![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
![]() |
#26 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,627
|
Re: Rebuilt Engine High Temp Issue
|
![]() |
![]() |
![]() |
#27 |
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
|
Re: Rebuilt Engine High Temp Issue
A 195 thermostat just makes sure the temp reaches 195 degrees before it opens and has nothing to do with cooling. If the water did stay in the radiator longer cooling it would also stay in the block longer heating. You need more water flow to cool not less. When I sit in front of a fan I turn it on high to cool me quicker not low. Why do you think they make high volume water pumps instead of low volume water pumps.
There is no magic here, it's all common sense. The more water flow and the more air flow, the more cooling. |
![]() |
![]() |
![]() |
#28 |
Registered User
Join Date: Dec 2007
Location: Santa Maria, Ca.
Posts: 1,423
|
Re: Rebuilt Engine High Temp Issue
__________________
69 Chevy 4x4 383 Power ![]() |
![]() |
![]() |
![]() |
#29 |
Registered User
Join Date: Dec 2007
Location: Santa Maria, Ca.
Posts: 1,423
|
Re: Rebuilt Engine High Temp Issue
There is no magic here, it's all common sense. Yes the slower a liquid runs across a surface the more heat will be pulled out of it. This is why radiators have so much contact surface
__________________
69 Chevy 4x4 383 Power ![]() |
![]() |
![]() |
![]() |
#30 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,647
|
Re: Rebuilt Engine High Temp Issue
Good advice above. My two cents -- dump the flex fan for sure. Even if it doesn't explode, it will not cool well enough. Your shroud should accommodate an 18" fan; get a 7-blade if you can, or a more common 6-blade. Assuming the fan has 2 1/2" pitch (it should), get a heavy duty thermal fan clutch. Install without a spacer; the fan should be halfway inside the shroud, or as much as nearly all the way in. And if you don't have one already, get a coolant recovery tank and a cap for a sealed system.
In case you need more info on different types of fan clutches: http://www.haydenauto.com/featured%2...s/content.aspx
__________________
- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
![]() |
![]() |
![]() |
#31 |
Senior Member
![]() Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,249
|
Re: Rebuilt Engine High Temp Issue
IMO you're mostly right. They can stick closed and that's trouble. I believe the original thermo. was 190 degrees. I was told that was for emissions. The old man sold me a 180 for my 72 and everything seems great. Don't recall what's in my 71.
Back to Cdowns point, is your fan shroud correct? Also check your mixture. Should be about -37F, which is half water & half coolant.
__________________
Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assembly kit for restoring the (a) truck from the ground up. My build thread, and more on the assembly kit https://67-72chevytrucks.com/vboard/...d.php?t=730025 |
![]() |
![]() |
![]() |
#32 | |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,627
|
Re: Rebuilt Engine High Temp Issue
Quote:
Does it ever close, even just a little bit? Does the thermo impede flow at all? Is there a pressure drop across the thermo? |
|
![]() |
![]() |
![]() |
#33 |
Registered User
![]() Join Date: Jan 2015
Location: West Haven, Utah
Posts: 135
|
Re: Rebuilt Engine High Temp Issue
Yep clutch fan seems like the way to go... at what temp does the clutch fully engage?
__________________
1970 C20 350/TH350, LB God Bless our Troops ![]() |
![]() |
![]() |
![]() |
#34 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,647
|
Re: Rebuilt Engine High Temp Issue
Per the above link: "Engages at about 170° radiator air temperature, (about 30° lower than coolant temperature)." So about 200* coolant temp.
__________________
- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
![]() |
![]() |
![]() |
#35 |
Registered User
Join Date: Jul 2010
Location: MD
Posts: 1,937
|
Re: Rebuilt Engine High Temp Issue
x3 (or whatever) on ditching the flex fan. Looks to be too far into the shroud too. Blades should be about a third way in to draw across widest area of rad as possible.
__________________
1969 c-10 Step Side Long Bed. I-6 250cid = ![]() |
![]() |
![]() |
![]() |
#36 | |
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
|
Re: Rebuilt Engine High Temp Issue
Quote:
To cool better you need more air through the radiator and more flow through the engine not less. Again why do you think they make high volume water pumps and not low volume water pumps? People need to quit spewing such false info, just because you read it on the internet doesn't make it true. To the OP get a good clutch fan, you will be surprised at how much more air it moves. Last edited by garyd1961; 08-30-2016 at 07:17 PM. |
|
![]() |
![]() |
![]() |
#37 |
Senior Member
![]() Join Date: Dec 2013
Location: Gods country East,Tn
Posts: 8,545
|
Re: Rebuilt Engine High Temp Issue
Pour some water wetter in it and watch the temp drop .
__________________
![]() 1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop |
![]() |
![]() |
![]() |
#38 |
Registered User
Join Date: Aug 2006
Location: Redmond, WA
Posts: 6,332
|
Re: Rebuilt Engine High Temp Issue
They didn't overheat when new. Run the factory parts and a 180 or 195 thermostat. That means get rid of the funky fan, get a stock one, with a good fan clutch, and make sure the fan is half-in/half-out of the shroud.
GaryD is right, the whole "slow the coolant down" thing is a myth, physics don't work that way. Or to sound like a beaker, "The thermodynamic transfer process operates at peak efficiency when the hottest coolant is exposed to the coldest air, which means keeping the coolant flowing as quickly as possible absent cavitation".
__________________
1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible |
![]() |
![]() |
![]() |
#39 |
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
|
Re: Rebuilt Engine High Temp Issue
One thing I would like to add that a lot of people overlook is airflow. You need water flow but also you need good airflow through the radiator. Radiators get clogged with debris such as bugs, dirt and weeds and need to be cleaned sometimes. I'm talking about the air passages. I usually just run a light spray from a garden hose through the air passages once in a while. Don't use a pressure washer or you might damage the radiator, it doesn't take a lot of pressure.
|
![]() |
![]() |
![]() |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|