Changed thermostat from 160 to 195... need help re-adjusting

[haueter66]

I swapped thermostats on the advice of most everyone on this board.  Now my question is this:  Where should I start for re-tuning the engine?  It definately needs something because I had it perfect that it would start great cold or hot... now when hot it doesn't want to start as easy... I was thinking probably timing but wanted to check with the experts before I start messing around.

[dodge freak]

Well I am a new guy here but I been working on cars for 26 years and mopars for 15 of those and I think 180 is the hotest you should go. They only came out with 195 in the late 60's for emission standards and better gas milage. The hotter it is the leaner you can jet the carb. Yes some racers also claim you can get more power out the motor. I myself  use the 180 in the spring and fall and 160 in the summer. Some years I have left the 180 in all the time.  If you want to go with 195 you may have to get a heat insulator gasket for the carb. A cool can for the gas line might help to but you have to put ice in it all the time. What maybe happening if its a holley is the gas is coming out of the pump nozzles went the motors is off and flooding the motor, thats why its hard to start. I have seen racers drill a very small hole .020 in the mettering block behind the discharge line right above the power valve area. On the hp blocks you can thread a very small bleed in it. Almost like a air bleed, the pump still works fine but when its off nothing comes out of the nozzles. I wish I had a picture to show everbody. Good Luck

[Nacho-RT74]

on my 1974 Mopar catalog it says 195 degrees is the stock rate... I'm just posting what it says.

I won't say need adjust timming, but yes maybe mixture screws &/or metering rods to adjust mixture. Temp change it makes gases expasion

[haueter66]

Ok.  The only reason I went with 195 is because the local parts guru said since I have replaced the entire cooling system there is no need to run it cooler.  I changed out the 160 because I was told it allows build up inside the engine and that the engine will degrade faster.

I will try to lean it out a bit and see what happens.

[Rolling_Thunder]

ya - i need to put in the thermostat myself...   mine runs at about 150*-155*   

[is_it_EVER_done?]

You shouldn't need to do any adjustments, but you will probably need an insulating carb gasket to isolate the carb from the increased engine heat so that the fuel in the bowls doesn't vaporize out when the car is parked and hot. That is what causes harder starting when it's been sitting for awhile.

[haueter66]

Is that a fairly common item, the insulating carb gasket?

[dodge freak]

Call or go online at www.jegs.com or www. summitracing.com they have a bunch to chose from.

[RECHRGD]

My 440 runs best around 175/180.  At 195 I can feel a loss of power, pinging, etc..  I would put in a 180 t-stat and forget it.  Bob

[dodge freak]

I agree

[deputycrawford]

I would tend to agree with the 180 thermostat idea. Mine is a 180. I also had a problem with hot start issues. I put a insulating carb spacer on the intake and it helped. I also ran a fuel return line to the tank and it seems to have fixed it all together. I had a major problem with the fuel boiling out of the bowls of my Mighty Demon when hot. To see if a vapor problem exsists, just open the hood when you shut the car off hot. Come back in 20-30 minuntes and re-start. If It starts with no problem then you just have a heat soak problem and can fix it with a spacer.

[Chryco Psycho]

use a intake gasket with block crossover ports

[haueter66]

I think my intake gasket has the blocked ports.  I alraedy put the 195 in ... it doesn't seem to be running all that hot... maybe 1/8 inch past the lowest normal temp mark on the gauge.  I will try an insulating gasket and see where that puts me.  If I have to change out to a 180 I will...

[haueter66]

Can anyone tell me if there is an advantage to the open Phenolic spacer vs. the four hole?  Also, I run a carter afb on a mopar performance intake, so that would be a "square flange" correct?

Thanks for all the help!

[Chryco Psycho]

the 4 hole spacers help to increase carb signal on larger single plane intakes & with long duration low intake vacuum cams
open spacers increase the plenum volume for better high RPM performance but also allow some cross over on dual planes helping the top end of the dual plane intakes

[69chargeryeehaa]

i really think that a 160* stat is too cold, you need to maintain proper combustion temps and bring the engine to a high enough operating temp to keep the oil hot and get rid of moisture from the oil.  i read once that a engine (BB mopar) will actually last longer with a 195 stat than a 160 stat.  and wear on the hotter engine was actually less.  that being said i've tried a 160, 180 and 195 stat in my 69 charger 440, and the 195 seemed too hot, the 160 seemed too cold, but the 180 was juuuuust right.  with the 160 stat i found it ran too rich, never really got hot enough to burn all the fuel, and the 195 was ok, but too hot, just did'nt feel right.  with the 180 it seems perfect, and the plugs colored really nice, with all the carb adjustments like jets, metering rods and springs made the car runs like a dream,  actually i noticed that i picked up 3-5 psi of oil pressure at idle when going from the 195 to the 180 stat alone.  i too had hard start issues with a eddy intake and carter competition serries 750 afb carb, and i must admitt that the issue is still there with the 180 stat, but it's alot better than the 195, and now i barley notice it.  rant out.