Farm Equipment - B model radiator - pressurized vs non pressurized

Print Page | Close Window

B model radiator - pressurized vs non pressurized

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=48427
Printed Date: 23 Aug 2025 at 6:17pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: B model radiator - pressurized vs non pressurized

Posted By: outlook6
Subject: B model radiator - pressurized vs non pressurized
Date Posted: 03 Apr 2012 at 4:42pm

Does anyone have any information regarding when AC started putting pressurized radiators on the model B? I'd be interested in knowing at approximately what serial number the change was made. I need to replace the radiator on my 1940 B and believe it was originally non pressurized. The only sources I've been able to find for new radiators are all pressurized. Just want to find out if my serial number would be correct with the pressurized version.

Also if anyone knows of a source for the non pressurized version I'd appreciate getting that info as well.

As always any help is greatly appreciated.

Jim

Replies:

Posted By: Chalmersbob
Date Posted: 03 Apr 2012 at 9:57pm

look at the neck of the radiator. if it takes the same cap as the gas tank, it's not pressurized. You will also find the neck to be wide open without a flange for a sealing gasket as used on pressure caps.

I guess you can use a pressurized radiator but not use a pressure cap. Just remove the gasket. Bob

Posted By: outlook6
Date Posted: 04 Apr 2012 at 8:17am

Thanks Bob. I understand the physical difference between the two radiators and their caps. The radiator I have is unusable.

My question is whether either would be correct for a 1940 B. I bellive it should be the non pressurized type, but the only new radiators I can find for sale are the pressurized versons.

Regards, Jim

Posted By: Dick L
Date Posted: 04 Apr 2012 at 11:17am

These B and C types of engiines do not need to be pressurized to keep cool. The engine design didn't change from the begining to the end. If you use a pressure cap it would be best to not go over 7 pounds.

Posted By: outlook6
Date Posted: 04 Apr 2012 at 1:32pm

Dick,

Now I understand. So it's the cap that makes the difference, pressurized or not, not the radiator. I assume any new radiator I buy will accept either cap.

Thanks again and regards,

Jim

Posted By: Tony.Or
Date Posted: 04 Apr 2012 at 4:58pm

Don`t forget when you buy a new B , C , CA radiator it will have the new style Neck, made for pressure cap," ie" hooks from out side NOT inside like old originals.

So old style lever caps won`t fit new radiators. Tony

-------------
http://www.tonystractors.com" rel="nofollow - http://www.tonystractors.com

Posted By: Gerald J.
Date Posted: 04 Apr 2012 at 6:09pm

Its conceivable the tanks and tubes for a pressurized system are made of heavier metal to stand the pressure.

Its sure that with a 180 degree thermostat you need a pressurized system to keep it from boiling.

Its sure that with a 180 degree thermostat you can't use an alcohol based antifreeze, you need a permanent (glycol based) antifreeze that also raises the coolant boiling point. Much of the antifreeze in the unpressurized tractor era was not called permanent.

Thermodynamics indicate that an engine with a 180 degree thermostat is a bit more efficient because with a higher temperature cooling system less combustion heat is lost to the coolant. There are limits set by survival of valves, head and especially cylinder wall lubrication which still prevent going to higher coolant temperatures.

It may be possible to find a none pressurized or very low pressure cap like 1 or 2 pounds to fit the replacement radiator. I'm sure a drop of solder in the right place or a bit of picture hanging wire or a 1/32" drilled hole can convert a 15 psi cap to nonpressurized. Just it won't look like a 1938 radiator cap.

Gerald J.

Posted By: pumpkinman
Date Posted: 04 Apr 2012 at 7:59pm

None pressure rads. were used prior to tractor # B61222

Posted By: pumpkinman
Date Posted: 05 Apr 2012 at 11:19am

Have your old rad. recored if the tanks & frame are still good - or have your filler neck

put on the new rad.