I'm in the process of T/Sing an overheating problem on my brother's FJ40 w/ GM 350 crate motor. The temps are fine while running at speed, but when the going gets slow, the water temps go up 240+. There is a big block Camero raditor in it, anti cavity plate in the water pump, just switched to an electric fan. There is an Edlobrock Q-jet carb on it, and a HEI from Summit. the problem is what to check next, the spark plugs were running white, but now with some tweeking on the carb, got them burning better. Reguardless of what we do, we are unable to get the timing to set to anything even close to specs. We do have the timing set to where it runs pretty good, but does have a bog right off idle. Does anyong have any ideas on what to check?

Thanks

THE BOG OFF IDLE IS THE CARB.......SET THE MOTOR TO CORRECT TIMING SPEC..THEN SCREW WITH THE CARB..I HAVE AN EDELBROCH AND ITS A BIG POS.......TIMING MIGHT HELP WITH THE COOLING....

IF IT RUNS COOL AT SPEED........ ITS NOT GETTING ENOUGH AIR THROUGH THE RADIATOR AT SLOW SPEEDS.....AND THEREFORE GETTING HOT....

I WOULD SAY THE ELECTRIC FAN IS NOT PULLING ENOUGH AIR.....
PUT THE STOCK FAN ON WITH A SHROUD.....THEN ALSO HAVE THE ELECTRIC AS BACKUP.....

mine does the same thing, i hvae a flex fan and aluminum radiator...this setup sucks and gets hot pretty quick when wheeling...when it starts to get a little warm, i throw some water on it and rev it at about 2000rpm to suck air adn it drops the temp a lot...i'll be tossing in a 4 row copper radiator w/a steel clutch fan and shroud, and carry a electric fan to act as a pusher if i need it...i'll do this the first couple times out once i get money for the radiator and switch everything around...

With a big block radiator in that cruzah, you shouldn't have any cooling issues. More than likely your not getting enough air flow. Try a 7 blade caddy fan with fan clutch, or a 6.2 diesel fan and fan clutch. It is also important to run a fan shroud, this will help direct the airflow to where it needs to be, the core.... Also try running a coller thermostat 180 degree, and water wetter.
Is your electric fan a puller or pusher. Pusher fans usually work better for providing cooling air, the only bad thing is the front end design of a cruzah dosen't make much room for cooling air to flow. Normally the radiator is about 20% blocked from airflow, worse if you have a winch. Your big block radiator is probably only exposed to maybe 50% of the core for air flow, which is probably equal to a stock cruzah radiator. Might want to consider a few front end sawsall mods!:skull:

If your engine bogs down off of idle, the accelerator pump linkage is more than likely out of adjustment. When you open up the carb, you are getting an air rush with no fuel..

I run a 16" electric pusher/puller fan in front of my radiator, a 7 blade clutch fan on the motor, and have no shroud, but mine stays cool. Fenderwell exit headers also contribute to the heat - I run huggers.

The electric fan is on a switch, and when I do warm up it gets used. To fit it, I removed the wire mesh radiator screen and put the fan in that space. Make custom mounts and DO NOT zip-tie it thru the radiator - the fan vibration turns that plastic into little saws and you'll cut up your radiator. I then cut down the screen and tack-welded it to the inside of the headlight bezel. Gonna more my radiator forward now as well, to make room for a future TC doubler kit. Plenty of room, even with the fan, to come forward at least 1".

The shroud is critical tho if you are having head probs. I want one, just haven't needed it yet....

I have had numerous overheating problems in my Chevy prowered Cruiser. I have tried all sorts of modifications and had little to no improvement. I was sure my truck was posessed. Then I saw an article in one of the 4x4 rags late last Fall that tested various mods to improve cooling. The only thing that seemed to help was a better radiator and a lower thermostat. The shroud, high flow water pump, type of fan, and a few other things had minimal impact.

The timing was the BIGGEST issue for my truck. Get the timing set and then tweak the carb. Once both are set right, the other items are just "gravey". If you can't get the timing to hold - double check the balancer is ok - mine was spun and I had no idea what timing I was running. Also don't forget to disconnect your distributor and other vac. accessories from the carb when setting the timing. You also might check which springs you are using for the mechanical advance in the distributor. You want the stiffest ones available for trail use.

In most cases a high flow water pump will not help. With the high flow pump, water dosent stay in the radiator long enough for the cooling air to disapated heat from the coolant.:skull:

grifen aluminum radiator
red line water wetter
black majic fan
cut center pices out of head light bezel

if you still have problems
a remote oil cooler
then a electric fan for oil cooler

if it was me I would start with the
red line water wetter.
it really does work.
and remove the front head light bezel.

ps some peopple will tell you that the 350
should run at 220 for best performance.