- Joined
- Sep 28, 2002
- Messages
- 39,799
On my never ending quest for complexity for no good darn reason, I acquired an inlet thermostat housing from Shannow. The price was right (shipping from Oz).
I like the idea of this. He was paraphrasing an engineering friend of his when he said that the outlet thermostat is the greatest way to warm your radiator to a desired temp.
I got lucky when I bought an aftermarket lower rad hose. You don't know how hard it is to cheaply change sizes on rad hoses. The OEM was tapered at the rad end and big from there to the suction side of the pump. The after market, luckily, just expanded at the pump and was perfect for inserting the thermostat housing by cutting out a bit of the middle. I wasn't going to spend the (near) $100 to make this work.
http://yfrog.com/6finletstatj (direct link)
Since the new housing takes the normal bypass flow, I capped off the normal return to the water pump.
http://yfrog.com/4oinletreturnstubbyj
I ran everything in line as it was before. The flow goes from the OEM thermostat housing (about 3 o'clock in lower image) to the heater core ..through the sandwich oil:coolant heat exchanger and ends up at the inlet thermostat housing. Currently, the OEM thermostat is still in place. It's the typical 195F. The inlet thermostat is a 160F. I didn't have the courage to start off with 180F or 170F while leaving the OEM in place. I don't always get the time to spend all day on R&D, so to speak, so I like to do things in a manner that allows them to function "as is" and fine tune later.
Stupid Is As Stupid Does
Well, I got the thermostat housing installed ..refilled the rad ..and started the engine. The thing is, I now had two closed thermostats at either end of the radiator. I didn't drill a weep hole in the lower thermostat ..and I surely had air in the engine. No bypass flow ..no thermal changes at the inlet stat ..even when the outlet stat opened and was begging for release.
I had thought of tee'ing the return initially and also wanted to be able to put this thing back to normal without too many hassles, so I just left the current hoses intact and capped off the tee like I did the normal return line. I initially broke this connection and filled the engine with a funnel on one end ..and just wait for it to seek its own level with the other. I ended up draining it anyway to put the weep hole in the lower stat.
[IMG=http://img231.imageshack.us/img231/2816/inletstat.jpg][/IMG]
[/URL]
Anyway, the 160F inlet stat is transparent at idle. My electric fan cycles normally. On the highway, if anything, this runs a tad cooler.
Shannow suggested going to a common supply and parallel returns instead of my inline setup. He feels that raw engine temp should control the inlet thermostat. I (up until he brought it up) merely looked at my heater core and oil cooler as one cooling circuit, which when taxed to a certain level, opened another cooling circuit.
Right now I've got a relatively long path to the return/inlet housing. Probably 15 feet. With using a common supply and parallel return, I'm uncertain how the flows will divide, but it would surely give the inlet thermostat unaltered temp to react to. Shannow recommended freeze plugs with holes drilled in them as a restrictor to bias the flow. I'm trying to pull a more elegant (that is, complex) way out of my behind for doing this.
Again, the setup works fine as is, but that may not be the case when I up the inlet temp to 170F and/or 180F.
I chose a NAPA Superstat for this initial run. I think I'll opt for a Robertshaw stat for the final temp once that's determined. It allegedly has more proportional flow than out run of the mill types.
Ultimately I would like to eliminate the OEM stat. It adds one more point for failure without assured quick diagnosis. OTOH, some have suggested that newer thermostats are designed to fail open. If that's truly the case (coincidentally, all of my stat failures for the past decade have been of the stuck open nature), then leaving the OEM stat in place can add some fail safe redundancy.
Yes. I never had to do this. I did it for the fun of it.
I like the idea of this. He was paraphrasing an engineering friend of his when he said that the outlet thermostat is the greatest way to warm your radiator to a desired temp.
I got lucky when I bought an aftermarket lower rad hose. You don't know how hard it is to cheaply change sizes on rad hoses. The OEM was tapered at the rad end and big from there to the suction side of the pump. The after market, luckily, just expanded at the pump and was perfect for inserting the thermostat housing by cutting out a bit of the middle. I wasn't going to spend the (near) $100 to make this work.
http://yfrog.com/6finletstatj (direct link)
Since the new housing takes the normal bypass flow, I capped off the normal return to the water pump.
http://yfrog.com/4oinletreturnstubbyj
I ran everything in line as it was before. The flow goes from the OEM thermostat housing (about 3 o'clock in lower image) to the heater core ..through the sandwich oil:coolant heat exchanger and ends up at the inlet thermostat housing. Currently, the OEM thermostat is still in place. It's the typical 195F. The inlet thermostat is a 160F. I didn't have the courage to start off with 180F or 170F while leaving the OEM in place. I don't always get the time to spend all day on R&D, so to speak, so I like to do things in a manner that allows them to function "as is" and fine tune later.
Stupid Is As Stupid Does
Well, I got the thermostat housing installed ..refilled the rad ..and started the engine. The thing is, I now had two closed thermostats at either end of the radiator. I didn't drill a weep hole in the lower thermostat ..and I surely had air in the engine. No bypass flow ..no thermal changes at the inlet stat ..even when the outlet stat opened and was begging for release.
I had thought of tee'ing the return initially and also wanted to be able to put this thing back to normal without too many hassles, so I just left the current hoses intact and capped off the tee like I did the normal return line. I initially broke this connection and filled the engine with a funnel on one end ..and just wait for it to seek its own level with the other. I ended up draining it anyway to put the weep hole in the lower stat.
[IMG=http://img231.imageshack.us/img231/2816/inletstat.jpg][/IMG]
Anyway, the 160F inlet stat is transparent at idle. My electric fan cycles normally. On the highway, if anything, this runs a tad cooler.
Shannow suggested going to a common supply and parallel returns instead of my inline setup. He feels that raw engine temp should control the inlet thermostat. I (up until he brought it up) merely looked at my heater core and oil cooler as one cooling circuit, which when taxed to a certain level, opened another cooling circuit.
Right now I've got a relatively long path to the return/inlet housing. Probably 15 feet. With using a common supply and parallel return, I'm uncertain how the flows will divide, but it would surely give the inlet thermostat unaltered temp to react to. Shannow recommended freeze plugs with holes drilled in them as a restrictor to bias the flow. I'm trying to pull a more elegant (that is, complex) way out of my behind for doing this.
Again, the setup works fine as is, but that may not be the case when I up the inlet temp to 170F and/or 180F.
I chose a NAPA Superstat for this initial run. I think I'll opt for a Robertshaw stat for the final temp once that's determined. It allegedly has more proportional flow than out run of the mill types.
Ultimately I would like to eliminate the OEM stat. It adds one more point for failure without assured quick diagnosis. OTOH, some have suggested that newer thermostats are designed to fail open. If that's truly the case (coincidentally, all of my stat failures for the past decade have been of the stuck open nature), then leaving the OEM stat in place can add some fail safe redundancy.
Yes. I never had to do this. I did it for the fun of it.