CJ3b....That is what the vin tag says.

[daniel_buck]

mount some compressed air cans upside down pointing at the radiator, an emergency blast of frost ready at hand for your escape

[dirtman13]

HBPD will be on you like fly's on $#!t.

Isn't navel jelly for rust? Is that what your seeing or is it calcium from not using distilled water? I ask cause if it has calcium you might want to do a lime-a-way treatment.

[jonah]

Yeah, I would probably get shot after the first 100 yards, lol.

I just have rust flakes, no calcium. I think I picked up some from the second motor I had (a former boat motor) and a bunch from this current one. I am hoping it is clear now. If not I am going to a bigger radiator and fan system. I kept the factory headlight buckets which take up a lot of room, if I ditch them I can add four inches of width to the radiator. Or if I would move the engine back a couple of inches my life would be a lot easier, I just don't want to get that into it right now. I could just avoid all trails with hills....

[6spdYJ]

I just looked at the shroud you have. Your fan spacing in the shroud looks good. It may be that the shroud is too close to the back of the radiator. You definitely have plenty of fan, but imagine the air coming straight through the fins and then being slammed into a block wall just as it exits. It can actually sort of pool - if you will - and not allow good air flow in these sections. The air drawn right in front of the fan openings is probably screaming through.
With the engine at running temperature and the puller fans running, hold a ribbon of light paper (kleenex or toilet paper) about 2-3" away from the front of the radiator face in various areas. It will pull toward the radiator like a kite tail. See if you have any dead spots. It can also be that if you have dead spots, the areas right in front of the fans have the air getting ripped through so fast that there isn't enough transfer of heat to the air. If you have a laser temperature scanner, sweep the surface of the radiator to see if you have hot spots that correspond with less air flow.
Another thing to consider is that pusher fans will partially block air flow into the radiator at higher speeds. Granted this isn't much of a concern at low speeds, but it's a possible contributing factor.
Have you tried a flow-kooler disc on the impeller to boost your flow? All it really does is fight cavitation, but it can help to keep more water than bubbles in contact with the fins.

[jonah]

My fan spacing is pretty tight, but I am out of room up there so unless I move the motor back ore stretch the front (neither of which is a small project) this is the best I can get. The 12" fans from a Town and Country are not super powerful but they do move enough air to keep it cool at idle, doing the ribbon test the airflow is pretty even all around, just slightly stronger at mid fan blade. I might have to go back to a mechanical fan and maybe try to fit an electric pusher if I can find the space. One thing Kevin noticed about my fans is that they do not blow the air back over the motor but instead more out to the side, the air comes out at a 45 degree angle in stead of a straight out of the fan, kind of strange.

I did a couple of tests. I let it idle in the garage and covered the bottom half of the radiator and the temp stayed right at 180. I then blocked the top half of the radiator (bottom half clear) and the idle temp settled in at 182. Went for a drive and it would stay in the 177 to 182 range all the time.

Then since I don't have a laser thermometer, I stuck a meat thermometer in the radiator in a few spots. I get a 10-20 degree drop from the upper cores to the lower cores, not sure if this is normal or if I still am not getting good flow at the bottom (where I suspect it was clogged up from the rust chuncks).

[curtis]

1. What is the flow like?
2. Check the thermostat ?
3. Check timing ?
4. Check heads and block.
5. Air bubble?

[RAT]

You should a delta T in the range of 20-40 degrees f across the radiator. The higher the delta the better. Youre at the low end of the efficiency range.

[jonah]

You should a delta T in the range of 20-40 degrees f across the radiator. The higher the delta the better. Youre at the low end of the efficiency range.

Good to know, I am going to get a better thermometer and recheck a bit more carefully and report back.

[COLOR="#0000FF"]
1. What is the flow like?[/COLOR]
Seems ok, when running cap off I can see it moving.
[COLOR="#0000FF"]2. Check the thermostat ?[/COLOR]
New, and seems to work fine. But, have tested with different thermostat and no thermostat and it behaved the same regardless.
[COLOR="#0000FF"]3. Check timing ?[/COLOR]
My centrifugal was not operating perfectly. I had about 12 degrees initial and the mechanical was adding about 14. When vac was added in it would give about 10 more. Yesterday I cleaned the weights and pads, and went to a lighter spring set so the timing comes in earlier (all in by 3000 rpm). Now I am getting 20 out the mechanical, set it for 36 total (initial and mechanical). But even if it was only running at 26 degrees at WOT would that be enough to heat it up? Anyway, need to test it with the new timing.
[COLOR="#0000FF"]4. Check heads and block.[/COLOR]
New head gaskets, did block check and it shows no gases in the coolant. Also did leak down and compression tests, all normal. Have not done a pressure test on the coolant system.
[COLOR="#0000FF"]5. Air bubble?[/COLOR]
I have bled it every which way and I am pretty sure all the air is out. That said my radiator about even with the motor and the top hose does go about an inch above the radiator, so it is a problem spot. But it has always been this way and it never gave me trouble.

[RAT]

If you have several tubes blocked in the radiator the water will flow right around them. But the reduced surface area will cause loss of efficiency. If you have an infrared thermometer, you can check each tube individually. Cold ones are clogged, hot are not. A bi-metal contact thermometer will work as well if it has a small enough contact head.

[RAT]

And I forgot to mention, I have several IR types you are welcome to borrow.

[jonah]

I will take you up on that. Going to be working in the garage anytime soon?

[curtis]

I would say radiator not big enough for new engine or not flowing enough.

[jonah]

That seems to be what the evidence is pointing too. I hope my current radiator was clogged because I can not fit much bigger in there. Flow wise there is a high flow pump made by TA performance but at $200 I would rather not use it, but at least it is an option.

[RAT]

I'm here all weekend. Home tonight as well.

[curtis]

Back in the old days when we put Chevy v8' s in old Cjs We would port out the manifold and thermostat housing. Then gut the thermostat so it didn't work. But put it back in to slow down the flow some.

Does it have a computer.