Thermostat

[mhagie]

I have a copy of the engine used in Dr. Lees little red wagon in my 84 chev 4x4.
My question is what thermostat is recomended for my aplication?,this is a summer truck that is garaged in the winter
Is a 180 good enough or does it require a 195 for better performance?
I have the coolant drained now as I am playing with sending units to try and bring the factory temp gauge a little closer to reality.
I moved the oem sending unit to the top rear of the right cyl head and am using the oem location for my digital gauge.
With the order reversed I was with a 195 stat running 220-225 oem gauge 165 digital,
190 with thermometer in radiator fill neck.
As one can see neither gauge was close.
Confusing,huh?..............Merle

[gmctd]

The difference you're seeing, Merle, is coolant temp thru the block, pre-heads, vs coolant temp post-heads.

That's the problem with these indirect injection heads - the pre-cup arrangement shoves a lot of heat into the heads. A lot more so, than gasser heads.
Warm temps back of heads, higher temps front of heads.

That's why I suggest not running a coolant bypass from the back of the heads to the t-stat housing, thinking it will help cylinder-to-cylinder temp average.
It does that, but what about the heads? Hoo, boy!
Not in my engine!

If you're running long distance, heavy loads, I'd say the 195 stat would give you better efficiency and mileage.

Around town, the 180 may work better.

Hope this helps. And, glad to see you back on-line.

[CleviteKid]

If your entire cooling system is in good shape, you can use a 13 psi or 14 psi radiator cap, and the 195F thermostat, with a 50-50 mix of DexCool and distilled water.

If you have some pesky seepage (NOT from the water pump weep hole!) that you will get around to fixing "later" you may want to use a 7 psi radiator cap and the 180F thermostat, with a 33-67 mix of DexCool and distilled water (cheaper to keep the system topped off).

In reality, you probably would not see any measureable difference in fuel efficiency between the two thermostats. I run the 180F thermostat on the theory that I can get a slightly denser charge of air into the cooler block and head assembly.

Dr. Lee :cool:

PS: Say Merle, how many miles on your SAA engine now? I have just over 10,000 on mine, but that will change after driving to Montana and back this summer. It just keeps gettin' better and better . . .

[G. Gearloose]

Intersting. I observed a 370 series RS 180 open a full 1/2" at 185 degrees, much further than a fresh-from-the-box Delco 195 opens at 205, and opens no further. 3/8" inch max. pooeee.
I'd like to go back to 190-195 to check the milage thing but not until I find a tstat that opens fully within 10 degrees of its stamp.

If there's nothing there, i'd rather stop playing with them. Is the milage thing only applicable to the Ds4 trucks?

[gmctd]

Well, brightly shines the student, until...etc, etc.

Dr. Lee, Clevite Kid, and esteemed colleagues -

(that was the token respect offering, and may serve to ease me off the hook, later) ;)

As you all know, power, in the infernal combustion engine, is result of ingesting quantities of 20\80 air, using the 20% oxygen to burn stoichiometrically injected fuel, which superheats the remaining 80% to a high temperature, causing rapid expansion, creating high pressure which drives the pistons downward.

That's right, folks - you got a 6.5L hot air motor! Pneumatics is name of the game!

Chicago Pneumatic, Ingersoll Rand - eat your collective hearts out!
We got the power - we go the distance - ain't tied down to no steenkin' air hoses, neither!

A big ole air motor - kinda takes the wind outta your sails, don't it?
But, it does sound manly, right, massaging all that air!
And the smell of Diesel fuel - kinda makes my eyes water, at times.....
Ahem! Sorry - think I got something in my eye.

So (sniff!) - if it takes heat to make power, and we manly guys do lots of strange things to try to stuff more air in there, so we can add more fuel, to make even more heat, what happens if we divert some of that heat, say, to assist Mother Nature in warming an area immediatly surrounding the vehicle, no matter where we go, everywhere we go? As far as we go.

(That was the long, slow pitch - now for the fast curve!)

Running 195deg coolant draws less heat from the combustion event(s), which, over distances at hiway speeds, little or no stop-and-go scenarios, should, and seems to, offer better fuel-to-energy efficiency, resulting in better mileage.

Far as the engine goes, I don't think it cares which technology is feeding it - mechanical or EFI.

(To be continued..............)

This does not imply conflict with Dr. Lee's opening bid.
Cool, dense air is very...no, is highly...shall we say, extremely conducive to producing power.
More oxygen per unit volume is available in cool, dense air than in hot, expanded air.

Wanna prove\disprove it?
Take a clean, empty, paint thinner or equivalent sealable tin can outside on a warm-to-hot day.
Remove the cap and carefully fill the can with air.
Caution - try to get the cap on and sealed before any air overflows and spills out onto the ground. We don't want any ecological disaster over a simple experiment.

