Cooling upgrade system.

[ari]

I received my cooling upgrade package or downgrade package depending on who you ask. I plan on installing it this weekend hopefully sooner if i have the time. The plan is before I install it I will take the truck for a long round trip drive and measure the temp the best I can across the block and heads and count how many times the fan comes on and for how long and repeat the exact same after install. I would really like to somehow hook up a flow meter to a radiator hose and see if there is a change. I will post the findings once complete.

 

[Action]

Someone should install clear tubes to watch the coolant flow with vs without the kit.

Again, does the number of fan cycles mean anything if we don't know what the coolant is doing at the sensor?

 

[SublimeMudTime]

Some auto mechanics have infrared cameras... Mine does. My boss also happens to have an iphone FLIR attachment I can get my hands on. If anyone wants testing done with those, get me a kit. I'll go through the work of getting before video with it heated up, and then after video with the kit installed....

 

[911joeblow]

Sorry all for not posting for a bit, I was in Germany for a week busy with other tasks. FYI we might be testing these with the military soon for possible deployment at least with the Army so these might be in larger scale production soon.

There has been a lot of back and forth on how the coolant flows in stock form and what changes occur after adding the kit. Even a nice diagram too!

So the diagram is correct in 2D form but what it lacks is the 3D vertical flow from the block up into the heads and back out the front of the heads. This has been discussed previously but I will try to reword it for perhaps more clarity.

Coolant enters the lower engine block at the front (having returned from the radiator). It flows around the cylinders toward the rear of the block. However the only exit path for the coolant flow is upward into the heads and then out at the front of the heads into the crossover and then thermostat and radiator. There is no restriction to the coolant flow from the point it enters the front of block to anywhere along the length of the heads. Because there is no specific path to follow the majority of the coolant enters the front of the block and then exits up to the heads before reaching the rear of the block and rear of the heads. Coolant is a good conductor of heat so even though the flow at the back of the block and heads is significantly less (no way to measure this specifically without lab grade instrumentation extensive block machine work and great cost) there is still conductivity into the general coolant flow but not at the level of the front.

This is a good time to add that coolant flows under two dynamics, push and pull or pressure and vacuum. If you tap into the system at the exit of the water pump you would see pressure, if you tap into the inlet you will see vacuum. This is not to be confused with overall coolant system pressure defined by the pressure cap at the overflow tank and overall system efficiency. In other words, in a closed loop system that is under say 15PSI there is still relative vacuum or relative pressure (push or pull if you prefer). This is important because in order to create flow at the back of the block I am adding a path to the vacuum side which draws stagnant coolant/air from the back of the block/heads to the front. That drawn out coolant is then replaced with coolant from the front of the block that has come in from the radiator. So we are not taking coolant from one end and sacrificing overall cooling as suggested we are only evening out the balance front to rear.

Another point brought up was overall cooling system temps and why I said it does not change significantly. Well again we are dealing with a closed loop system, simplified, a certain amount of heat is being produced by the combustion process and a certain amount is being released into the atmosphere by the radiator. In stock form more heat it transferred out of the front of the block and less from the rear. In modified form less is transferred from the front of the block than stock but more from the rear than stock. Overcooling is not desired nor is undercooling. By balancing the running temperatures we are improving efficiency of the both the front and rear of the engine.

Having pulled heads from many 6.2 and 6.5 blocks I have seen inefficient cold burn patterns on the front cylinders which show up as coking and carbon buildup. The rear cylinders show signs of overheating in the form of pitting, burned pistons, head gasket fire rings melted and head cracks etc. Years of engine failures recorded show consistent failures at the rear of the blocks both in the upper head/block as well as the bottom end.

In developing these kits I started with the foundation of knowledge that I have spoken of from motorsports as well as general knowledge from other manufacturers, engine builders and the military. I did not identify the problem, that had long been done before me. I am an engineer with many years in the industry and I do not simply accept what I get when it comes to cars and trucks and even lawn mowers and tractors. Yes I am that guy that has modified his lawn mower to gain efficiency. So when time is available (not often) I undertake projects like this one to see if there is room for improvement. This one started by me seeking out fixes that existed for this issue. I found the options others have mentioned that are available and even though the price was high I was not really concerned with that aspect as I know how little time I have and the relative cost of my time. The issue I had with the available options was with the execution of those kits. I could not see the full benefit of those kits without the heater circuit being open which is not great when you really want the system working in the summer. So I started working on a way to make a better set-up. My first kit was very basic. I installed large pipe fittings into the rear block off plates and drilled and tapped the crossover for a similarly large fitting. My initial thought was that I needed to be able to start off large and work my way down to a size that balanced the flow and temps without overcooling the rear and undercooling the front.

