Do you NEED a thermostat? - Page 2 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #16 (permalink)  
Old 10-21-2005, 01:49 AM
NorthStar's Avatar
Member
 
Last photo:
Join Date: Feb 2003
Location: Minnesota
Age: 51
Posts: 847
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I dont agree with the take the thermostat and coolant flows too fast to remove heat idea.
When the thermostat fails and is constantly open engine doesnt run too hot it runs to cold thats the same as taking thermstat out.

I think even wide open the thermostat is providing some restriction that creates a certain amount of pressure in block that is greater than the radiator cap which helps prevent steam pockets from forming.

I would always run a thermostat or at least a metered orifice like the circle track guys do.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 10-21-2005, 06:07 AM
Technical Support Barry Grant
 
Last photo:
Join Date: Jul 2003
Location: Dahlonega, GA
Posts: 1,503
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Greg Latvala
I dont agree with the take the thermostat and coolant flows too fast to remove heat idea.
When the thermostat fails and is constantly open engine doesnt run too hot it runs to cold thats the same as taking thermstat out.

I think even wide open the thermostat is providing some restriction that creates a certain amount of pressure in block that is greater than the radiator cap which helps prevent steam pockets from forming.

I would always run a thermostat or at least a metered orifice like the circle track guys do.

You said it yourself, even an open thermostat will have some restriction. From past expierence running with no thermostat, or restrictors my engines have run hotter.
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 10-21-2005, 07:38 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,023
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
Ding ding ding. The winner is Greg!

Here is an post from another site that I have read in the past. I wish I could take credit for it but I'm not that smart. hahaha



What some people will say in public. This is absolutely false, of course. Try to conceive of blowing on something hot, say a spoonful of soup, first slowly and then more rapidly. Which cools faster? For extra credit, try imagining the same spoon with first slow and then fast water moving across the bottom. Sheesh!

The issue with running without a thermostat is two-fold. The first part is that the thermostat provides drag on the water flow. This drag increases the backpressure the water pump and all of the enginesees. This additional pressure, over and above the nominal 15 psistatic pressure the radiator cap sets, raises the boiling point of the coolant. The reason this is important is that it suppresses localized film boiling at hot spots such as around the exhaust port. The transition from nucleatic boiling (bubbles of steam originating from irregularities on the surface) to film boiling (where the hot surface is coated with a film of steam) is called Departure from Nucleatic Boiling or DNB. DNB is very bad, for steam is a very good insulator compared to water. Once DNB occurs, the area under the steam gets hotter because the steam doesn't remove very much heat, adjacent metal which is still wetted heats from conduction. DNB happens there. The process spreads until substantially all the coolant-wetted surfaces are insulated by a film of steam. The engine overheats. In addition, the buildup in steam pressure forces the radiator cap open, bleeding coolant, therefore making the situation worse.

The second issue is that of water pump cavitation and surge. If the pump is operated at high RPM with insufficient head pressure(provided by the frictional losses in the coolant passages and the thermostat), there is a great likelihood that the pump will either cavitate (localized boiling and/or degassing on the impeller) or surge (an unstable flow regime). Either phenomena is destructive. Cavitation's collapsing bubbles act like little sand blaster, eroding away impeller material. Surge can do the same thing and in addition, can vibration stress the impeller enough to break it. Many times what looks like corrosion damage to the impeller, especially when the housing is damage-free, is actually cavitation damage.

The myth of velocity originated among those unschooled in physics or thermodynamics, I suppose, because a common racer "solution" is to press a fixed restriction into the thermostat housing neck when no thermostat is desired. The conventional (but wrong) wisdom is that the restriction "slows the water" as stated by the previous poster. In reality, all it does is provide some more dynamic pressure in the block by restricting the flow. The exact same result could be accomplished (assuming the water pump doesn't surge or cavitate) with a higher static pressure (cap pressure), assuming the system could withstand it.
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 10-21-2005, 08:50 AM
brainsboy's Avatar
brains
 
Last photo:
Join Date: Jan 2004
Location: tampa
Age: 42
Posts: 988
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Maybe Fords are different but I have never noticed any difference in Temp with or without a thermistat.

Just to add in, my current 408w runs the same with/wo one, and I custom lathed my own water pump pulley which is about 1/2 the diameter the stock one should be, so technically im turning even faster then most V8's. My purpose was to save 250$ on an SVO pulley set and all I had was 3.5" diameter stock to start with. Anyhow point and case, If this theory was true my case would of shown more of a difference then other V8's.

