primary cooling loop

[jcarpenter]

We've added a car radiator/fan to a 6/1 for the cooling system.  I wanted to add forced circulation to the beast.  Been looking at pictures and pump specs and I'm missing something here.  

The thermostat is a 180 degree unit so water will not be circulating until it opens.  Looking at the Taco 007 pump, it says the flow rate is 0 thru 23 gpm.  Does that mean I can have the pump on and "idling" at the lower input port until the thermostat opens?  Do I need some sort of safety bypass?  Are there some diagrams or explanations of this process somewhere?

Sure appreciate any guidance.

[Tom Reed]

I put a thermostatic snap switch on my pump. Now it turns on when the thermostat opens. See this thread http://www.microcogen.info/index.php?topic=2612.0

[jcarpenter]

I put a thermostatic snap switch on my pump. Now it turns on when the thermostat opens. See this thread http://www.microcogen.info/index.php?topic=2612.0

If there is ever a mismatch and the pump turns on before the thermostat opens, what can of damage could I expect?

[Jens]

If there is ever a mismatch and the pump turns on before the thermostat opens, what can of damage could I expect?

None, I ran somewhere around two thousand hours with a Taco pump that was driven off my generator - when the engine ran the pump ran.

Edit: I don't see a point of a snap switch for the pump - just one more thing to go wrong and pump power consumption is only around 40W.
Further, if you need to save 40W during the startup phase when the engine is cold you have more problems. With the pump cycling during normal operation (the thermostat cycles), you are just asking for issues. (IMHO)

[Tom Reed]

I believe the Taco 007 pumps can be "dead headed" with out issue. With the proper configuration the thermosiphon is extremely reliable. In fact after adding a thermostat to my system it would flow so much water that it would "gulp" cool water and repeatedly open and close the thermostat. Adding a valve to restrict the flow of intake water by about 85% got a steady stream of hot water coming out of the engine. My engine is used in a CHP system and the pump is used to circulate hot water from the engine through pipes in the floor of the house. There are a couple of thermometers in the system so I can see what's going on with the system.

[veggie]

If you drill a couple of 1/8" holes in the flange of the thermostat it will allow for minimal flow and prevent any "dead head" overheating of the pump.
In my system the pump runs full time and the cooling fan on the radiator is wired though an adjustable snap disc temp switch which senses radiator temp.
When the radiator reaches 175f the fan starts.

veggie

[XYZER]

About the only thing that would move me away from a thermosiphon system is if I had to mount the radiator lower than the cylinder or if using some sort of exchange system. As mentioned with the 1/8" hole(s) in the thermostat it will not open then close repeatadly (or gulp) until it steadly reaches operating temp. Let nature do the circulating...... Just suggesting .......

[Tom Reed]

Actually mine has 3 1/8" holes in the thermostat and still gulps. The valve solved it and surprisingly works well over a large range of operating conditions. In my case though there is a 35 gal reservoir of water, not a radiator.

[mobile_bob]

i don't have a 6/1 and never had one even in a movie, but

i use a bosch auxiliary heater pump from an old mercerdes to pump my coolant for the s195 changfa
it will support easily 15hp

drilled one 1/8" hole in the flange, and inserted a tiny cotter pin into the hole to keep it open, it wriggles around
and keeps from clogging that way.

it takes surprisingly little coolant flow for these small engine's, mine uses 5/8 heater hose and the smallest port going
into the cylinder from the pump is about 3/8" id

the bosch pumps are 12 volt if that is any help

mine runs any time the engine is running, and as others have done i use a temp switch to control the fan
using a 195 degree F Tstat and a 205 degree F fan switch, my coolant cycles between 205 and 215 degrees F
i also use a 7 lb radiator cap and 50/50 antifreeze coolant.

works very well indeed

bob g

[EBI-WPO]

Bob and all,
When I built the thermostat housing for cschuerms Listeroid Gen project (pics somewhere on the site), I utilized the dual seat thermostat from a 6BT cummins. The upper seat functions as a normal closed thermostat, and the lower is open, allowing bypass until warm. When the thermostat opens at temp, this closes the lower seat, closing off the bypass. Real popular in trucks and European cars this warms up easily, no rapid cycling, very even temps maintained no matter what is being used for/from the heatX.

I carved the housing in two parts from 6061 and used the Cummins Oring for sealing, and threaded ports for routing flow where needed.

Food for thought,

Terry

[mobile_bob]

Terry

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!

yes definitely food for thought, especially if one is connected to a rather large coolant tank.

only reason my works as well as it does is the system capacity is about 2 gallons, about a gallon in the engine
and another gallon in the radiator and plumbing combined.  the small flow via the hole in the tstat provides enough relief
and the system warm up time is very short, so i wouldn't probably go to the trouble to make up a bypass tstat housing
for my application.

i do however use a honda civic tstat housing, it basically is an extension housing that bolts to the cylinder head of the honda
and houses the tstat, it also has a bypass port, but i blocked it because it bypassed too much coolant back to the pump return side
probably because i had the wrong tstat in it!  maybe i need to check that out, it might do the bypass right if i had the right tstat in it.

i guess i never gave it much thought at the time,

its going to be a while before i can check out how it is configured, so i can't report for sure what it is.

if it works out to be such an animal, hmmm, the junkyards are full of these critters and they could be easily fitted to just about any engine
with little work.

thanks for the tip

bob g

[EBI-WPO]

Bob,
Its good conversing with you, I have been pretty busy, so just lurking mostly. An unexpected change in employement has upset things a little, but you know how that goes.

Just wanted to mention the bypass thing, as it seems that poking more holes in a thermostat seems to be the accepted alternative. Effective but hard to calibrate.

I'll bet the Honda thermostat had the bypass port valve on the bottom, but most replacement thermostats don't have them, so the bypass remains wide open. Used to have that happen with Audis & VW's.

Well, take care,
gotta get up early and I still have a few hours of stuff to do around the house.

Terry

[XYZER]

Actually mine has 3 1/8" holes in the thermostat and still gulps. The valve solved it and surprisingly works well over a large range of operating conditions. In my case though there is a 35 gal reservoir of water, not a radiator.

Interesting Tom....I have never even experimented with the drum method of cooling....although I have been tempted due to the simplicity....what size hose are you running?

[BruceM]

The bypass when closed thermostat sure seems like a nice solution, Terry. That would avoid localized hot spots around  cylinder head casting flaws, common on Listeroids.  I think I've seen a design years ago on the Lister Engine site where a small bypass channel was used, open all the time, to accomplish the same thing. What do you think of that approach?

I found I was thinking way too big on cooling for our CS/Listeroids... Someone here reported they were using 5/8" hose on a typical thermosiphon setup and still had ample capacity.  I found that even 6"x11" of radiator area with exhaust pipe induced draft airflow was more than adequate. Throttling flow because of oversized radiators and hoses on thermosiphons is often reported to avoid cold slug pulsing of the thermostat. 

[Tom Reed]

Dave, I'm running 1" hoses. I guess removing all that casting flash on the cooling water inlet was not a necessary "improvement". The way things are setup now, the temp of the incoming water to the hydronic system stays between 95 and 125f no load to full load and with the snap switch in the system only hot water gets pumped to the floors.

I like the thought that there is enough water in the system that a leak anywhere in the piping, except the lower hose will leave enough water in the tank to function in hopper cooled mode through the rest of the run. On the rare occasion that the heat is not needed the pump is switched off and the cover is removed from tank for evaporitive cooling. With the cover on no water needs to be added for most of the winter. The cover is some 2" Styrofoam left over from floor insulation. When the cover and pump are on almost no heat goes to the tank.