Now, take that can of hot air into the house, and see if you can sneak it into the fridge, without being observed. You may have to disguise it as a casserole, or something - be creative. She, who must be obeyed, can get very antsy over little things like this.
Note that the physical condition of the can has undergone no change since filling. Yet.

Later, for as long a duration as you're safely comfortable with, but more than 30 minutes, check the can, noting any differences in shape or form.
If it has some resemblance to that empy cardboard bath soap box you crumpled up and threw in the trash, then you've proved a volume of hot air occupies much less space when cooled.
And, that volume can now be filled wth more cool air .
More oxygen per unit volume of air.

If the can has not collapsed somewhat, then your fridge is probably on the blink, and you'll soon be dealing with she, who must....well, you get the drift. Prior disposal of the can is imperative.

Ford, Chrysler, GM-Isuzu, Cummins, Caterpillar, NavStar, Volvo, Benz, UD - all manufacturers of Diesel engines and Diesel-powered vehicles have added charge-air coolers to lower compressed air temps to ambiently cooler, more dense levels.

JOHN DEERE! ALLIS-CHALMERS!
Now stop that!
MASSEY FERGUSON!
Just ignore it INTERNATIONAL HARVESTER!- sometimes this computer seems to have a mind of it's own!
Besides, those tractors have all been hotrodded.

Not much way to cool the intake 'charge' in a naturally-aspirated Diesel engine, other than placing the intake duct in a cooler area, such as right at the front of the vehicle, where the forward motion also effects a mild ram-air charge.

(Note to self : plumb a pitot tube into that area to determine actual pressure available)

Will a 195deg t-stat improve fuel mileage? In theory, yes.

And, lest we forget - factory stock versions of Dr. Lee's truck - 6.2L n.a. EGR 700R4 swb 1500 kicked back 27mpg, off the showroom floor with 215deg t-stats, imsmc.
Later, some folks went to 195deg, others to 180deg. And, of course, fuel mileage fell, also.
And, none of those trucks were ever sold with more than a 20" 5-blade fan, nor were 20" fan upgrades avilable.
The auto trans cooler was in the radiator hot tank, engine oil cooler in the cool tank.

Of course, driver peace of mind, and not theory, will determine the final value.

And, I conclude.
Now, what say you?

[ 04-26-2004, 07:40 PM: Message edited by: gmctd ]

[mhagie]

Thanks guys I appreciate the comments.
IMHO taking the water temp from the head is the wrong place, placing the sensor that close to combustion don't make sense to me,thats why on all my small blocks I had a mechanical temp gauge connected in the intake manifold, sensing the temp as water leaves engine giving (to me) a more accurate overall engine temp.
I now have digital gauge in oem location If I'm not pleased with that location I'll move it to a tee at heater hose connection on crossover pipe.
Dr. Lee I am sad to say as of this posting I only have 45 miles on engine, I just did not get didly squat done last year.
I spent almost 2 months trying to find the knock in engine switching injectors, changing injectors till finaly the first of november I posted problem here and it was brought to my attention that maybe two injector lines were crossed and lo and behold thats what it was, #1 and #8 were crossed, Jamie was embarrassed of course.
Fixed that made one run 5 miles down the county road then the weather turned cold and I was done till now.
I really hate to get this truck finished cause then I don't know what I'd do for a hobby....Merle

[gmctd]

Merle, what's with the 190deg in the filler neck?
That's in the radiator cool tank - the fan should have pulled most heat out of the coolant.

I've plumbed the engine oil lines thru an external cooler, then thru the in-tank radiator cooler, with the temp probe where it comes out of the tank, and those temps seldom show above 140deg.

I plumbed it this way for winter temps stabilization, not wanting 40deg oil hitting the crank and mains with 180-200deg coolant temps in the block.
Seemed as though there could have been some distortion with that disparity in temps.

So - 190deg?

And, by the way, the 'tim the tool-man taylor' split in my personality has been temporararily assuaged, so I'm all better, now, and being serious.

[ 04-27-2004, 03:57 AM: Message edited by: gmctd ]

[britannic]

In the process of converting my milspec over to the Cummins, I noticed a big discrepancy between the amount of air the Dodge Ram core support will flow as opposed to my humble 1985 Chevy.

The only obstruction on the Ram is a triangular brace approx 5/8" in diameter. The core support allows the whole radiator to receive nearly all of the incoming air.

Therefore I'm incorporating the Ram's core support into the front of my truck to take advantage of this fact and allow me to use the stock Dodge radiator and intercooler in their original positions.

[CleviteKid]

Britannic,

Is there gonna be more than 100 pounds of Chevy left when you are done ? ? ? ?

The Clevite Kid ;)

[britannic]

I'm trying to work out what I should call it:

Dodgy
Chodgy
Dodgrolet
Chevrododge
...
...