OK so lets talk DATA. Due to the lack of ability to directly measure the temperatures inside the block and heads I opted for a combination of VDO DTC thermistors in the front crossover and rear block off plate assemblies as well as FLUKE IR thermometer. I took temps with the system closed (no modification to the system other than the sensors) and temps after activating the system. I also took IR temps across the heads and block as well as spot readings at the crossover, thermostat, radiator inlets and outlets. Most of this testing was done with the truck in my shop (RPMs raised) and later during road testing which included a 5 mile long grade at full power all the way up. Front to rear block temps were between 30 and 50 degrees apart in the closed system with DTC and less with the external IR. Initial testing with the large orifice showed excessive reduction in the rear and increased temps in the front. Subsequent tests with smaller and smaller orifice sizes finally found the correct size for proper balance front to rear. DTC testing was by far the most accurate and repeatable. IR temps were the opposite as they were greatly affected by underhood temperatures, exhaust temps and other factors and as such carried little weight in the determination of the proper sizing. Further the factory temperature gauge consistently was incorrect and often to the tune of 40+deg off! I did create tables of this data but am not home and have no access to it while on the road. At no time did the system cause overall temperatures to increase or for any other detrimental factors. The ancillary data collected included fan cycle times, performance, and cabin temps. The fan cycle times were reduced between (from memory) 20% and 40% on average and the running time when on was also reduced though not a number I recall right now. In no small part due to the reduced fan cycle and run times the truck achieved higher speed and reduced time to climb the 5 miles grade each and every time. IR measurements inside the cabin showed temperatures at the engine cover and the center tunnel between the front seats reduced by 10deg+. Lastly there was a marked reduction in the temperature spikes indicated on the stock temperature gauge when transitioning from high speed highway and moderate speed secondary road speeds.

I encourage all kit purchasers to share your results good, bad, or otherwise. Make suggestions on how it or the instructions can be improved. Thanks!

 

[3jacks]

Pm sent

 

[911joeblow]

Minus the one kit to an APO, every order should have been received by now. If not send me a PM if you dont have tracking. Thanks!

 

[ari]

Ok I got the kit installed the results where unexpected. First off my rig has a 6.5 gep and a 3spd I installed the the kit per the instructions it was easy wont go into detail about it others have already. Here we go I went on a 10 mile loop there where 3 lights and speeds where mostly 45-55 the fan came on 6 times, when I got back I measured the temps with the truck idling I measured 203 on the rear and 207 on the front, both heads where where within + - 2 degrees the whole time including after install. With the truck idling I waited till the fan kicked on when it did the rear temp was 220 and the FRONT! yes towards the front of the truck the temp was 232!!!, when the fan turned off I read 202 rear 206 front and the temp slowly started climbing and the process repeated itself like clock work. After install the fan came on 4 times while driving. When I got back I measured 209 rear 212 front,I believe the higher temps where due to the engine warming up getting closer to the fan turning on. When the fan came on the rear was 220 and the front 226, the fan shut off when the temp was 202 rear 206 front and the process repeated itself. Even when I turned off the truck before and after install the front stayed warmer than the rear as the engine was cooling off. Now correct me if im wrong but shouldn't it be the other way around? either way the kit seems to do its job in balancing the temps 226 is way better then 232!!!. For fun I will run down to a parts store later and grab a new T stat and see what happens.

 

[911joeblow]

Thanks for the report Ari. Using IR temperature measuring I am not really surprised at all. So much of the surface temps are from residual heat under the hood which is why not much can be derived by IR unfortunately as it is not measuring coolant temps but external surfaces temps only. The reduced fan cycling is very good and indicative of the internal improvements. I'm glad the instal went smoothly.

 

[911joeblow]

Hey guys just a quick note. I have a couple of more kits ready to go before the next batch I can ship. After the 3rd it will be at least till the 15th before I can ship any more. Thanks for all the PMs.

 

[Sintorion]

I get the feeling that no matter what someone's test result that Joe is not going to be surprised by the result. My big, huge concern is that he has no idea where or how much coolant is flowing through his device. I would be seriously concerned if my fan kicked on less. That is a very good indication that you are back flowing coolant. Fan turning on less is not a good sign because heat has to go somewhere. Your radiator is where your cooling occurs. If your fan isn't turning on as much then you are not getting hot coolant through it and that heat has to be building up somewhere else. The lack of any factual data leaves all of this to speculation, but there is no speculating that heat doesn't just magically disappear. It has to go somewhere and no one knows where it is going.

