Cj3a Cooling

Working on my CJ3A again. It has a fresh rebuild on a Buick 231 V6. I rebuilt the holly 390 today and was able to run it a while. still not running great, but got it up to about 205 degrees pretty quick (10 minutes) and I shut it down. Electric fan kicked on at 180 from sensor in block, but aluminum radiator not hot to touch. I'm pretty sure I put the 180 degree thermostat in correct and it was new. I was thinking of taking out thermostat and trying it. I've never use an aluminum radiator before, am I missing anything? It's at my in-laws so I go months without working on it and I forget where I left off the last time. Thanks, Cole

 

make sure there is water in the radiator, leave cap off, start engine and pour more water in the radiator as it warms up till full, then when water starts to expand out the filler neck close cap.

If you're sure everything is good mix antifreeze/water.

 

Thanks for usual fast reply. I already added coolant thinking, what could go wrong. I put a gallon of coolant in plus water initially. It was running out when I put on cap. I would think radiator would have some heat, with engine temp at 205. To me it's not circulating. I was going to try without thermostat today, maybe it's bad. I will keep trying. Got the week to make progress.

Thanks, Cole

 

Take thermostat out and put in water in a pot on the stove with a thermometer in the water and the thermostat off the bottom of the pot. Check to make sure the thermostat opens when its supposed to. Also make sure you didnt put it in backwards.

 

Also make sure you have all the air burped from the system. If squeezing the upper hose results in bubbles-you don't. My experience with aluminum radiators is that the tubes are usually bigger in cross section and they flow more easily than the brass versions. They will frequently drop the coolant temp 15 degrees due to the better thermal conductance of aluminum versus brass.

I also do not like electric fans. A large mechanical fan in a well fit shroud will flow more air than anything else. You pay for it in mileage because it uses more energy but off-road crawling, it is hard to beat. If you stay with electric-like the mechanical's-it too needs shrouded to do its job properly. Portions of the radiator not shrouded will be very inefficient in removing heat from the system.

 

Thanks for the support! I just got in from the shop. I pulled out thermostat and things seem to be working correctly. I can visibly see coolant moving through radiator. Temp slowly rose, as it should. So that problem seems to be somewhat solved. I will boil thermostat to see what's up. I'm 99% sure it was in correctly.

Motor running rough, with raw fuel running out of exhaust. I just rebuilt carb and it's running better, but not close to dialed in. I'll try to adjust floats, hopefully that does the trick. I don't know what else it could be. It's a used carb, so you know how that can go.
Spaced transfer case down to clear headers from body. It did help, not touching any longer, but I think I need to lower the motor slightly as well. Worked on wiring the rest of the day. It's painfully slow, but I'm using a gm tilt column and no pre-made harness.
My brother in law is putting in my windshield glass tomorrow. That should help me see things coming together. Thanks again, Cole

 

Make sure your fuel pressure is not too high. Make sure if you're using HEI that your plugs are gapped correctly. Make sure your timing is correct and buy a vacuum gauge to set idle screws right. Most will also measure fuel pressure. Follow the instructions that come with it. Mine is a Harbor Freight model. Works good. It will tell you a lot about whats up with your particular engine. Its kind of a magic tool.

 

As always thanks for advice. I'll try to go by harbor freight and pick up vacuum gauge. I think fuel pressure should be around 5-7 psi. I tried to start again today to do some trouble shooting. Would not really crank like timing too advanced and or battery weak. I was using a deep cycle wheelchair battery, because of the size. I bought a new battery thinking it was the problem. No better, so I thought it was something with timing that I set yesterday at 15 degrees BTDC. So I retarded and still no go. I'm thinking starter now. It was original with salvaged motor. I'll swap that out and see what's up. I'm using the original willys ground cable to battery mount, then I ran a braided copper to motor from battery mount. Maybe should be directly mounted to block?
I got glass mounted in frame and installed rubber seal on bottom of frame. Didn't get it mounted on jeep. I riveted the welting to top of grill. I installed later model front park/ turn signal lights. Machined spacers on motor mounts 1/4 inch to lower motor, to further fix header body clearance. Thanks, Cole

 

Not a real good day today. I bought a new starter and the problem was still there. So I pulled out the plugs and there was quite a lot of fuel in the cylinders. With the plugs out, coil disconnected and fuel pump disconnected, it turned over and fuel blew out of cylinders. I checked the oil and it had a strong Oder of fuel, so I drained oil. It had quite a bit of fuel in oil. I hope I didn't ruin my rebuilt engine. Not sure if it was the carburetor or the new mechanical pump, pumped way high pressure. On a better note, I did get the windshield mounted on jeep. I thought it would be a thirty minute job, but turned into three hours. Using the rubber seal really made it a challenge. I had to modify the latches, making them longer. Tomorrow is my last day here so I need to make it count. Probably motor on hold for now. I will probably try to finish wiring and building seat mounts. Cheers!