:D :D :D

[CleviteKid]

How about this:

High Output Dodge Genuine Engine Posing as Ordinary Department-of-defense GI Equipment;

acronym: HODGEPODGE


The Clevite Kid aka TCK :cool:

[mhagie]

GMCTD,The point about 190 in filler neck was to state that it was the only gauge showing the correct temp,with it being on the cool side of rad 190 was about what I expected.
The other gauge locations however left a less than desireable result........merle

[britannic]

Love it - better than BodgedDodge :D !


Originally posted by CleviteKid:
How about this:

High Output Dodge Genuine Engine Posing as Ordinary Department-of-defense GI Equipment;

acronym: HODGEPODGE


The Clevite Kid aka TCK :cool:

[G. Gearloose]

Outstanding Acronym, we have a winner!

[Polar Diesel]

in my experiences the cooler the engine is the more power it produces. true for my old 6.2 and 6.5, this is after the cold advance is OFF. When the temp guage is on the first notch or so... I agree with CK

[gmctd]

Merle, what radiator do you have? 190deg on the cool tank was specifically my concern.
My cool tank never gets over 140deg, heat of summer, ac burning, towing a load in overdrive.

And that was with the stock 20" 5-blade, before I found and installed the 20" 7-blade GM made for Chrysler.

[mhagie]

GMCTD, The radiator is a Modine replacement for a 1980 HD454/400 to which I replaced the tanks with 6.2 tanks to get the oil cooler plus the tran cooler on proper side.
The 190 reading was taken with a small hand held digital thermometer about 2" into tank so temp drop at that spot would be minimal due to only catching about 1 tube and air flow at that point would be also minimal.
Fan clutch is a HD 6.2 Hayden unit, and at time of temp reading it was not engaged.
My contention is that IMHO where GM takes the temp readings is not relevent to the whole engine only on a basic spot barely above combustion, It is my belief that a temp reading taken from the cross-over pipe would be more accurate as to actual engine temp as a whole..........Merle

[wthif]

So after you tell me it shouldn't be a problem you change your mind. Looks like it is time to do some more modification. :D
Also if my recent coolant temps are any precursor to what I'll see this summer, something needs to be done. Got close to 230*w/ GM high flow 195* t-stat in the head with new setup, going up local hill, egt 700-800* (not bad). Previously with stock 6.2, 205* on same hill with 180* t-stat and 110gpm water pump, egt 1000*.



Originally posted by britannic:
In the process of converting my milspec over to the Cummins, I noticed a big discrepancy between the amount of air the Dodge Ram core support will flow as opposed to my humble 1985 Chevy.

The only obstruction on the Ram is a triangular brace approx 5/8" in diameter. The core support allows the whole radiator to receive nearly all of the incoming air.

Therefore I'm incorporating the Ram's core support into the front of my truck to take advantage of this fact and allow me to use the stock Dodge radiator and intercooler in their original positions.

[gmctd]

My truck was originally an '89 6.2L-J with T400, 3.25 final drive.
I installed new radiator, new oem water pump, RS 195deg t-stat, hoses, belts, green antifreeze. Later, Sept, new headgaskets, for leak at left rear block.

While driving, I observed the temp gage creep slowly up to 200deg, plummet back to 180deg, creep to 200, plummet to 180.
It performed this pattern till I parked it for the upgrade to 6.5L, Mar thru Oct 1999.

My concern was that coolant did not hold at some steady temperature, preferably around 200deg.
The plummet to 180 deg when the t-stat opened was evidence of cooling capability, as the transmission cooler was in the hot tank, and the engine oil cooler was in the cool tank. And, the non-valved heater circuit was from water crossover to cool tank.

Constant hot recirculation there, and thru coolant recirculation bypass from the t-stat housing to the water pump intake.
The t-stat did not have the bypass blockoff valve, as in the later engines.

Coolant temp locked in at 200deg in the 6.5l with the blockoff valve style t-stat.

But, when towing, I had temperature problems with the turbo 6.5L, even with the dual t-stat setup, before re-routing the trans cooler to external only, and the eng oil cooler to an external, then thru the heat exchanger in the radiator cool tank.

All is cool that ends cool, and late last year I found that Chrysler used a 20" 7-blade fan and AC Delco clutch, purchased from GM, on the '80s 440cuin New Yorkers and motor homes.

That fan cannot be found in the GM books, but Chrysler still offers it at around a hundred bucks.

That's my story, and I'm stickin' to it! ;)

[JeepSJ]

Originally posted by CleviteKid:
How about this:

High Output Dodge Genuine Engine Posing as Ordinary Department-of-defense GI Equipment;

acronym: HODGEPODGE


The Clevite Kid aka TCK :cool: Dang! And I thought I was clever with my Cracks Heads Every Valve Rattles Oil Leaks Every Time. I humbly bow to the master.