Summit Radiator

This seems to come up once a month or so. Chris, Luckypabst, probably wrote the best tech article about moving the passenger side valence support on the Pn Zone which is now lost to us.

This is not an attempt to redo that. This is just a bare bones "it fits and heres what you have to do."

The stock 230 radiator has trouble cooling most replacement engines. You basically have two choices once you have swapped engines. Get a 396 1967 Chevelle radiator or get a Summit aluminum one. Both cost about $180 to your door.
You will have to modify the Chevelle radiator with a grinder a little, but not that much.

The Summit, requires you to modify the front valence support of the M715. If you look at the passenger side radiator/valence support on your truck, you will see that it is tack welded to the valence and bolts to the frame at the bottom. You will also notice that there are two holes for a bolt to go through. The one being used and another one about 2" toward the radiator.

The entire plan is to cut that support out of your truck, cut off the hole used before, bolt it back in using the inboard hole and then reweld the valence to the support.

I did this in August 2005. I drove the truck into my shop with the stock radiator, used hand tools, die grinder with cut off blades and a mig, installed the Summit radiator and drove it back out of my shop in about 2-1/2 hours. This isn't brain surgery.

The radiator is Summit # SUM-380328.

Here are some pictures I took of mine last night. Look at the 3rd picture and you will see how the "inside" hole is now supporting my valence. Compare it to what a stock truck looks like and you will see what needs to be done.

Dang - I just ran across those pics and maybe even the whole writeup I did but with the jumble of boxes, I have no idea where it's at now.

Chris

Several more things.

My upper radiator hose blew on the way to the 2006 Texas FE. I had to have something right then in the small town we happened to be in. I bought a 1976 C10 350 upper radiator hose. One small cut and it fits great. The bottom I will look on to see if it has a number.

Something that really bothers me about the Summit radiator is the lack of a drain. I didn't trust my aluminum welding skills with a flux cored rod and a torch enough to burn up my new purchase, so I didn't add one. I would suggest anybody that gets one of these to have a machine shop add a drain if you can. It makes it so much easier to work on cooling stuff later on. My current method is to stick a hose through the cap and siphon out what is in there. Wait about 30 minutes for more coolant from the engine to get to the radiator and repeat the siphon. It works, but I have to plan ahead hours to get it low enough to pull the water pump without causing a flood.

Which will cool better? I am in need of doing something before summer gets here. 396 sounds simpler but still has top and bottom tanks and copper, old school. Summit you gain side tanks and aluminum radiator but might have electrolysis issues and need to move the support.

I've always read that a cross-flow is more efficient and it's what I plan on using when I get around to it. However the local radiator shop mentioned some issues using an aluminum radiator off-road and having them crack if mounted even somewhat rigid. His opinion was that a soldered steel and copper radiator is more durable without rethinking the mount system.

Chris

Tim, for a quick drain solution, you could splice into the lower radiator hose with a short piece of metal tubing with a valve of your choice. If you're having angle issues with the hose after the addition, it may even be easier to fab up a bent piece of tubing w/drain to both give you a drain and fix any fitment issues.

Do you have rubber pieces inside those brackets that hold the radiator tanks?
If so, that should solve most vibration/shock issues one might have with this style of radiator.

I have rubber on the bottom, but not the top.

You should put some in there.

I'm going to copy GM and have rubber isolators top and bottom.

I just picked up a small block chevy last weekend. As part of the deal I got a brand new Jeep CJ 4 core V8 conversion radiator. It is almost identical in size/shape as the stock m715 radiator. The mounting points are even in the same location. It looks like it will fit without modification. I don't know how well this will cool vs. the other radiators mentioned in this post. When I get home I can get a picture and part number if anyone is interested.

There is one Jeep radiator in a 2 core that will fit...upper hose connection is on the wrong side but a flex hose can be used there...doesnt cool as well as the stock 3 core but it works if one isnt low speed/high rpms for long periods.

There is another that can work...mounts need holes drilled, both hose locations are wrong and the drain valve is in the wrong place...this is a CJ radiator...3 core...I believe that is the Modine 583 type.

