Radiator replacement problems... not cool!

[undy]

The LSC provided Griffin radiator (600hp rated) has never really seemed up to the task of keeping the big block cool. I went through numerous iterations, inlet shroud, HD fan w/shroud, upgraded electrical system (alternator, larger wires 'n relays); over-drive the water pump, water wetter and a 30% glycol mix. With every change I got a little closer to my goal, but not quite there. The latest and hopefully the last round was to get rid on the Flex-a-lite "Black Magic" fan (2000 cfm) and replace it with the Taurus 2 speed larger shrouded fan (4000+ cfm, apprx). I also did some additional research and found that Griffin made a "800 hp" rated radiator, the same 22" x 19" physical size as my "600 hp" rated one. It had dual 1 1/2" passes vs the 1 1/4" passes of the existing one. The radiator is 1/2" thicker, 3 1/2". I had them build the radiator w/o a filler tank this time, since I'm running an expansion tank on my 482" aluminum side oiler. I also got the Hollister dual sensor (180deg and 195deg) harness and relay setup to control both speeds. I spent yesterday morning pulling the cooling system apart to start the conversion. To my dismay, I found that evidently LCS has a "custom" radiator built for them by Griffin. The passenger's side lower water outlet is 3" higher up on the side tank to clear the steering rack than Griffin's standard bill-o-fare for the lower outlet. The outlet is directly behind the rack and is 100% inaccessible. I called a local custom speed shop that does extensive mig/tig work and they reported that they've had problems in the past modifying Griffins in such a fashion due to the epoxy sealer at the radiator end tube sheets. They ended up with non-repairable leaks. I've boxed it back up for shipping back to Griffin. I'll get on the horn with them tomorrow to see if they can do the mod ... or ... credit me and build another custom radiator, to the LSC's spec only with the 1 1/2" tubes. I hate losing the Cobra during prime time riding season...

When it comes to Cobras, it typically seems that no good deed goes unpunished...

Dave

[rustyBob]

I have never liked the fact that they rate them by horsepower rateing, they are a heat exchanger and should be rated by B.T.U.'s. I spent 10 years working in a nasty dirty smelly radiator shop and i have never heard of so many people haveing overheating problems or "cooling" problems in my whole time working at that shop as i have heard here on Club Cobra. Ihave built some big radiators and have heard of people that can't cool a small block Chevy with a radiator out of a Suburban........MAYBE it's not the radiator that's the problem.........under what conditions does the car run hot ...are you sitting still in traffic....running down the highway at 70 mph turning 4 grand on the tach.....a little info would go a long way on helping you solve your problem and MAYBE you wont have to throw a credit card at it to fix a problem that may not exist with the radiator.

[elmariachi]

Originally Posted by undy

The outlet is directly behind the rack and is 100% inaccessible. I called a local custom speed shop that does extensive mig/tig work and they reported that they've had problems in the past modifying Griffins in such a fashion due to the epoxy sealer at the radiator end tube sheets. Dave

Ughhhhh, that sucks! Hopefully they can mod it for you. Or surely there is a Tig artisan somewhere close to you that can. Hang in there Dave.

Jim

[vettestr]

Dave,
I feel your pain on this one ! If you run into trouble with Griffin not wanting too modify the radiator there is still hope. I have welded a radiator with the epoxy on the tubes myself. I had to add a port and it was epoxied. I rigged up a way to hold it in the needed position and I filled it with just enough water to cover the epoxy but left as much air as possible. I had to really throw the heat to it but no biggie, it worked.

[undy]

Originally Posted by rustyBob

I have never liked the fact that they rate them by horsepower rateing, they are a heat exchanger and should be rated by B.T.U.'s. I spent 10 years working in a nasty dirty smelly radiator shop and i have never heard of so many people haveing overheating problems or "cooling" problems in my whole time working at that shop as i have heard here on Club Cobra. Ihave built some big radiators and have heard of people that can't cool a small block Chevy with a radiator out of a Suburban........MAYBE it's not the radiator that's the problem.........under what conditions does the car run hot ...are you sitting still in traffic....running down the highway at 70 mph turning 4 grand on the tach.....a little info would go a long way on helping you solve your problem and MAYBE you wont have to throw a credit card at it to fix a problem that may not exist with the radiator.

Unfortunately, "horsepower" is sort of a universal rating system, one that the racing layperson understands. It's not exacting but it gets the concept across to the masses. If you rated in BTUs you'd have to have an accepted standard, @ a given engine temp, @ a given outside ambient temp and @ a rated CFM ... then you'd have to get it standardized in the industry .... not likely..

Our Cobras, by design, have small frontal areas and engine compartments. That's a recipe for overheating woes, more so than the "average" vehicle. The small frontal area severely limits the radiator core face area. (my actual core size is 18" x 17", about VW Scirroco size) Since you can't grow in size left to right or top to bottom that just leaves core thickness (wider cooling tubes) The tight engine bays (tighter with big blocks) makes it harder to get rid of the air too, once it's pulled through the radiator. I honestly feel that my existing radiator, coupled with the newer high CFM fan, will adequately cool my motor. The larger capacity radiator will give me a bit of much appreciated cooling redundancy. I really don't want to deal with this cooling issue again.

