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

[jonah]

Yes, I am running a microsquirt to run the TBI.

When I was running with no thermostat it would run at about 195 on flat ground. Not sure why it would run a bit hotter with it wide open when it will run at 180 with a 180 thermostat as long as no hills are around, lol. Coolant moving too fast?

[curtis]

That is why we would put the thermostat back in. The comp works the timing and Tb off the temp. I think (I'm old school) So you better talk to Art and Kurt.

[6spdYJ]

Running no thermostat allows the water to flow through so fast that the water doesn't have time to dissipate heat in the tubes. I have seen a weak radiator cap cause overheating. I even had a brand new Stant cap fail; opened the package, installed, started and overheated. You may consider trying a higher pressure cap.

[jonah]

My timing isn't controlled by the computer (yet). It is still running a regular 4 pin HEI distributor with vacuum advance.

I am running a new Stant 16 psi cap now, I was hoping the old one was bad but it acts the same. It doesn't seem to be losing pressure even when it gets up to the 230 mark. When you had the bad cap what did it act like?

[6spdYJ]

The puke tank was always gurgling immediately after shutting the engine off. Within a week, it would not handle sitting at idle for more than a few minutes without boiling over. With the one off the shelf, I had replaced the radiator due to leaking tank o-ring on a stock aluminum radiator so I figured replacing the cap at the same time was a good idea. It boiled over at idle in the driveway within 10 minutes. Another new cap cured it. Without boiling over I can't say for sure that that's your issue, but more pressure in the system will put more pressure against the tubes and allow for more heat transfer. There is of course a balance where too much pressure will not be good either.
Your radiator should be plenty big enough. For a few years I ran a 402 on a stock 2-row radiator from a 250 with no heating problems. It had headers, full fender wells and hood. I can't help but think that the shroud being so close to the back of the radiator is your biggest issue. Is there any room to stand-off the shroud; maybe about 1/2"? If you need a bit more room you can use flat head socket head cap screws to hold the water pump pulley on. It might buy you up to 1/4". I know it sounds like a lot of effort for a minimal return, but I understand your limited real-estate. It would allow the fans to pull a bit of air from the sides and have a venturi effect on the areas pocketted by the shroud. As air from the sides is pulled behind the fins, it can provide a slight low pressure to pull a bit more air through the fins from the front. It's something worth trying. Have you verified that the fans are turning the right direction?

[vwtipeii]

sorry to hear you are having these issues after all the work you put into your new motor... I kind of know feeling my friend

[jonah]

Did a little test with an IR camera to see the flow of the radiator. Here is one of the shots that shows some uneven flow. You can see the bottom 3-4 rows are very cool and a tendency for the top to warm up quicker. This would have seemed pretty conclusive except that after running for a while the entire radiator would even out in temp. But it did seem like the top was flowing more.


So I decided to get a new radiator from Champion Radiator. Although I found it on ebay I was able to pick it up locally as the father of the founder of Champion Radiator lives in the neighborhood. It is a downflow, three row (.63" wide tubes), all aluminum radiator made for runnng a GM motor in a later CJ. It fit fairly well in my early CJ but I did have to cut the headlight buckets to make it fit, a small price if it gets the job done. It claims to be capable of handling up to 600 hp so hopefully it will be good. I reworked my fan and shroud set up and I have to say I am getting much better airflow now. Before the fan exhaust came out at strange angles and had dead spots all over. Now it is pulling straight through. Plus the mounting is much simpler with the radiator, shroud and fans all separate but mounting to the same support. My only problem was I broke one of the fan blades taking it apart so I am off to the junkyard to get a new one tomorrow.

the new setup.


Mounted in reverse for easy fabbing of the brackets.


Here it is installed the correct way. Fired it up and it can idle on one fan at 177 (180 thermostat). Can't wait to get both fans running and see how it works on a hill climb.


Zoobi mentioned a problem he had with overheating an a incorrectly ground cam. I was able to check the valve timing, even though I didn't have the specs for the cam I was able to measure the lift and TDC and see what the overlap was. It measured out evenly with .050 of lobe lift at TDC on intake and exhaust. Also the valves close evenly on either side of TDC. From what I read this would seem to indicate neutral valve timing, so I am hoping that eliminates the cam as a possible culprit.

[daniel_buck]

Hope that works for you Jonah!!

