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#47245 07/04/2005 5:04 PM | Joined: Mar 2005 Posts: 170 Member | | Member Joined: Mar 2005 Posts: 170 | As I continue to get ready to swap out the tired 224 (Canadian cousin to the 216) for a freshly rebuilt 1955 235 in my 1940 GMC, more questions come to mind.
My origianal radiator is unpressurized - no pressure cap. If I recall correctly, by 1955 Chevy was using a 4 lb pressure cap with the 235 radiator. So will I need to run a 4 lb cap on my radiator? Or should it be Ok as is? Is this radiator strong enough to handle 4 lbs of pressure? Did they make the radiators out of heavier metal when they went to pressurization?
Thanks,
Steve
PS
While I have the radiator out for the engine swap I will take it to radiator shop for cleaning and testing. | | |
#47246 07/04/2005 7:34 PM | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | I would run a 4 or 7 lb. cap after you have the radiator cleaned & pressure tested. Some of those had the vent on top. If so have the radiator shop seal it up & make shure it has the apropiate neck for a modern pressure cap.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | |
#47247 07/04/2005 8:01 PM | Joined: Aug 2004 Posts: 399 Shop Shark | | Shop Shark Joined: Aug 2004 Posts: 399 | I run a 4 lb. on the 41 and I´m verry happy with it. I would go for it.
Frank | | |
#47248 07/05/2005 12:03 AM | Joined: Mar 2005 Posts: 170 Member | | Member Joined: Mar 2005 Posts: 170 | Frank, did you have to change the filler neck to fit the 4lb cap or did you find one that fits?
Thanks,
Steve | | |
#47249 07/05/2005 4:51 PM | Joined: Mar 2000 Posts: 784 'Bolter | | 'Bolter Joined: Mar 2000 Posts: 784 | Steve:
You need to have the overflow sealed up and install a new filler neck with the overflow right on the neck. Which is just like most of the modern filler necks. Then you can run up to a 7lb cap. No more than 7lbs though, the radiator seams won't hold more than that.
I"m running a 7lb with no problems. Just be sure your radiator is in good shape.
George | | |
#47250 07/06/2005 5:12 PM | Joined: Mar 2005 Posts: 170 Member | | Member Joined: Mar 2005 Posts: 170 | Thanks guys, I appreciate your advice.
Steve | | |
#47251 07/07/2005 9:25 AM | Joined: Aug 2004 Posts: 399 Shop Shark | | Shop Shark Joined: Aug 2004 Posts: 399 | Steve, the overflow tube inside the neck was grinded down til it was flush with the inner wall of the neck to make sure the rubber disc of the cap can move up and down. When 4 lbs are reached in the system the pressure presses the spring loaded rubber disc up and relases some water throu the tube. This happened only once on a verry steep mountain road after I turned the engine off. Usualy I never loose eany water. I got the cap from Chevs of the 40s Frank | | |
#47252 07/07/2005 2:45 PM | Joined: Mar 2005 Posts: 170 Member | | Member Joined: Mar 2005 Posts: 170 | Frank,
If all I have to do is grind down the overflow tube flush, that would be great. I'll take a look at it tonight.
Steve | | |
#47253 07/10/2005 4:51 AM | Joined: May 2005 Posts: 4 Junior Member | | Junior Member Joined: May 2005 Posts: 4 | I have a '40 Chev Coupe with original radiator and a 350 V-8 engine, 350 trans., and A/C.
I have been running a 15-17 # cap on the rad. as a closed system with overflow tank for almost 30 years without a problem. Never blew a hole in the rad.
Use the vent tube to run hose to overflow tank as modern cars do.
Just my Thoughts,
Walt | | |
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