TURBO-DIESEL-FREAK wrote:
joelukex4 wrote:
I thought it would go longer but everyone just gave up.
They gave up because they do not have reasonable arguments or speculation regarding these issues.
No, still here
TURBO-DIESEL-FREAK wrote:
3) If I were to go with a modified O.E. design, the machine shop would not guarantee the work, because they are cutting open and machining cheap castings, which were never designed to be used for that purpose. There is no possible way to make the modified O.E. thermostat housing even as strong as a stock O.E. thermostat assembly, let alone the Model 001s CNC machined housing and cap. I have some major concerns with that as it is going to be used in a heated and pressurized closed loop cooling system. The modified O.E. thermostat would therefore be sold with no guarantees whatsoever.
If you actually look at Kap's design, there are only 2 skinny 6mm studs holding the thing together, because there is only enough pot metal in 2 areas of the casting to take at the most a 6mm threaded hole. Kap's design also has no less than 2 gaskets in the housing, along with the O.E. thermostat-to-engine gasket, for a total of 3 gaskets... each of these gaskets are a weak link in the design. As an example of how cheap the O.E. thermostat assembly is was when I had to send an unfinished assembled Model 001 to a customer in an emergency because his CRDs thermostat not only failed, but the HOUSING CRACKED AT THE CRIMPED SEAM AND WAS LEAKING COOLANT.
Your assumptions are simply incorrect because they are based on a single proposal from Kap which was overly complex and not well thought out from a manufacturing or logistical perspective. Look at the solution proposed by Sargeindustries in this thread
viewtopic.php?f=5&t=83945His solution is elegant, cheap, extremely easy to manufacture and does not rely on 3rd party parts that might go out of production. It uses the same larger Hemi thermostat as you, relies on a single seal on the 'stat itself and I believe a temp sensor could easily be added. The refurbished housing, while admittedly not as robust as yours, is at least equal to or exceeds the OE housing in strength. I admit there would be some logistical challenges to overcome but I have priced it up and it would cost less that $100 to refurbish a housing and this is using a proto shop for the CNC work that is not the cheapest. This price point would permit a customer cost of around $200 which is below even what you originally estimated for the HDS when you started out a couple of years ago before the costs spiraled out of control.
As for your suggestion that the OE housing is weak, yes I have heard of a couple of instances of them leaking at the crimp plus some who reported they could rotate the 2 halves slightly. The one I took apart was solid at the crimp. This was another problem with Kap's modification as this weakness was preserved in his final product. This is the only "weak" part I've heard of and the Sargeindustries proposal completely overcomes this weakness.
TURBO-DIESEL-FREAK wrote:
Before the pollution control systems were installed on the V.M. Motori R425 and R428 engines, they were quite reliable engines in markets around the world with 100s of millions of miles driven on them. The R425 is still used as the engine of choice in the famous TX4 Taxi Cabs used in the U.K. If they had - as people claim here - "weak" cylinder heads, then that problem would have been solved years ago with updated cylinder heads even before we got the R428 here in North America.
The TX4 is actually quite a low volume production vehicle, less than the CRD. Admittedly the average mileage of a TX4 is probably a lot higher than the average CRD and the service has been a lot more severe. Maybe the reason that the "weak" cylinder head has not manifested itself in the TX4 is because
the owners are not interfering with the design and allow it run at the temperature the engineers intended? Maybe the cylinder head isn't "weak" at all but regardless, if running cool really is as problematic as you keep telling us over and over again would the TX4 have made it the distance it has?
TURBO-DIESEL-FREAK wrote:
The best reason I have seen for the low thermostat opening temperature is that it was probably mandated by the Environmental Protection Agency as a means of combating oxides of nitrogen pollution. Any self-respecting engineer worth his or her salt would not do this to a turbo-diesel engine unless they were forced to do so by political fiat or by the number-crunchers at head office to interfere with the engines reliability in order to make more money on servicing the engine.
In the mid 80's small diesels started to gain popularity due to preferential tax treatment on diesel fuel. By the mid '90's market share of new vehicles was approaching 50%. During that period emissions standards were not dictating the thermostat opening temperature. I invite you to go investigate what temperatures these engines were running at. You'll find that most were in the low to mid 80°C's i.e. closer to the CRD temperature than the 200°F+ you're suggesting "Any self-respecting engineer worth his or her salt" would use. Of course, I'm open to the suggestion that engineers back then simply didn't know what they were doing.