What psi radiator cap - Page 3 - Yellow Bullet Forums
;

Go Back   Yellow Bullet Forums > Technical Section > Tech Questions - Monson Racing

Tech Questions - Monson Racing

Reply
 
Thread Tools Display Modes
Old 09-28-2019, 01:07 PM   #31
Topfun99
Senior Member
Smoked Another SBC
 
Topfun99's Avatar
 
Join Date: Mar 2009
Location: Temporarily Away, Check Back Later For Updates
Posts: 16,163
Default Re: What psi radiator cap

Quote:
Originally Posted by Coloradoracer View Post
I run a 16 lb cap and zero issues with copper gaskets. Have yet to have one leak...
I personally have no direct experience. I've just run across many comments from users of copper gaskets regarding water leaks.
__________________
Try not to take everything so literally. Just because someone suggests it's time to deal with the Elephant in the room doesn't mean you should break out the peanuts.

Thanks to:

HALTECH (Elite 2500 plus REM)
TRZ MOTORSPORTS
REAL STREET PERFORMANCE
FB PERFORMANCE
PTC
M/T Tires
Kris Starnes Racing

EMAIL - [email protected]
Topfun99 is online now   Reply With Quote
Sponsored Links
Advertisement
 
Old 09-28-2019, 01:10 PM   #32
Topfun99
Senior Member
Smoked Another SBC
 
Topfun99's Avatar
 
Join Date: Mar 2009
Location: Temporarily Away, Check Back Later For Updates
Posts: 16,163
Default Re: What psi radiator cap

Quote:
Originally Posted by boostedbowtie View Post
Is it normal to still have pressure in the system , even after sitting for 5 days or so ?

Started noticing this after putting a new cap on .

Its a 16lb lever style cap like this

Dave - When I had that happen to me on my car it was the result of water reacting with the system metals. Let's put it this way, I've never had that happen when my car had anti-freeze in the cooling system.
__________________
Try not to take everything so literally. Just because someone suggests it's time to deal with the Elephant in the room doesn't mean you should break out the peanuts.

Thanks to:

HALTECH (Elite 2500 plus REM)
TRZ MOTORSPORTS
REAL STREET PERFORMANCE
FB PERFORMANCE
PTC
M/T Tires
Kris Starnes Racing

EMAIL - [email protected]
Topfun99 is online now   Reply With Quote
Old 09-30-2019, 07:41 PM   #33
1leg
Member
Pullin gears
 
1leg's Avatar
 
Join Date: Jul 2011
Location: Escondido
Posts: 700
Garage
Default Re: What psi radiator cap

Quote:
Originally Posted by Topfun99 View Post
Dave - When I had that happen to me on my car it was the result of water reacting with the system metals. Let's put it this way, I've never had that happen when my car had anti-freeze in the cooling system.
This is correct. you are likly having a chemical reaction with something in your coolanat system. Complety drain and flush and just use plain water(if you have good local water) and a little bit of coolant.

https://www.aa1car.com/library/cooli..._corrosion.htm
1leg is offline   Reply With Quote
Old 10-01-2019, 01:24 AM   #34
MN Hemi
The Phantom Machinist
Smoked another BBC
 
MN Hemi's Avatar
 
Join Date: Dec 2014
Location: I’m retiring this fall
Posts: 1,881
Default Re: What psi radiator cap

Depends on the head gasket too. If youíre using copper head gaskets, keep it at or under 8#. They can weep otherwise. The cylinders seal up fine, but the water can weep.

On everything else I run, I use a 16# cap with no problems.
__________________

The Phantom Machinist
MN Hemi is offline   Reply With Quote
Old 10-01-2019, 01:33 AM   #35
MN Hemi
The Phantom Machinist
Smoked another BBC
 
MN Hemi's Avatar
 
Join Date: Dec 2014
Location: I’m retiring this fall
Posts: 1,881
Default Re: What psi radiator cap

Quote:
Originally Posted by Kane View Post
Why the lower pressure for copper gaskets??
What Iíve seen is, with copper and o rings, the cylinder gets good pressure to seal, but the water jackets can weep.
The problem is a little more common with aluminum blocks. The sleeves generally are .004Ē proud on the deck and reduces the clamping force around the water jacket. Also, many times the factory surface on the block before the sleeves go in is less than perfect, and then distorts a little from the press fit. They are always much nicer when we're able to correct the deck nice and then install the sleeves.

