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Topic: 78 L48 Thermostat?????160 or 180?

in Forum: C3 Cooling and Heating Systems


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78 L48 Thermostat?????160 or 180? (1/14)
 4/11/11 8:50pm
MK's78
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Dover, DE - USA

Vette(s):
1978 Silver Anniversary Corvette-White/Red 99% Original


Joined: 1/4/2009
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Would like to inquire about which thermostat to go with for my 78 L48? 160 or 180 ?????
 
 
mk's78
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78 L48 Thermostat?????160 or 180? (2/14)
 4/11/11 9:28pm
yostusota
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York, PA - USA

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1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top


Joined: 5/18/2010
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I have always used the 180 temp here in this area of the country..just flush out the system the best you can before you put it in..and be careful taking out the thermostat bolts..they can be a bit testy if they haven't been out before..

Rich

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78 L48 Thermostat?????160 or 180? (3/14)
 4/11/11 11:09pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


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I'd also go 180*. If your new t-stat has a small hole with a chunk of metal(restrictor) in it, take some side cutters, or something like that, to cut the chunk out, leaving just the small hole. The hole will allow you to fill the system much easier, plus the whole purpose of it is to allow a small amount of coolant circulation before the t-stat actually opens....this is a good thing!
If your t-stat does NOT have this hole, with the restrictor(chunk) in it, take a 1/8" drill bit, and drill a hole in the flat area of the t-stat, between the center, and the outer edge...this will accomplish the same thing.



Adams' Apple2011-04-11 20:16:18

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Joel Adams
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78 L48 Thermostat?????160 or 180? (4/14)
 4/12/11 8:11am
manchestersharkLifetime Member
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Equinunk, PA - USA

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1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.


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Smile  That's a NEW concept for me Joel!  Have not heard of that before. I am changing mine to 195, from 160.  Think it will run better, burn ALL the fuel, not push some of it through the system. I will check for the HOLE and plan accordingly.  THANKS   The new loomeum radiator should take care of MOST of the heat kept at bay.

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78 L48 Thermostat?????160 or 180? (5/14)
 4/12/11 8:16am
yostusota
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York, PA - USA

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1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top


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Mark it is used on most all new cars for some time now..it is a great way to avoid the almighty air pocket when you D and F the coolant..some even have a little pressed on check valve to keep the coolant or air from going back into the engine..not really needed on these cars since the thermostat points up.

Rich

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78 L48 Thermostat?????160 or 180? (6/14)
 4/12/11 9:45am
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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


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The temp rating of the t-stat is only for the opening temp, meaning, that's when the t-stat opens. It will not actually control how hot the engine runs...only the time it takes to get there.

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78 L48 Thermostat?????160 or 180? (7/14)
 4/13/11 8:46am
Gunslinger
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Frederick, MD - USA

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I would suggest buying a thermostat that has a fail-safe design...that if it goes bad, it will do so in the open position.  That will keep the engine from overheating in that event.  They're a bit more expensive but worth it.
78 L48 Thermostat?????160 or 180? (8/14)
 4/13/11 10:15am
Joker 1974
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Homer Glen, IL - USA

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What temp does vette run at now. When i drove my car daily in the summer i ran the 160 and in fall i put the 190 back in. Well what ever temp you go with I would suggest buying a thermostat that has a fail-safe design... Clown
78 L48 Thermostat?????160 or 180? (9/14)
 4/13/11 10:52am
yostusota
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York, PA - USA

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1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top


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Alright guys I'll bite..what brand of thermostat has a fail safe mode? Never seen or heard of one..

Ok I googled it quick ..doesn't look good..most of the posts about them look bad..like they stick shut..might not be a done design..neat concept though..I use the balanced ones..open and close when they are supposed to..the studies I found online show our old cars make more power with the 160' thermostat versus the 180.. but it wears the engine internals faster..not sure how but that's what I found..I think mine was a mr. Gasket brand..180'..

Richyostusota2011-04-13 08:11:37

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78 L48 Thermostat?????160 or 180? (10/14)
 4/13/11 1:13pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


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Doesn't really matter what the temp rating is...the engine is going to run hotter than that anyway. Otherwise, the thing would never open, or it would just sit there and go open/closed/open/closed/open/closed.
As I've said(and others too), the rating on the stat is OPENING temp. A 160* stat is gonna be open at 160*...a 180 will be open at 180...period. Having a 160 degree stat doesn't mean your engine will only run 160 degrees all the time...that's physically(and thermally) impossible. It just means the stat will open 20 degrees cooler than a 180 stat....that's it. The engine is still gonna continue to create heat. It's the job of the cooling system to control that heat...NOT the thermostat.
Around here, an engine with a functioning cooling system, with a 180 degree stat, will average around 200-210 degrees coolant temps, depending on the cooling system design. Installing a 160* stat will NOT lower that engine operating temp....but it will start coolant flowing thru the radiator sooner.



