BoarX wrote:
OK, slowly, but surely I am progressing with my quest to sort out thermostat issues on my CRD. Having original and functional OEM thermostat cracked open I have repeated my kitchen sink test to find that the main thermostat valve failed to fully close, letting through quite a flow of coolant through the radiator on the cold engine. Here is the proof:
https://drive.google.com/file/d/1AKkYjE ... sp=sharingSimple modification by deepening the hole in the housing which accepts thermostat plunger/piston results in this:
https://drive.google.com/file/d/1GZM-gm ... sp=sharingQuite a difference, n'est-ce pas? Closer look at the issue reveals the following: while most cars these days are using what are termed "thermostat inserts", some, mostly Audis, some Cadillacs and Saturns - and of course KJ CRD - use what are called "housing" thermostats. The former type are complete devices which simply need to be installed into the housing and sealed around the perimeter. Both the main valve and its seat are within the device and the valve closure is established during the assembly at the factory. All I have seen so far fully close the valve when cold. Here is an example:
https://www.amazon.com/dp/B000EQRH5G/re ... B000C9C00WThe latter (our) type relies on the housing to provide the stop for the piston, the seat for the valve and the attachment for the lower bracket holding the valve spring. Here is the typical one:
https://www.amazon.com/dp/B001FDWCWU/re ... B000C9F5TUMain advantage of the "housing thermostat" is substantially bigger valve diameter which could be as big as the housing permits. Thermostat "insert" fitted in that same diameter housing is going to have a valve roughly twice smaller in diameter - big difference in the coolant flow given the fact, that the amplitude of the piston motion is roughly the same. But that's where the advantages end. With "housing" type the housing becomes an integral part of the design and needs to be machined more precisely. In my case it was machined such that the valve failed to close. Just a little deepening of the piston guide hole in the housing resulted in almost complete seal despite being simply metal-to-metal.
The real question is, whether this is a feature or a flaw? As a feature it could be there to provide at least some minimal cooling in case the thermostat fails in the closed state. I recall reading about something similar on some Fords. As a flaw, well, the flaw is a flaw. Interestingly the mods by Kapalczinsky and TURBO-DIESEL-FREAK both used "insert" (and fully closing!) type thermostats to no ill effect, but did anyone do heavy towing with those? Also interestingly, the Chinese-sourced thermostat I currently have installed behaves in exactly the same way as OEM one - never closes fully. Was that a feature incorporated in the design given the difficulty of procuring and swapping the permanently sealed expensive unit? Somehow I am skeptical on that one ...
Well, now that my OEM unit is "fixed", all is left is to figure out how to reassemble the darn thing without the roll crimping. Wish me luck!
Cheers,
Alex
Lots to discuss here....
Your efforts to conduct experiments using boil testing without proper measuring equipment and a means to pressurize the liquid you are boiling is fraught with inaccuracies. Simple boil testing can only give you a very rough idea about what is happening and only approximately at what temperature it is happening at. Often thermostat valves do not fully stroke open until the temperature of the water they sit in is well above the boiling point. If you can not pressurize the water, you can not get the temperature up above 100 degrees Celsius. The Stant 48792 thermostat valve, (95 degree Celsius O.E. replacement Hemi engine valve), will not fully open until the coolant temperature is about 104.5 degrees Celsius. You also have to factor in your elevation from sea level, which will have a substantial effect on the boiling point of water. For example, I pulled the following from a GOOGLE search...
"For example, at sea level the atmospheric pressure is 760 mm Hg (also expressed as 760 torr, 101325 Pa, 101.3 kPa, 1013.25 mbar or 14.696 psi) and pure water boils at 100°C. However, in Calgary (approx. 1050m above sea level) the atmospheric pressure is approximately 670 mm Hg, and water boils at about 96.6°C."
How are you measuring movement of the valves? If simply by visual observation, it is difficult to see anything while observing in boiling water.