The first test I would do if I had this would be to put check valves on the lines off the block to make sure that fluid can only flow in one direction from the rear to the front. I have a sneaking suspicion that with this device, that you are pulling hot coolant headed to the radiator and looping it into the rear of the block opposite of what you think is happening. This would make sense that your fan turns on less because you recirculating heat and it doesn't make it into the radiator to be blown off. That could also account for different temps in other areas. There has to be a reason that GM/AMG didn't see this as an easy solution, and I think these rudimentary test may give a good indication.

Also, having spent a lot, and I mean a lot of time in the world of govt contracting, I am very suspicious of his claim that he 'might' be showing this to the military. DoD procurement simply doesn't engage suppliers working out of their garage with shade tree solutions. Even if he was an 8a with a legitimate business it would be nearly impossible. Spend your money wisely my friends.

 

[dilvoy]

Sintorion,
The thing is, joe isn't the only one saying it's an issue. He's just saying he's got a different take on the solution for an apparent problem reported by people than what others have come up with.

What are your thoughts on the kits offered by Predator for $850? Or the Flash Off-Road kit for $345?

Not sure why you're expecting any sort of manufacturer/dealer level support on a piece of military surplus. AMG doesn't like dealing with non-government sales and has never been supportive of HMMWVs in private hands and, GM pretty much only wanted the Hummer brand for it's popularity and killed that off a while ago. TSB, recall, whatever... It isn't coming from AMG, GM, or anyone in any way shape or form for a truck discontinued more than a decade ago let alone one 20+ years old and sold as surplus. We're on our own to support these trucks.




Maybe they did want to address it but, couldn't because the end user (.gov) thought it could add an unnecessary failure point with not enough reward for the risk. Maybe, as I think I mentioned before, .gov didn't care about a small increase in reliability when they've got warehouses with so many BNIB and refurb engines in crates they sell them off surplus all the time. We just don't know what went on behind the scenes.

What we do know is that the original 6.5Ts had issues with #8 cylinder cracking due to poor cooling. To the point where engines were being replaced in H1s with no cost to the owners in many cases with no official TSB, recall, or otherwise. I remember the posts from the old HML days. The kits from places like Predator, Flash, and others were designed to address this. The 6.2s and the non-GEP 6.5s many of our trucks come with are of a block design similar to the original 6.5Ts and, while they don't see the temperatures turbo engines do, still have the same inherent cooling issue. Perhaps, like you mention, with the changes GEP made to the block, they DO have changes designed to reduce the problem internally that the previously mentioned engines don't. Admittedly, I don't know this and unless we had engineering drawings or could do a side-by-side teardown/cutaway it's hard to say.

Personally, $275 isn't that big a deal to me and spending it to take care of what is a known design flaw in my generation engine is okay by me. Especially compared to other solutions on the market for the same issue for $345, let alone $850.

As always, YMMV and my is worth exactly what you paid for it.

So what you DO know is that a small percentage of GM Turbo Engines had issues with #8 cylinder cracking do to poor cooling? If that were the case and not "The Queen of Cheap, General Motors" not designing it's block to withstand a certain amount of core shift during casting to not allow for thick enough cylinder thickness in the area of #8, why is it not found in the #7 Cylinder? Is it the Coriolis Effect working against the #8 Cylinder in the Northern Hemisphere and against the #7 Cylinder in the Southern Hemisphere, with so few Hummers being in the south that it was not noticed? This is a problem with the turbo block cast by General Motors. The 6.2's and N/A 6.5's and International and GEP Turbo Blocks don't have that cracking problem so who here has a Hummer with a GM Cast Block and is installing this kit?

 

[ryanruck]

So what you DO know is that a small percentage of GM Turbo Engines had issues with #8 cylinder cracking do to poor cooling? If that were the case and not "The Queen of Cheap, General Motors" not designing it's block to withstand a certain amount of core shift during casting to not allow for thick enough cylinder thickness in the area of #8, why is it not found in the #7 Cylinder? Is it the Coriolis Effect working against the #8 Cylinder in the Northern Hemisphere and against the #7 Cylinder in the Southern Hemisphere, with so few Hummers being in the south that it was not noticed? This is a problem with the turbo block cast by General Motors. The 6.2's and N/A 6.5's and International and GEP Turbo Blocks don't have that cracking problem so who here has a Hummer with a GM Cast Block and is installing this kit?