On my Mitchell X block, it will weep a little bit when it first goes in the car after freshen. Quits leaking after a few heat cycles and I also add a sealant tablet to the system. Itís not much, like a little drip on a corner or something, and then none. I use an 8# cap.

Iron blocks with a good finish are way less likely to leak, but being copper is dead soft, it will give over time. They can develop a leak with a high pressure cap occasionally.
__________________

The Phantom Machinist
MN Hemi is offline   Reply With Quote
Old 10-11-2019, 03:36 PM   #36
blackmagicturbo
Member
Pullin gears
 
blackmagicturbo's Avatar
 
Join Date: Jul 2010
Location: ventura ,ca
Posts: 500
Garage
Default Re: What psi radiator cap

The fastest 4.6 modular engine builder in the world told me that you want higher pressure to push water to the metal surfaces of the engine under power, so there is no steam. i run a 30+ pound cap.
__________________
blackmagicturbo is offline   Reply With Quote
Old 10-11-2019, 05:46 PM   #37
brmustang
Senior Member
Smoked another BBC
 
Join Date: Feb 2010
Location: Arkansas
Posts: 1,753
Default Re: What psi radiator cap

Quote:
Originally Posted by boostedbowtie View Post
Is it normal to still have pressure in the system , even after sitting for 5 days or so ?

Started noticing this after putting a new cap on .

Its a 16lb lever style cap like this

Do you think it’s possible it is creating a vacuum as it cools down?

Last edited by brmustang; 10-11-2019 at 05:47 PM.
brmustang is offline   Reply With Quote
Old 10-12-2019, 03:00 PM   #38
Topfun99
Senior Member
Smoked Another SBC
 
Topfun99's Avatar
 
Join Date: Mar 2009
Location: Temporarily Away, Check Back Later For Updates
Posts: 16,163
Default Re: What psi radiator cap

Quote:
Originally Posted by blackmagicturbo View Post
The fastest 4.6 modular engine builder in the world told me that you want higher pressure to push water to the metal surfaces of the engine under power, so there is no steam. i run a 30+ pound cap.
That's a funny way to say "higher pressure raises the boiling point temperature".
__________________
Try not to take everything so literally. Just because someone suggests it's time to deal with the Elephant in the room doesn't mean you should break out the peanuts.

Thanks to:

HALTECH (Elite 2500 plus REM)
TRZ MOTORSPORTS
REAL STREET PERFORMANCE
FB PERFORMANCE
PTC
M/T Tires
Kris Starnes Racing

EMAIL - [email protected]
Topfun99 is online now   Reply With Quote
Old 10-12-2019, 03:03 PM   #39
Topfun99
Senior Member
Smoked Another SBC
 
Topfun99's Avatar
 
Join Date: Mar 2009
Location: Temporarily Away, Check Back Later For Updates
Posts: 16,163
Default Re: What psi radiator cap

Quote:
Originally Posted by brmustang View Post
Do you think itís possible it is creating a vacuum as it cools down?
A properly functioning radiator cap will not allow the system pressure to go much lower then atmospheric pressure as long as the water height in the overflow reservoir to close to the same height as the top of the radiator.
__________________
Try not to take everything so literally. Just because someone suggests it's time to deal with the Elephant in the room doesn't mean you should break out the peanuts.

Thanks to:

HALTECH (Elite 2500 plus REM)
TRZ MOTORSPORTS
REAL STREET PERFORMANCE
FB PERFORMANCE
PTC
M/T Tires
Kris Starnes Racing

EMAIL - [email protected]
Topfun99 is online now   Reply With Quote
Sponsored Links
Advertisement
 
Old 10-15-2019, 12:35 PM   #40
1leg
Member
Pullin gears
 
1leg's Avatar
 
Join Date: Jul 2011
Location: Escondido
Posts: 700
Garage
Default Re: What psi radiator cap

Quote:
Originally Posted by blackmagicturbo View Post
The fastest 4.6 modular engine builder in the world told me that you want higher pressure to push water to the metal surfaces of the engine under power, so there is no steam. i run a 30+ pound cap.
This is why in some boosted applications a mechanical driven water pump works better then and electric water pump. Most electric water will only create about 5psi if you deadhead it. A mechanical pump can create 20psi or more. This is why I will almost alway recommend a mechanical water pump on land speed race cars.
1leg is offline   Reply With Quote
Reply

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



All times are GMT -4. The time now is 05:49 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 0%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Yellow Bullet LLC
 

Garage Plus vBulletin Plugins by Drive Thru Online, Inc.