The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 03-16-2004, 02:24 PM   #1
lofat
Rollin' Member
 
lofat's Avatar
 
Join Date: May 2003
Location: Hayward, California
Posts: 240
Increased performance via thermostat

Changing out my thermostat really rocked my world.

Since I have had my truck I had never seen the temp gauge go above 1/4 way mark. I know it was running hotter than that, but it never over heated, and it never had any real problems as a result so I let it go.

because I don't like having 'wrong' info displayed to me, I decided to replace the thermostat and get a more accurate reading. well, I am not sure why, or how, but changing this part out has definitely improved my performance noticeably. seems like the lack of get up and go has got up and went.

when the beast is warmed up and I jump on the gas now, I notice that the acceleration is greater and where the transmission shifts out of first gear is different, like it is letting me squeeze get more RPM's out of 1st now.

I know little about carburetion, but learning as I go. but would this be the case of an electric choke reacting based on the engine temp? Besides changing the reading on my dash, how else does having the thermostat reading the correct information affect engine performance?

any insight shared is appreciated

Scott
__________________
:: 1977 C10 cheyenne ::
:: 1973 new yorker brougham :: for sale - $1,500

lofat productions
lofat is offline   Reply With Quote
Old 03-16-2004, 02:37 PM   #2
ocbaud
Garage Queen Material
 
Join Date: Oct 2002
Location: USA
Posts: 4,129
i'm wondering, what temp. thermostat should i get for mine engine?
ocbaud is offline   Reply With Quote
Old 03-16-2004, 03:24 PM   #3
lofat
Rollin' Member
 
lofat's Avatar
 
Join Date: May 2003
Location: Hayward, California
Posts: 240
i just got a stock AC Delco for my stock set up.
__________________
:: 1977 C10 cheyenne ::
:: 1973 new yorker brougham :: for sale - $1,500

lofat productions
lofat is offline   Reply With Quote
Old 03-16-2004, 03:42 PM   #4
76bonanza
Senior Member
 
76bonanza's Avatar
 
Join Date: Mar 2003
Location: St robert Mo
Posts: 2,001
as far as I know the electric choke does not operate on engine temp just air temp in engine compartment. Also the temp sending unit for the guage is in the block not the termostat. I would guess your thermostat was not letting the engine heat up enuf by staying open part way all the time. With the new one the engine is heating up to a better temp and running better as a result.

But then again I'm an idiot most of the time.
__________________
1968 c10
lowered 3" 4"
355/Th400 built by Hatfield racing in joplin MO
76bonanza is offline   Reply With Quote
Old 03-16-2004, 04:26 PM   #5
KShortell
Registered User
 
KShortell's Avatar
 
Join Date: Oct 2003
Location: Chesapeake, VA
Posts: 734
An engine that's too cool will tend to have less efficient combustion resulting in decreased fuel efficiency and carbon buildup. Exhaust emmisions will suffer, too. A stock small block thermostat application runs somewhere in the range of 185 to 195 deg. F. 1986 small blocks have a normal operating heat range of 185 to 205 deg. (per FSM).

Open system (raw water) cooled marine engines run lower temp thermostats (160 deg. or so) to avoid boiling salt (or even fresh) water in the system. However, closed systems (heat exchanger/coolant systems) use hotter thermostats since the system is under pressure and has coolant running through the block instead of raw water. As a result, these engines also tend to get an average 7-9% increase in fuel efficiency, not to mention longer engine life due to not having scale buildup in the jacket and heads.

I use a half-system-- the block is cooled by ethylene glycol coolant like in an automobile; the manifold is cooled by raw water. The idea is that a manifold is much, much cheaper and easier to replace than an engine!

HP and torque aren't really affected by this, it's mostly a driveability, longevity, and fuel economy issue...

The choke may have a preheat, but is actuated by air temperature, not coolant temperature.

Hope this helps...
KShortell is offline   Reply With Quote
Old 03-16-2004, 04:30 PM   #6
Lynx
Registered User
 
Lynx's Avatar
 
Join Date: Jun 2003
Location: Fort McMurray, Alberta, Canada
Posts: 513
There is a reason why its called "Operating Temperature" This is the temperature at which the engine preformes the best.

I noticed a bit of a diffrence when i changed mine as well... but mostly I was just happy i had heat!
__________________
Ben

1983 Silverado SWB 305
2002 Silverado Extended Cab 5.3
http://members.shaw.ca/bkennett
Lynx is offline   Reply With Quote
Old 03-16-2004, 05:56 PM   #7
lofat
Rollin' Member
 
lofat's Avatar
 
Join Date: May 2003
Location: Hayward, California
Posts: 240
awesome. thanks for the explanations! i am just stoked she is running better and thrilled to know a little more about how the cooling sys works.

now, here is hoping for the fuel economy to start kickin' in.

/me crosses fingers -
__________________
:: 1977 C10 cheyenne ::
:: 1973 new yorker brougham :: for sale - $1,500

lofat productions
lofat is offline   Reply With Quote
Old 03-16-2004, 07:44 PM   #8
bpmcgee
Registered User
 
bpmcgee's Avatar
 
Join Date: Mar 2003
Location: Northern Illinois
Posts: 2,181
Not sure I understand how changing the thermostat affected the gauge reading "wrong info." The gauge is driven from the temp sender on the side of the head. Did you change that too?

Brian
bpmcgee is offline   Reply With Quote
Old 03-16-2004, 09:13 PM   #9
lofat
Rollin' Member
 
lofat's Avatar
 
Join Date: May 2003
Location: Hayward, California
Posts: 240
nope i did not change that, but it is reading different now.

it actually goes beyond the 1/4 way mark. I am currently subscribing to the 76 Bonanza theory
Quote:
I would guess your thermostat was not letting the engine heat up enuf by staying open part way all the time. With the new one the engine is heating up to a better temp and running better as a result.
all i can say is that i made that change and i feel like the info i see more accurately reflects what is up with the engine.
__________________
:: 1977 C10 cheyenne ::
:: 1973 new yorker brougham :: for sale - $1,500

lofat productions
lofat is offline   Reply With Quote
Old 03-16-2004, 09:56 PM   #10
MylilBowTie
Right turn Clyde
 
MylilBowTie's Avatar
 
Join Date: Nov 2002
Location: Cincinnati, Ohio
Posts: 2,911
The thermostat may have gotten stuck in the open position and wouldn't let the engine heat up. When the thermostat was changed it is now heating up to operating temperature.
__________________
1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73
1992 Camaro RS 305 TBI
MylilBowTie is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 04:10 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com