Perhaps its more related to motor design and water passage design then it is to just try and answer it by YES or No
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 10-21-2005, 09:38 AM
Member
 
Last photo:
Join Date: Aug 2003
Location: surrey bc canada
Age: 74
Posts: 646
Wiki Edits: 0

Thanks: 0
Thanked 10 Times in 10 Posts
thermestats

Quote:
Originally Posted by 454C10
Ding ding ding. The winner is Greg!

Here is an post from another site that I have read in the past. I wish I could take credit for it but I'm not that smart. hahaha



What some people will say in public. This is absolutely false, of course. Try to conceive of blowing on something hot, say a spoonful of soup, first slowly and then more rapidly. Which cools faster? For extra credit, try imagining the same spoon with first slow and then fast water moving across the bottom. Sheesh!

The issue with running without a thermostat is two-fold. The first part is that the thermostat provides drag on the water flow. This drag increases the backpressure the water pump and all of the enginesees. This additional pressure, over and above the nominal 15 psistatic pressure the radiator cap sets, raises the boiling point of the coolant. The reason this is important is that it suppresses localized film boiling at hot spots such as around the exhaust port. The transition from nucleatic boiling (bubbles of steam originating from irregularities on the surface) to film boiling (where the hot surface is coated with a film of steam) is called Departure from Nucleatic Boiling or DNB. DNB is very bad, for steam is a very good insulator compared to water. Once DNB occurs, the area under the steam gets hotter because the steam doesn't remove very much heat, adjacent metal which is still wetted heats from conduction. DNB happens there. The process spreads until substantially all the coolant-wetted surfaces are insulated by a film of steam. The engine overheats. In addition, the buildup in steam pressure forces the radiator cap open, bleeding coolant, therefore making the situation worse.

The second issue is that of water pump cavitation and surge. If the pump is operated at high RPM with insufficient head pressure(provided by the frictional losses in the coolant passages and the thermostat), there is a great likelihood that the pump will either cavitate (localized boiling and/or degassing on the impeller) or surge (an unstable flow regime). Either phenomena is destructive. Cavitation's collapsing bubbles act like little sand blaster, eroding away impeller material. Surge can do the same thing and in addition, can vibration stress the impeller enough to break it. Many times what looks like corrosion damage to the impeller, especially when the housing is damage-free, is actually cavitation damage.

The myth of velocity originated among those unschooled in physics or thermodynamics, I suppose, because a common racer "solution" is to press a fixed restriction into the thermostat housing neck when no thermostat is desired. The conventional (but wrong) wisdom is that the restriction "slows the water" as stated by the previous poster. In reality, all it does is provide some more dynamic pressure in the block by restricting the flow. The exact same result could be accomplished (assuming the water pump doesn't surge or cavitate) with a higher static pressure (cap pressure), assuming the system could withstand it.
well stated. i am amased at the miss info regarding cooling systems out ther.with no therm the by passis not functioning as desighned and in some systems this will cause over heat
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 10-21-2005, 06:28 PM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
http://www.stewartcomponents.com/tec...ech_Tips_3.htm
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 10-21-2005, 06:45 PM
Jake_Dragon's Avatar
Member
 

Last journal entry: New Carb
Last photo:
Join Date: Jul 2005
Location: Central Florida
Age: 49
Posts: 772
Wiki Edits: 0

Thanks: 2
Thanked 2 Times in 2 Posts
What about a nice high flow ball valve so you could restrict the flow?
I never liked the idea of a thermostat, but do like the restricter plate, but dont like taking my water neck off to change it.
Once you have it set where it works the best just take the handle off.

When I do run a thermostat I always drill some small holes in it to keep some water moving and avoid air in the system.
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 10-22-2005, 01:09 AM
Member
 
Join Date: Sep 2004
Location: WA.
Age: 58
Posts: 507
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Well, I am heading to Detroit to let all of those nice young automotive engineers know that they, along with all other automotive engineers, that thermostats never were necessary. The boss(es) is going to mad as hell about all of the research and developement that went into such a worthless item and then to think of the cost for supplying the item, installing the item, and warrantying the item.

I believe that some folks initially forget that,

1). Automobile manufacturers never ever include anything anywhere that aint necessary. Do you suppose those engineers overlooked the possibilty of putting a disc in there and drilling a hole?

