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V8 MJ cooling issue, trying to decide on a radiator....HELP


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I need some advice on a radiator for my truck. I bought a cheap..er? ($180) stock replacement sized all aluminum radiator, and had a friend tig the inlet and outlet holes to the opposite sides to fit the chevys hose setup. The radiator does have the bulit in trans lines which I do not use. I have two electric fans that run constantly. Anyhow the truck worked fine in the winter and stayed around 160-190 where I wanted it, but now there has been some 50-60 degree days and the truck gets up to 200-220+ going down the highway and normal driving with a 160 thermostat. I know I can take the thermostat back out and it will help, but I am looking for a fix not a bandaid. So if you are still with me after that long intro here are my questions. 1) Has anybody used this radiator? http://store.summitracing.com/partdetail.asp?autofilter=1&part=BCI%2D60185&N=700+115&autoview=sku I know you get what you pay for, but for this price am I going to be completely satisfied? I am not a hardcore wheeler, but the truck will see alot of offroad time. 2) The truck has a normal bed on it, but I have thought about mounting a full size radiator in the back with big electric fans, but then would I need an electric high volume water pump and then am I going to overload my electrical system and eat up alternators, plus spend more money than the formentioned radiator and get the same results? 3) Does anyone have any other ideas, pictures, writeups anything that might help. Summer is right around the corner and I want to get this problem under control. Thanks in advance.

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Hood vents and/or bigger fans... :dunno: Just as a cheap 10min experiment you could make yourself some 1" spacers and put between the rear of the hood and the hinges, and see if that helps. Theoreticly it would give you more air flow trough the radiator and better cooling.

 

If it works you might wanna consider doing this: viewtopic.php?f=9&t=7696

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200 - 220 is about normal operating temp for a chevy v8. If you are gonna run a thermostat ditch the 160 degree and go back to the stock 195 degree. My truck runs about 200 -210 on average with the stock 2.8 radiator. It drops to about 195 or so on the highway.

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Yeah you told me that awhile back, and i cuss you for your good fortune...just kidding jamminz.gif ..or am I :headpop: I wish you lived closer, I would have you look at my setup and let me know what I'm doing wrong. Because I am correct in thinking an all aluminum radiator designed for a 4.0 has more cooling capacity than the 2.8 right? Could this aluminum radiator since it was on the cheaper side of the all aluminum radiator department just be a piece of junk? Also my chevy will fire right off just tapping the ignition when it is in the 160-180 range, but when it is 200+ is floods itself or vaporises(sp) the fuel and it cranks and cranks then sputters to life. It seems to like to run cooler I just can't keep the temps down. And that is with normal driving.

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What year V8 is in you truck? I know the newer ones do like to run cooler and the older ones are happier hot. I have an older V8 in mine. What size/ type of air box are you using? My truck showed some of the symptoms you are describing when it was hot. Turns out my airbox was too small.

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It is a mid 80s I think?, and I don't have an airbox just a small filter till I can find something better. The OEM style breather doesn't fit with my intake and distributer. My end goal is a snorkle but they are expensive and impossible to find used. This isnt a current picture but it is pretty much the same as it is now, except the new aluminum radiator took the place if the one that is in the picture.

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I think you just have to find the biggest, thickest (most rows) radiator you can -- and then say a few Hail Marys. Cooling is the major issue when doing a V8 conversion in an XJ or MJ. One of the guys up in Rhode Island had one he bought already converted. I don't remember what it had in it for a radiator. I do remember that it ran okay on the street, but on a trail ride he would have to stop and allow it to cool down about every 15 or 20 minutes.

 

I also think an equivalent size copper radiator will cool better than aluminum. Aluminum is preferred by racers because it's lighter, but copper conducts heat better than aluminum. Which means, if two radiators have equal surface (tube) area and equal fin area -- the copper one will cool better than the aluminum one.

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Swapping in a WJ steering gear will let you fit a large enough radiator for any of your needs.

 

Here's a link that talks about it, it is in a thread that is about a 5.3 swap and narrowing the nose. About half way down the page it covers the cooling system upgrades.

 

http://www.naxja.org/forum/showthread.php?t=946360&highlight=radiator&page=2

 

It will be a sweet rig when he is done.

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Swapping in a WJ steering gear will let you fit a large enough radiator for any of your needs.

How does using a WJ box create any more space?

 

I see the guy on NAXJA is using a WJ box. I didn't read the entire thread, so I didn't see why. It appears to be the same box, externally, as the XJ/MJ/ZJ/YJ/TJ box. The thing is, he's mounting it on a custom-built sub frame, and he specifically mentions that he set it pretty far back and intends to reverse it so the pitman arm faces forward.

 

I don't see this as offering anything to those who just want to drop in a V8 and not have it over heat.

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Swapping in a WJ steering gear will let you fit a large enough radiator for any of your needs.

How does using a WJ box create any more space?

