primary cooling loop

[EBI-WPO]

Bob,
I guessed at a year, but the link below shows a bypass seat on this particular replacement thermostat. There were a lot of typical "regular" replacements listed without the seat. I imagine a lot of driveability problems are the result.

http://www.rockauto.com/catalog/moreinfo.php?pk=1349523

Terry

[Tom Reed]

Something like this will work too.

http://www.rockauto.com/catalog/moreinfo.php?pk=48822

[EBI-WPO]

Tom,
Exactly. In the design stage, you can build around an existing item, as I did with the Cummins 'stat. It also used an integral sealing ring around the large circumference, (same as your Pic!) which negated the need for a gasket, or any clearance for one. My design allowed the machined surfaces of my "housing" to mate tightly.

Use what you got.

The link I supplied for Bob was for a Honda Civic, as he said he used an existing, and adaptable housing from one that could be easily adapted to "projects". I guessed at the year and chose a 1983 1.5L.

Have fun,

Terry

[Tom Reed]

I have International SV engines in a few of my vehicles that use a similar t-stat. They have a nice cast housing that one  could easily make covers with an inlet and outlet, but they are a bit big for a 6/1. I did pursue this line of thought before deciding to try the valve on my engine. The valve to restrict intake flow has really worked very well in conjunction with the thermostat. It will now run at an even temp from stone cold up to full load at high ambient temps with the chp pump turned off with out any further adjustements.

[Ronmar]

A bypass thermostat or mixing thermostat would be the ideal for a large volume system.  I think they really work best with pumped systems as you need the pumping action to really circulate the coolant in the closed loop thru the cylinder, to get the thermostat to open and mix in coolant from the reservoir consistently.  All the V6 toyota's and the mitsu inline 4's use them as well...  Without some type bypass or secondary control, you will get "breathing"/"gulping" in a large volume/tank type cooling system, or large radiator without fan control(fan always running) till the supply temp warms sufficiently...

The taco pumps are not positive displacement(note the very low heads of 10'-12') so should run all day long deadheaded.  But it is easy enough to add a bypass valve from pump inlet to outlet.  A gate valve in this bypass loop also allows you to taylor the overall flow thru the system very precisely to your needs...  IE: close the gate valve just enough to deliver the desired flow to carry away max engine heat under most unfavorable cooling conditions...  For a 6/1 27GPM is WAAAAAY overkill:)  A taco 004 is a better option IMO...

The bleeder hole in the thermostat is good in that with a little head either from pump or created by thermosiphon, the general flow carries the warm water past the thermostat bulb so it opens in a timely manner...

[Tom Reed]

I concur with you Ronmar that additional pumping is a good idea with a bypass thermostat. That is part of the reason the idea was nixed for my 6/1.

[jcarpenter]

your making a bypass tstat system is great, and preferable to just about everything i can think of
if someone were to start manufacturing them, i bet he could sell more than a few!

Man, I sure wish I could buy an off-the-shelf Cummings T-stat assembly like EBI-WPO built.  Getting closer to implementing the water circulation system and the bypass port would take care of so many problems.  Think maybe I'll mosey by a junkyard or three and see what the Honda Civic T-stat assemblies look like.

Ah ... one other thing .... ran across a Grundfos Alpha pump and it just may be right-sized for this application.  Got to do more research......