric fan is functional.

My Ideas:
Maybe my water pump did go bad???
Plugged water jacket.

Any other thoughts???

[toyotero2dend]

Check that the rad. Is not clogged,,,you can disconnect the hose that's on the back of the head that goes to the heater control valve and there you will see if water is circulating ..(with car on)

[hachicoupe]

Check that the rad. Is not clogged,,,you can disconnect the hose that's on the back of the head that goes to the heater control valve and there you will see if water is circulating ..(with car on)

Water is circulating. Radiator isn't clogged. I think my water pump DID fail. I tried everything else. Added a second fan, tried a thermostat, then tried it with the thermostat guts cut out, it still wants to overheat. All my hoses are good. Other than my water pump, I'm clueless.

[baldo]

Is the belt tight? It can be the radiator cap also. Then the water pump will be the problem. My head just spins in circles when you explain your ignition timing method. I will try to help and say this again, fix your timing then try to figure out the problem. I know these cars are old, but if setting the timing was that easy...........

[73te27]

First set timing right. Dont mess with initial, set 32 total to start, you can adjust to preference later. If water is circulating, highly doubt would be the water pump.
Is fan hooked up correctly? You change polarity to change direction but you also have to turn the blade around. Check the radiator, are the fins nice and solid?
Duals and headers usually run cooler then stock unless you are lean. Check plugs but after you set timing. You the one who got 30 something mpg? That is better then stock so you are probably lean. Rap the motor in neutral right off idle, not gently, really floor it. Does it sound like it turns off for a second then rev up? That is a lean bog.

[toyotero2dend]

My new set up was overheating ,,, timing was off ,, no thermostat !! Adjusted timing,,added a thermostat ,,set up the fan to pull ,, took the cover that's on the bottom of the engine off ! Overheating issue fixed... Hope my lil input helps