2). To randomly remove components of a complete, engineered cooling system is in and of itself ignoring that engineering.
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 10-22-2005, 01:20 AM
New Member
 
Join Date: Jul 2005
Location: pennsylvania
Posts: 23
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
thermostat problem

i love all these answers yes you need a thermo or a restrictor try to keep temp at 180/200 what ever it takes less than 160 no good more than 220 no good less radiator no fan what ever!!! 190 is nice.
Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 10-22-2005, 08:50 AM
Member
 
Last photo:
Join Date: Feb 2005
Location: West Michigan
Posts: 307
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
You do need a thermostat to keep your engine at a minimum temp, and without one in the winter, you will freeze your a** off. I don't believe that your engine will run hotter without one. I think some of the overheating problems come from using a cooling system designed for 250 hp and trying to run 600 hp on the same cooling system. HP is energy, energy is heat. More hp and you need more cooling.
Bob
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 10-22-2005, 03:03 PM
Member
 
Last photo:
Join Date: Sep 2004
Location: wichita, KS
Age: 41
Posts: 126
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I will agree that all the things put on autos are there for a reason but sometimes that reason is void. such as a catalytic convertor, sure it helps with pollution but when you take it off you get a performance gain. same with smog controls. as for needing a thermostat for confort features like the heater, I dont need that cause I never drive it in the winter anyway. so I dont buy the because an engineer put it there it needs to be there.
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 10-22-2005, 05:24 PM
docvette's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Rebuild an alternator Last photo:
Join Date: Mar 2004
Location: Lafayette, california
Age: 62
Posts: 7,362
Wiki Edits: 12

Thanks: 0
Thanked 6 Times in 3 Posts
In the beginning...

Doc here,

In the beginning...There was Ford..Henry looked down upon his flock and said:
It was good..but shall be better..

The Model T had no thermostat in it..and a water jacket you could put your fist into..and a pump you could steer the QE II with...A big Brass radiator that ould stop a 30 cal bullet..freeze plugs that were doorknob sized...

what happened mostly on long hauls, traffic and hills? It blew steam and overheated max! because hot became hotter...and cold stayed that way for a long time! It was good enough for the day..but today doesn't cut it..It wasn't until they went to thermostats did it get better..(I have no idea what year that was..guessing 29 V8 60 flattie..)

Never knew the industry to manufacture and install ANYTHING they couldn't live without..to appease the Beancounters..

And Henry looked Upon his Factory..and it was good..on the 7 th day ... he invented the Car salesman...

Doc
__________________
Aftermarket Solutions
Electronic & Electrical
Innovations
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 10-23-2005, 07:19 AM
Member
 
Last photo:
Join Date: Feb 2005
Location: West Michigan
Posts: 307
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
And Henry looked Upon his Factory..and it was good..on the 7 th day ... he invented the Car salesman...
Reply With Quote Quick reply to this message
  #29 (permalink)  
Old 10-23-2005, 07:48 AM
Henry Highrise's Avatar
Lost in the 60's
 
Last wiki edit: Removing stuck fasteners Last photo:
Join Date: Dec 2001
Location: Dixieland
Age: 69
Posts: 15,189
Wiki Edits: 4

Thanks: 0
Thanked 11 Times in 10 Posts
Dat Doc aways tells it like it really is!
Reply With Quote Quick reply to this message
  #30 (permalink)  
Old 10-23-2005, 12:02 PM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by engineman
i love all these answers yes you need a thermo or a restrictor try to keep temp at 180/200 what ever it takes less than 160 no good more than 220 no good less radiator no fan what ever!!! 190 is nice.
With a restrictor your engine operating temperature will be all over the board. It will never stay anywhere close to constant day to day, week to week. A theremostat is the only answer.

If you have a cooling problem with a thermostat, then you have a radiator or airflow problem. period.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Whats the correct temperature my 350 should be running at? batman09 Engine 101 10-23-2005 12:29 PM
Adjustable Fan Thermostat Working in Reverse JohnTN Electrical 2 04-08-2005 11:43 AM
Electric fan thermostat Novaman78 Engine 4 01-27-2005 01:32 AM
Thermostat questions flyfisher Engine 5 09-29-2004 01:21 PM
thermostat crshrmn3 Engine 7 10-01-2003 06:27 PM


All times are GMT -6. The time now is 02:36 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.