You claim that a thermostat valve designed for use in a stand-alone housing has the advantage of a much larger valve than a bare thermostat valve, (a ""insert" fitted in that same diameter housing"), and is therefore desirable because it allows for more coolant flow. You then write that the amplitude of the valves is the same. This is not an accurate statement and therefore untrue in many circumstances. A larger diameter valve does not always equate to more coolant flow; you have to account for the differences of total available stroke, (the "amplitude", as you call it), of the valve; they are most certainly not necessarily the same. There are also many variables in manufacturing thermostat valves and thermostat assemblies that you are not taking into account. Bare or stand-alone thermostat valves can have wide or narrow band flanges; two valves that have the same total diameter flanges can have different size valves inside those flanges, and therefore different total flow specifications.
The detailed specifications - including maximum stroke - for most thermostat valves can be obtained with some research and telephone calling to companies like Stant Corporation in Connersville, Indiana. This information is way more complete and accurate than can be obtained by boil testing at home. Boil testing is inaccurate, and only relevant for ballpark estimates of what is going on with the very valve you are experimenting with. Conclusions obtained by boil testing should not be considered for anything else.
A more accurate approach as to comparisons of thermostat valve coolant flows would be to consider the application of the valve... what engine is the valve designed for?
1) How large is the displacement of the engine?
2) The number of cylinders?
3) The size and weight of the engine block?
4) The state of tune of the engine? Compression ratio, cam timing, and whether or not the engine is boosted are all factors.
5) The type of fuel the engine uses?
All of the above would be factors that would have to be considered when the engineers design a cooling system; making sure that cooling system has the capacity and capability of cooling the engine in the most demanding situations. Designing the thermostat to provide enough coolant flow in the most demanding situations - whether it is a bare valve or a thermostat assembly - is one of those decisions that has to be made.
I can not speak directly to Mark Kapalczynski's Modified thermostat assembly in this regard, other than to say that re-using the O.E. thermostat housing has rather drastic limitations. It works, as can be witnessed to by people like papaindigo. I will state again for the record that it is the best modified O.E. design available, if you can still find the parts to put one together.
HOWEVER...
Does it work as well as the Hot Diesel Solutions Model 001? No; simply because of those limitations imposed by the re-using that O.E. housing. Kap's modified thermostat uses a valve meant for a 1995-99 Hyundai Accent 1.5L DOHC or SOHC. A 1.5L gasoline fueled, non-boosted four cylinder engine has a cooling system that is nowhere as robust as a 2.8L turbocharged four cylinder diesel engine weighing in at least twice as much and having the capability of towing a 5000 lb trailer, so I do not believe that Kap's Modified thermostat will have the coolant flow for heavy-duty use.
The Model 001, on the other hand, uses a thermostat valve that fits the entire line of Hemi V-8 engines, from the 5.7L naturally aspirated 375 horsepower engine to the 6.2L supercharged 707 horsepower Hellcat engine, (unsure if it applies also the 840 horsepower Demon engine). The Hemi engines weigh about the same as the R428 engine in the CRD, and produce WAAAY more power and torque. With all of this extra power comes extra heat production, and therefore the cooling systems of these engines are very robust and substantially larger with more cooling capacity than even a modified Liberty CRD engine cooling system - especially in pickup trucks with towing packages.
When designing the Model 001, getting the CRD engine up to a proper operating temperature was never our biggest concern. Our biggest worry was to make absolutely sure that the Model 001 would not contribute in any way to overheat situations. Designing and manufacturing a larger housing, and using the Hemi engine thermostat valves was the proper way to address such issues.
BoarX, you asked if anyone has towed anything heavy using the Model 001. Private message Mountainman. He has towed overcapacity trailers up mountain passes in his CRD with a Model 001 installed and he has had no overheat issues whatsoever. Private message bshooter as well; he has a highly modified CRD with a Model 001 installed that he goes mudbogging and rock climbing with. Again, no overheat issues with the Model 001.