[6spdYJ]

The downflows don't require as much from the pump to flow through the tubes so this will probably help a lot. Have you checked the airflow with the new one?

[jonah]

I sure hope this works! Looks like I am going to run out to Calico on Sunday to give it a proper test.

I did check the airflow and it is better. It is more even over the entire radiator surface whereas before there was much more variation. Plus I picked up a new fan yesterday from the pickapart and replaced the one that had a cracked blade.

I did a quick drive around town yesterday and depending on where I set the fans to go on and off it would run anywhere from 172 to 187. First I had the fans come on at 185 and turn off at 180, this caused it to run up to 187 then cool to 175 and it would just keep going up and down. Then I made the fans come on at 180 and turn off at 170 so once they came on they stayed on the entire drive. The temp settled at 172 and was steady driving and idling. I need to figure out the best settings for the fan and find a hill to see if it really works....

[vwtipeii]

I hope it all works out... I hope to be able to join you again out there before xmas!!

[jonah]

Ran around calico yesterday. Never broke 185 degrees although the temps were cool and the hills out there are not too long but it is looking good. I also had a friend ride along and he spotted a lean condition on my AFR guage when under part throttle so it is likely that it was contributing to the issue. So it looks like I need to really spend some time dialing in the fuel tables on the Microsquirt. Overall feeling pretty good about everything.

Pic of TomTom wedged in pretty good:



And me crushing my fancy spintec muffler because I was staring at the guages all day instead of watching where I was driving, lol.

[daniel_buck]

nice!! :-D

[jonah]

Not knowing when to leave well enough alone...

I got the V6 running good, so I decided to take it out and put in an LS. Out with the old:




In with the new (sort of):


Closer:


It is going to be tight but I think it will go. To make space I am ditching the np205 and going to a dana300 using the novak adapter, this will pick me up about 3.75". I am going to try and place the front of the motor in the same place so the transmission and transfercase will move back about 4.5-5". So the output will be about an inch or so back. The 300 will allow me to mount everything a bit lower so I think my rear driveshaft angle will still work. Plus I will pick up some gearing, 1.9:1 on the np205 and 2.62:1 for the Dana 300. Crawl ratio going from 58:1 to 78:1, probably too slow for my driving style, lol.

Word of warning on buying LS motors, that I am sure everyone else already knows... It is hard to tell if you are buying a 5.3 or a 4.8 without looking inside. I was sold a 5.3 but when I opened it up at home I found I had a 4.8 on my hands. Since they run the same block, heads, intake etc. it is easy to mistake. The difference is inside: 4.8s have flat top pistons and a shorter stroke crank (3.27 inch). 5.3s have dished pistons and a longer stroke crank (3.622-inch). Also look out for 706 heads, one of the castings is known for leaking, you can tell by looking under the rockers for a casting mark that looks like a AA battery (I of course got these heads). Anyway, I swapped the heads and I am running it.

In the true nature of Opy, I am DIY'ing the wiring harness. I followed the advice found at www.lt1swap.com, pretty easy to do once you know what year you are messing with (did I mention the motor was sold as a 2002 but was actually a 2003). Brendan at lt1swap.com flashed the PCM for me taking out the security, emissions and transmission functions. Running the stock tune since I am not modifying the motor at this point.

Hooking it up to my SM465 looked tricky at first. There are conversion flywheels at a high cost $300 and up. There are people who bolt the old school 11" clutch to the new metric flywheel but it involves reaming the mounting hole and using metric bolt instead of the proper shoulder bolts. But as it turns out you can just buy a flywheel and 12" clutch (has the same 10 spline 1 1/8" input) for a 2005 silverado with either a 4.8 or 6.0 then use the good old small block bellhousing and you are good to go. The only special thing you need is the extended pilot bushing

Sachs - Flywheel Part # NFW1050 from amazon: $60
Chevy Extra Long Pilot Bushing - 910-25800 ebay: $15
I am using the 6.0 clutch (LuK 04-201 Clutch Set) which is rated for higher torque but more expensive from amazon: $212.
but you could use the 4.8 clutch (Luk 04-205) which is a lot cheaper at $150

I decided to use the bigger clutch incase I ever upgrade the HP on this motor.

Everything looks like it is meshing just fine so we will see how it goes! Now to go cut up the firewall...

[daniel_buck]

Ruh roh! :scooby:

Can't wait to see it in action with the V8!

Still gonna be able to fit the exhaust inside the frame rails?