Originally Posted by elmariachi

Ughhhhh, that sucks! Hopefully they can mod it for you. Or surely there is a Tig artisan somewhere close to you that can. Hang in there Dave.

Jim

Ton's of good TIG/MIG guys around here.. It's dealing with the epoxy/leak issues that stymies everyone..

Originally Posted by vettestr

Dave,
I feel your pain on this one ! If you run into trouble with Griffin not wanting too modify the radiator there is still hope. I have welded a radiator with the epoxy on the tubes myself. I had to add a port and it was epoxied. I rigged up a way to hold it in the needed position and I filled it with just enough water to cover the epoxy but left as much air as possible. I had to really throw the heat to it but no biggie, it worked.

I HOPE Griffin is willing to do something!!!??? I plan on paying for the mods/new radiator anyway as Griffin didn't screw it up, just a little ignorance on my part. I'm holding off shipping it back to them until I can get them on the phone this AM. I don't want it to be on the way to them if they're unwilling to help me out.. It'll be off to Fleabay otherwise.. I'll do some more research today on acceptable ways to repair with that epoxy sealer.

Dave

[kitcarbp]

Hi Undy, I just finished my Griffin install and noticed your thread. The first rul of thumb is have maximum frontal area, followed then by going deeper (1.25 to 1.5 " tubes. If you are running a rad as small as 17" x 18" ( 306 sq in) you will struggle to cool anything over 400 hp even with 2 rows of 1.5" tubes for street duty, I would have expected them (Griffin) to give you better advice and inform you of the fan cfms you need. Hope is not lost in these cases because the solution is to "over-fan" the rad with very high cfms and a good shroud. BTW 2,000 cfm is for smaller hp engines, not our monsters. I threw my flexalite in the bin. Its an aftermarket joke. I mean you need 4,000+ cfm or more (like the Taurus fan), as long as your alt/harness is up to the job. I went the route of twin 13" SPAL fans to get ,max rad core area coverage. check my gallery for install pics. I am running a 16 x 26 core (for 416 sq in) with 1.25" tubes with about 450-475 hp in my application. My rough calcs. tell me I should be good to 550 hp (Griffin claims 600hp) but I will spend 1% of time at rated max power anyway. Engine compartment must be vented you're right, to avoid recycling the hot air. Are you using vac advance on your dist ? That will also help reduce engine temps. Good luck.

[undy]

Yep, I'm limited to a overall sized 22" x 19" radiator, by frontal frame design .... can't go larger (H x W) if I wanted to. My only possible radiator cooling "growth" was a thicker core and more CFMs, which I've done to the max.. Griffin rates "categories" of radiators by horsepower, 1" tube (400), 1 1/4" tube (600), 1 1/2" tube (800), 1 row, 2 row ...etc. If you have a 2 row 1 1/2" tube then it's 800 hp rated, no matter what the face measurements are.. It just gives a "ballpark" idea of what total heat rejection capacity it has. I knew all that going into it. (30+ years of mechanical engineering experience) My smaller core won't permit the use of 2 fans due to size constraints. You have 4" more radiator width that I do, a good thing ... for you. I'm running a Powermaster 140 amp 3 wire alternator with a #4 wire to my connection point and a #8 feeding the fan. I have enough amperage redundancy in my electrical system to pretty much handle anything I throw at it. The distributor's a MSD Pro-Billet, 100% centrifugal.. Changing it would be my last ditch effort. I really don't think I'll need to go there though...

Dave

Originally Posted by kitcarbp

Hi Undy, I just finished my Griffin install and noticed your thread. The first rul of thumb is have maximum frontal area, followed then by going deeper (1.25 to 1.5 " tubes. If you are running a rad as small as 17" x 18" ( 306 sq in) you will struggle to cool anything over 400 hp even with 2 rows of 1.5" tubes for street duty, I would have expected them (Griffin) to give you better advice and inform you of the fan cfms you need. Hope is not lost in these cases because the solution is to "over-fan" the rad with very high cfms and a good shroud. BTW 2,000 cfm is for smaller hp engines, not our monsters. I threw my flexalite in the bin. Its an aftermarket joke. I mean you need 4,000+ cfm or more (like the Taurus fan), as long as your alt/harness is up to the job. I went the route of twin 13" SPAL fans to get ,max rad core area coverage. check my gallery for install pics. I am running a 16 x 26 core (for 416 sq in) with 1.25" tubes with about 450-475 hp in my application. My rough calcs. tell me I should be good to 550 hp (Griffin claims 600hp) but I will spend 1% of time at rated max power anyway. Engine compartment must be vented you're right, to avoid recycling the hot air. Are you using vac advance on your dist ? That will also help reduce engine temps. Good luck.

[elmariachi]

Originally Posted by undy

I'm running a Powermaster 140 amp 3 wire alternator with a #4 wire to my connection point and a #8 feeding the fan. I have enough amperage redundancy in my electrical system to pretty much handle anything I throw at it. The distributor's a MSD Pro-Billet, 100% centrifugal.. Changing it would be my last ditch effort. I really don't think I'll need to go there though...Dave

You get the radiator issue resolved and I'll be my hat that your wiring and the Taurus fan handles the rest.

