engine overcooling

[comet2]

hi guys, been a long time since i last posted ! i have maybe a dumb question! on my 390 torino it  had a history of running hot on 85and up days so installed a stewart emp thermostat with bypass holes  i put the vacuum adv on full vac to cleanup idle problem solved ran best it has ever ran! then i installed  felony heads car still runs great noticeable power increase! but now runs to cool  it will warm to normal temp  and stay there while driving  30 mph stop and go stuff but any stretch without stopping it ends up cold idles like its cold stinks like bus garage! apparently people behind me dont like it! it has been a cold wet summer here in wny so i am relutant to change my set up for fear of  overheating in warm weather did the aluminum heads really suck this much heat out of the engine?

[jimeast]

What temp is the thermostat opening?  Can it be so simple (hopefully this easy) that you have a 160 deg thermostat and need a 180?

[steinauge]

You can always block a small portion of the radiator with cardboard and try it.If that cures your problem you will know where to go.

[comet2]

thanks guys , the stat is a 180 that i drilled two.078 holes  i tested it prior to installing. the stewart emps were 180 and 195 and have 3  .188 holes drilled in them worked great iron heads 88 degrees outside not good at 67 degrees!

[comet2]

i was thinking about blocking rad . maybe i can go back to a normal stat now i just cant wrap my brain around the heads dispersing that much heat! thanks again

[cjshaker]

Do you have a temp gauge with temperature markings? If you don't, then you're just guessing at the temp. Otherwise it sounds like you may just need to adjust your choke setting. Is it electric or thermally operated? If thermal, make sure the tube is actually good and drawing heat from its source. If electric, make sure it's not losing power somehow while driving. If it actually is running too cool, I'd step up to a higher thermostat, or one like you have only without drilling the holes. I would not block off your radiator because when you NEED that cooling, it won't be there.

[RJP]

thanks guys , the stat is a 180 that i drilled two.078 holes  i tested it prior to installing. the stewart emps were 180 and 195 and have 3  .188 holes drilled in them worked great iron heads 88 degrees outside not good at 67 degrees!

Why are you drilling holes in your thermostats?

[plovett]

I always drill one small hole in my thermostat and align it so it's at the top.  Now that I think about it, I think some thermostats come with a hole already there. I think it is supposed to help prevent an air pocket at the thermostat which could prevent the thermostat from opening.  Anyway, it's never once caused any problems for me. 

On the other hand a too cool thermostat is not a good idea, in my opinion.  A long time ago I was so afraid of detonation with my high compression engine that I thought I needed a 160 degree thermostat.   I have a decent cooling system so I was driving around with the engine too cool 90% of the time.  I always ended up with condensation in the oil.   It was hard to get the engine hot enough to evaporate all the moisture, most of the time. 

I finally switched to a 180 degree thermostat and have never had a problem since then.

180 degrees is the sweet spot for 99% of old school hot rod engines, in my opinion.  I know new cars run much hotter than that, but it hurts the power on our old school engines.  Okay, maybe 180-190 is okay.

paulie

[cjshaker]

I always drill a small hole in mine too. They all have a bleed hole for air, but they're so darn small that they take forever, if they bleed at all. But one small hole is sufficient. 3 is overkill and probably hurts the correct function of the thermostat.

[machoneman]

Yeah, three holes is too much. I also drill a small hole in mine ('70 351W 'Stang) for easy filling w/o trapping air. But, I'd do what was mentioned before and slap in a stock 180 'stat and give it a go. Noted too is that many modern 'stats do have a hole,many   covered by what I'll call a flapper valve. The cardboard trick will also work to show you what may be wrong.

[My427stang]

I agree, I drill one 1/8 hole and glue the stat in to make sure it stays at 12:00 to allow any trapped air/steam to pass quickly.  I have tried those Stewart stats and although they are high quality, they flow a ton of water at idle.  I'd almost bank on it being the stat

[unclewill]

I drill a series of small holes all the way around the thermostat so I don't need to clock it.  I don't mind having a bit of bypass when the thermostat is closed, but it is not my daily driver.  Over cooling is not an issue in the desert!

[comet2]

thanks guys  got a new 195 starts to open at 195 drilled 1 .062 hole in it installed had to help brother do water pump on  3.5 doch taurus  under timingchain cover really !!!! hope my ranger lasts 179000 it wont be mine then! well see what happens sunday!

[comet2]

ok, ran new thermostat today. little bit better but not what it should be. i think im gonna back the vacuum advance out  12+18+34 at idle down to 9+18+34 total i did find i am somewhat close on timing though  i needed gas asap had 10 bucks so put 87 octane in instead of 91 from 25mph roll 2nd gear acceleration  gave me preignition 3! rocks in a can! outsandingi never thought this engine could do that ! been running 22 years  and never could get it to ping on 89-93 octane sunoco at least i know my timing curve is close to optimum!!!

[Falcon67]

I drill 2~4 holes in the perimeter of any thermostat I use - 4 .125 holes are not going to pass so much water than the engine will run too cool.  Look at the size of the bypass hose on a SBF, that never closes - unlike a 351C. 

If you hear it rattling, it was detonating well before it reached your ears.  Best keep a close eye on the plugs, not a close ear.