Other than that, I dont know of any Jeep ones that are close...if you have a different one than I described, it would be nice to know the application!!

The box of the radiator says it's from xtremeradiator.com. I looked it up on the website. I think this link will take you to it.

http://www.extremeradiator.com/store...spx?sku=583-4C

The one I have says it's for the CJ Chevy/Chrysler Conversion 583-4C. The dimensions are almost identical to the stock radiator. The width is about 1/4"-1/2" more narrow on the new radiator but I think with the slotted mounting holes on the radiator it would bolt in alright. The only significant difference I can see is the bottom radiator hose connection is about 4.5" closer horizontally to the center of the radiator. The vertical distance between the upper and the lower are both about 19". I haven't tried putting this in yet so I can't say for sure if it is truly a bolt in deal, but it looks like it to me. I hope this helps.

Looks like a 583 like I used....I had to modify mine by having the straps from the stock radiator put on in place of the ones that came on it as the supplied ones are angled on the radiator and the stock ones are straight...also moved both the upper and lower hoses on this one and the drain valve...hopefully yours is much easier to install...I see that the hose connections are correct for the 230 right off...wish I had found that a few years ago...

Guys,
My problem is when at a stop light or stop and go traffic my temp. goes up to above 205-210*. Not a huge problem for a short duration, but going 4 wheeling, I don't want to sit that high! No problems going down the road. Temp stays at 160*

Engine - 427 GM
Aluminium radiator - brand new
160* thermo
Flex fan - I don't think that is the best - also middle of fan is at bottom 2/3 of radiator

Any ideas an how to cool for the trail or in traffic. Or any other info needed

Thanks,
Dave

You need a shroud of some sorts to help the fan pull the air through while you are not moving.
When you are driving faster, it pushes the air through fine, but the fall isn't pulling enough while sitting still or going slow.

Might sound counterintuitive (and may well be wrong), but what about putting a 190* thermostat in? I've heard of this working in that the water stays in the radiator a bit longer to cool off more.

Does this fly with those who really know about this stuff (unlike me!)?

And yeah, a shroud will REALLY make a difference.

I think Tim's right on with the thermostat issue. I know I used to think the complete removal would be an improvement but was proven wrong way back when on whatever POS I was hacking on then. The water can move through so quickly as to not have enough time to cool off. That said, the lack of a shroud is probably the bigger culprit in this case.

Sounds like an airflow issue certainly but 160 is too cool. You'd be better off with a 180 thermostat.

Chris

I agree about the thermostate. I have a 10.25:1 compression 396 Big Block in mine. It did fine going down the road, but would shoot up anytime I slowed down. I started with a 160 t-stat and a 180 helped a lot. Then I added the Summit radiator and that pretty much stopped it. An Edelbrock water pump made it so when the engine was off for fuel stops or something and sitting there at 220 or so on the gauge it goes almost faster than I can watch it back to 180 as soon as I start up. The old water pump would only suck it down to 190 or so and then slowly work down to 185 once I got rolling. I am talking about 90-110 degree summer days.

Theoretically, if the engine cools above 35 miles per hour, the cooling system is fine. Not cooling below 35 mph is normally thought to be an air flow problem.

Try the thermostat first and then start looking for another fan. I have heard horror stories of those FlexFans coming apart and embedding themselves in people. An electric or solid mechanical fan with a fan clutch might be a better choice.

A fan shroud will always help. So says the man who hasn't built one for his truck yet.

Guys,
Thanks, I'll switch to the 190* even though that sounds crazy, but makes sense too! I think I'll try the electrical fan. I have tried a shroud but found with the flex fan the shroud sat half way down the radiator. Thanks again.

Dave

Electric fans come with their own shrouds, right? So you'll probably get better airflow than with the unshrouded fan you're running now.

Good luck! Let us know how it works out....

Ive got my 632 built and need some serious cooling setup to keep it cool in the hottest weather. got to figure which fuel injection setup to use along with what tranny? auto or standard? it should be around 800+ hp so it needs extreme duty parts.