[Jerry Clayton]

the Lincoln fan flows much more cfm than the tauris fan

[undy]

Originally Posted by Jerry Clayton

the Lincoln fan flows much more cfm than the tauris fan

It's also an 18" fan vs a 17" fan too.. The fan's too big and so is the shroud, for my application. I was cosidering the Lincoln setup untill I had a chance to take some measurements. I hear it puts out around 5,000 CFMs or so..

[undy]

I finished the conversion yesterday and took a 100 mile jaunt today with it. All systems seem go. No overheating (Well.. it's 68 deg today). I fear I won't be able to put any heat on it till next season. What I'm seeing is good thus far though. The Hollister Taurus fan relay setup works great, The 180 sensor's in the manifold and the 195 sensor's in the bottom of the expansion tank.



I silver brazed a 3/8" FPT brass fitting in the bottom of the expansion tank for the 195 sensor.



Ive done the inlet shrouding. I just need to clean up some rough fabrication and polish everything.

As far as I'm concerned everything was a success.

Dave

[elmariachi]

Originally Posted by undy

I silver brazed a 3/8" FPT brass fitting in the bottom of the expansion tank for the 195 sensor.As far as I'm concerned everything was a success.Dave

Outstanding work Dave. Nice mod on the expansion tank too.

[bobcowan]

RustyBob might have a good point.

My engine is a small block 427, making well over 500hp. I use a standard Mustang replacement 2 core alum radiator, a 16" spal fan in a stock Mustang shroud, 180* high flow thermostat, and a mixture of 25% glycol and Water Wetter. Nothing fancy or special.

It'll get hot if i'm stuck on a lot of traffic on a hot day. We did the Cruise Colfax in Denver this year. We slowly moved west to east, all the way across denver on Colfax Ave. When we got to Aurora, we turned around and headed west. As we got half way back across town, we were stuck in traffic, light after light. Denver has no concept of traffic light synchronization. As we pulled in to the last stop, the engine was getting close to 220*. Not bad considering it took us more than 2 hours for the trip.

I track the car pretty regularly. Even when air temp runs about 100*, I don't have any trouble with engine heat; 20-25 minutes of high RPM use. Max water temp is right around 220*, oil temps a touch higher. After the cool down lap, water temp is almost to 180* by the time I shut it off.

On a cool or cold day on the freeway, I have trouble getting it up to operating temps. I'v had to block off the radiater with duct tape to get above 160*.

My cooling system is nothing special, just off the shelf parts. The radiator isn't even tunneled in like yours is. Your system is much more efficient than mine.

I would check timing - base and advance - and get it on the dyno to check fuel mixture. Those two simple things can really make it heat up.

[undy]

Originally Posted by bobcowan

RustyBob might have a good point.

My engine is a small block 427, making well over 500hp. I use a standard Mustang replacement 2 core alum radiator, a 16" spal fan in a stock Mustang shroud, 180* high flow thermostat, and a mixture of 25% glycol and Water Wetter. Nothing fancy or special.

It'll get hot if i'm stuck on a lot of traffic on a hot day. We did the Cruise Colfax in Denver this year. We slowly moved west to east, all the way across denver on Colfax Ave. When we got to Aurora, we turned around and headed west. As we got half way back across town, we were stuck in traffic, light after light. Denver has no concept of traffic light synchronization. As we pulled in to the last stop, the engine was getting close to 220*. Not bad considering it took us more than 2 hours for the trip.

I track the car pretty regularly. Even when air temp runs about 100*, I don't have any trouble with engine heat; 20-25 minutes of high RPM use. Max water temp is right around 220*, oil temps a touch higher. After the cool down lap, water temp is almost to 180* by the time I shut it off.

On a cool or cold day on the freeway, I have trouble getting it up to operating temps. I'v had to block off the radiater with duct tape to get above 160*.

My cooling system is nothing special, just off the shelf parts. The radiator isn't even tunneled in like yours is. Your system is much more efficient than mine.

I would check timing - base and advance - and get it on the dyno to check fuel mixture. Those two simple things can really make it heat up.

Base timing is 16 deg and total is 38, right where KC suggests. A/F is text-book, it was setup on a chassis dyno w/ a wide band O2 in a header bung. 12.5 @ WOT and 14.5 part throttle/idle.

What's the height and width of your radiator? That has a lot to do with it. LSCs use the smallest radiator that I know of, 22 x 19 (including the tanks).
I have to compensate with more width ( 2ea 1.5" tubes vs 2ea 1.25" tubes) to add capacity.

Lastly, FEs seem to produce more heat at idle than small blocks, more mass perhaps. At least that's been my experience.

BTW... with the fan on high I worry about sucking pets and small children into the front vortex created at the mouth of the car.. This thing does move some serious air though.

Nudder BTW.. After converting the 140 amp Powermaster alternator from a 1 wire to a 3 wire, at idle with the fan running it now puts out 14.2 volts versus the one wire's 13.6. This gives me a few more greatly appreciated cooling CFMs and a happier electrical system in general.

Dave