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78 L48 Thermostat?????160 or 180? (11/14)
 4/13/11 1:44pm
yostusota
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York, PA - USA

Vette(s):
1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top


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Posts: 1518

That's true about the temp thing Joel..but if your cooling system ie rad,fan is up to the task it should be able to dissipate the heat to make it run at the temp of the thermostat..I got a 180 and that's what the temp is at the t stat housing..+ - 5 degrees..but I don't live in an extreme hot climate..so I am sure that has a massive factor in it..there is only so much heat the air can absorb..I doubt there are many heat pumps for ac down there also!

Rich

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78 L48 Thermostat?????160 or 180? (12/14)
 4/13/11 2:44pm
manchestersharkLifetime Member
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Equinunk, PA - USA

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1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.


Joined: 10/31/2007
Posts: 2382

Smile I know that when I had the 195 in the old engine the gauge in the car showed bout 200. I put in a 165 and the gauge BARELY moved off the low end. Rebuilt engine, put in a new radiator, used 165, still held a LOW reading on the gauge. I have read and heard the becouse of the O.E.M. plane of the intake, duel plane, gas tends to stay liquid when cooler and does not burn well, resulting in evaperation rather than molecularization. Did you see that word RICH? Whew, hope i copied it right.Big smile Which leads to higher fuel consumption and less economy, mileage and power. HELP me out if I have been led astray. I'm willing to learn new tricks, I'm using this thing, and do what is right. Do not race cars run HOT for a reason? Was not the H.E.I. system created to make a HOTTER spark to aid in economy and mileage? I am going to try a 195 for a while to see what effect it has and compare.

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78 L48 Thermostat?????160 or 180? (13/14)
 4/13/11 2:55pm
yostusota
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York, PA - USA

Vette(s):
1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top


Joined: 5/18/2010
Posts: 1518

Mark you crack me up..you hit on a few fun points.. but I will make them all moot..since we drive cars with no computers to adjust for the million things that can be adjusted for there is no majic bullet..pop a Haltec on this thing and watch the hp fly off the charts consistently ..that's the word of the day..consistent ..one thing these cars will never be..NA carb cars are what they are..a constant test and tune..you can find a happy medium with them..but rarely are they at an optimum performance ..the thermostat is just a part of a puzzle that is always changing..oh and race cars are just that..run the 500 miles or so and then in the trash they go..did you notice that they lowered the pressure they could run at Daytona? So they would overheat in the draft to slow them down..it worked.

Rich

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78 L48 Thermostat?????160 or 180? (14/14)
 4/13/11 3:10pm
Gunslinger
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Frederick, MD - USA

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1969 convertible L71 427/435 4-speed black interior


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Posts: 3398

I don't think there's any ONE reason why GM went to HEI...or any manufacturer went to electronic ignitions.  I think the basic reasons were due to emissions requirements...a points and condenser system was simply unable to maintain emissions standards for the required mileage.  I believe the government standard was for the emissions system to last 50k miles, so a points system couldn't even last that long much less maintain its state of tune.  HEI could help ensure there was sufficient voltage to fire even very worn spark plugs where points, whether adjusted properly or not couldn't.  Timing remained unchanged with HEI where it couldn't with points that wear down.

While GM and others may have promoted HEI as for improved performance, blah, blah, blah...they had to come up with something to meet Federal emissions standards.  Regardless of the reasons, all manufacturers would have eventually gone to an electronic ignition system as standard simply due to advancing the technology, competition and performance anyway.  Government regs simply forced those advances before they may have occurred in a competitive market anyway.  Even then, the early HEI system had some issues and were modified before too long.

GM had a transistorized ignition for some years prior to HEI...the K66 in many Corvettes and other cars.  I remember the sales brochure for a '64 Pontiac Bonneville my Dad bought new showed transistorized ignition was a factory option for it.  I'm sure it must have been an option for other GM cars as well.  Whether that system was suitable for emissions controls is an open question...GM went with HEI rather than that system across the board.

 
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