 

I see the guy on NAXJA is using a WJ box. I didn't read the entire thread, so I didn't see why. It appears to be the same box, externally, as the XJ/MJ/ZJ/YJ/TJ box. The thing is, he's mounting it on a custom-built sub frame, and he specifically mentions that he set it pretty far back and intends to reverse it so the pitman arm faces forward.

 

I don't see this as offering anything to those who just want to drop in a V8 and not have it over heat.

 

 

A picture says a thousand words. I can tell you have never seen a WJ box....

 

 

 

Its totally different. It mounts above the frame leaving clearance for a full width radiator between the frame rails.

 

It that thread he is moving the axle forward far enough he is having the box rotation changed.

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That airfilter is way too small. Get one from a 84 buick lesabre or any 80'S V8 GM car with a large air box. It should fit over the distributor if that is a HEI. It took me a bit of looking but I used the stock air box bottom from the lesabre as stated but had to find a GM lid that was low profile enough to sit under the hood. The top ended up coming from a 77 Corvette but I have seen them on other vehicles. The engine builder at the racing shop I used to work at explained why the bigger air box was better but I forgot exactly what he said. My truck used to lurch a few times and stall in the middle of the road when it got hot. Switched airboxes to the larger one and haven't had a problem since. :smart: Trust me you will be happier.

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That airfilter is way too small. Get one from a 84 buick lesabre or any 80'S V8 GM car with a large air box. It should fit over the distributor if that is a HEI. It took me a bit of looking but I used the stock air box bottom from the lesabre as stated but had to find a GM lid that was low profile enough to sit under the hood. The top ended up coming from a 77 Corvette but I have seen them on other vehicles. The engine builder at the racing shop I used to work at explained why the bigger air box was better but I forgot exactly what he said. My truck used to lurch a few times and stall in the middle of the road when it got hot. Switched airboxes to the larger one and haven't had a problem since. :smart: Trust me you will be happier.

 

Do you happen to have a picture of the airbox setup, I'm not sure if I am looking up the right thing.

And I think the WJ steering box swap would be alittle more intensive then I want to go. I still drive this thing down the road and I don't want to be anymore of a hazard to other drivers than it already is. What is involved in moving the radiator to the bed? would I need a new water pump?

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I'm just going off of what i was told when i first started doin mine a couple years ago. have u made sure there arnt any bubbles in that upper rad. hose since its higher then the cap on the rad?

 

I have tried everything to make sure all the air was out including the bleed screw and steep inclines and declines. This is a slightly more recent view of the current cheapo aluminum radiator setup

 

 

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And I think the WJ steering box swap would be alittle more intensive then I want to go. I still drive this thing down the road and I don't want to be anymore of a hazard to other drivers than it already is. What is involved in moving the radiator to the bed? would I need a new water pump?

 

 

The WJ box is a more intensive swap but it will allow for a large enough radiator. Properly done it isn't a hazard to anyone.

 

For a rear mounted radiator you will need a large radiator a couple of Spal fans with a good shroud. An inline pump might also be needed to have enough coolant flow. It won't get much air flow on the highway unless you add a scoop or two to direct airflow to it. They will also be noisy on the trail when you are trying to listen to a spotter when the fans are running.

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This is the air cleaner on mine. It made a huge differance.

 

 

I think I would build an air box that seals to a cowl hood for cold air. I would add a vent on each side of the hood about 12" back from the front edge of the hood.

 

The radiator should also be sealed to the header so all the air must flow threw it. The factory splash shield under the engine or front skid plate should also be used since it creates a low pressure zone behind the radiator.

 

If a full length radiator is used the front crossmember should be modified to allow airfow threw it. The bumper should also be designed to do the same.

 

 

Here is a good bumper example that I built years ago that would work great but still neededd the front winch mount cut down to the fairlead size so it blocks less air.

 

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With the deer slayer added.

 

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It's now on JeepcoMJ's rig.

 

:cheers:

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You make a good point about the noise of the fans with a bed mounted radiator, I never thought about that. I have thought about making the air cleaner connect to the passenger side of the rear opening in my hood, but my concerns are rain or whater getting in, and the effects of high pressure low pressure of air moving over the hood at speed actually pulling air from the system. I have two electric fans that run constantly on the radiator right now. Do you think the summit radiator http://store.summitracing.com/partdetail.asp?autofilter=1&part=BCI%2D60088&N=700+4294924927+4294908280+4294908279+4294924500+4294839040+115&autoview=skuwould do the trick. I have the cash in hand to buy it, but for $499 I want to make sure all my research is done and it will work. It claims 350-400HP max and I'm not above that. If I knew of someone that could help me relocate a different steering pump I would probably go that route, but being as critical as it is I hate to mess with it too much.

 

actually it is this radiator but it doesn't say anything about the max horsepower? Inlet and outlet are wrong on the first one.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=BCI%2D60185&N=700+115&autoview=sku

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have you done a test to make sure your coolant temp sensor is working? also have to checked the volume and pressure of the water pump? it is possible they are faulty. if all checks out, have you though about running dual radiators? custom radiator? you may have to put another resivior that water runs through like after the t-stat and before the upper radiator fitting to increase the capacity of coolant.

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