 

[Mario]

I get the feeling that no matter what someone's test result that Joe is not going to be surprised by the result. My big, huge concern is that he has no idea where or how much coolant is flowing through his device. I would be seriously concerned if my fan kicked on less. That is a very good indication that you are back flowing coolant. Fan turning on less is not a good sign because heat has to go somewhere. Your radiator is where your cooling occurs. If your fan isn't turning on as much then you are not getting hot coolant through it and that heat has to be building up somewhere else. The lack of any factual data leaves all of this to speculation, but there is no speculating that heat doesn't just magically disappear. It has to go somewhere and no one knows where it is going.

The first test I would do if I had this would be to put check valves on the lines off the block to make sure that fluid can only flow in one direction from the rear to the front. I have a sneaking suspicion that with this device, that you are pulling hot coolant headed to the radiator and looping it into the rear of the block opposite of what you think is happening. This would make sense that your fan turns on less because you recirculating heat and it doesn't make it into the radiator to be blown off. That could also account for different temps in other areas.

Fan turning less does NOT mean the fluids are not going thru the radiator unless temp sensor is in the radiator.
Fan turning on less means that the temperature thru temp sensor is either not flowing as much as before or that cooling is more efficient and temperature dropped and fan cooling isn't needed as much.

Sent from my SM-G955U using Tapatalk

 

[riderdan]

Having owned a number of... interesting... cars over the years that had forum followings, this not unusual. Someone thinks up a mod and starts selling it. Some owners install it. Those who have bought into it claim the mod makes the vehicle faster, quieter, more powerful. Those who haven't dispute this. Long tirades are written on both sides. No actual data is provided by the seller, the buyers, or the naysayers.

This could be the greatest thing since sliced bread. It could be a total waste of money. Without actual data, who knows? And I don't count "I think my fan came on less" or "I used an IR gun pointed randomly" as data. There are way too many variables to make those a useful indicator. To really tell you'd need before and after coolant temps taken from inside, in identical conditions (external temps, humidity, engine load, etc). Without this, it's all just speculation.

Note that I'm not saying this does or doesn't work. I'm saying we don't know.

 

[Sintorion]

Having owned a number of... interesting... cars over the years that had forum followings, this not unusual. Someone thinks up a mod and starts selling it. Some owners install it. Those who have bought into it claim the mod makes the vehicle faster, quieter, more powerful. Those who haven't dispute this. Long tirades are written on both sides. No actual data is provided by the seller, the buyers, or the naysayers.

This could be the greatest thing since sliced bread. It could be a total waste of money. Without actual data, who knows? And I don't count "I think my fan came on less" or "I used an IR gun pointed randomly" as data. There are way too many variables to make those a useful indicator. To really tell you'd need before and after coolant temps taken from inside, in identical conditions (external temps, humidity, engine load, etc). Without this, it's all just speculation.

Note that I'm not saying this does or doesn't work. I'm saying we don't know.

Totally agree and exactly what I have stated. We all want a magic bullet and guys like Billy Mayes made a fortune off of hawking products that fill that want. To get proper testing you would need access to a lab on the scale that no shade tree would have access too. Although I think a simple test that wouldn't cost anything would be to check the pressure at the back of the heads compared to where it taps in. If the pressure isn't greater at the heads, you are probably not going to get the flow he claims. I am guessing someone did that with the $850 contraption that has a proportioning valve.

And even if this product did work as designed, there is nothing saying that it will even address the problem with the cracking. Way to many 'what ifs' with a lot of 'maybes' and 'shoulds' for me to part with my hard earned cash to line someone else's pocket. Personally I think buying $275 worth of scratch off tickets would be a better risk of money.

 

[TOBASH]

 

[3jacks]

I bought one and it makes my hummer sexier and jump higher. I think I even look younger now and have lost some weight. The side effects are eye balls falling out, hair loss, hangnail and frequent urination.

Whats the the downside of this kit? Probably little to none. What's the upside? Maybe a little improvement...who knows. Small investment really so I'm putting one on.

 

[NormB]

View attachment 687631

I was just about to ask "where's that dratted popcorn emoticon when we really need it?"

Thanks, and "ditto that."

 

[ryanruck]

I guess some folks just like to

Again, this is not a new concept.

Nothing revolutionary.



But what do those amateurs at Edelbrock know?

Different engines. Different execution. Same concept.

This is no magic cure-all. Just the same type of small modification many folks have made to many types of engines over the years. Install one or don't. Lots of folks don't run a setup like that. Some do. S'all good by me.

Not getting why this is so difficult a concept to grasp.

Keep on keeping on though...

 

[dilvoy]

One guy had it figured out long long ago!