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| | | | Joined: Oct 2006 Posts: 31 Apprentice | | Apprentice Joined: Oct 2006 Posts: 31 | Hello,I have a '49 3100 and I swapped the radiator out of a '47 as it was in better shape.I went to the parts store to get a 4 lb. cap and when they looked up the numbers it came back as a 0 pressure cap.I also noticed that Classic Parts offers a 0# and a 4# cap.Could someone please set me straight?By the way,its got a 235 babbit motor out of a '52.There doesn't appear to be a sealing lip in the fill neck to use a pressure cap. Confused, Chip | | | | | Joined: May 2005 Posts: 8,878 . | | . Joined: May 2005 Posts: 8,878 | Have a radiator shop swap necks for you.
I would want to use the 4lb cap
Grigg | | | | | Joined: May 2001 Posts: 709 Shop Shark | | Shop Shark Joined: May 2001 Posts: 709 | Second that but wouldn't go over 4lbs
Bruce
Old Toy: Ol' Betsy stock 59 Apache SB Stepside (Gone but not Forgotten)
New Toy: 1962 Impala SS Coupe
The Driver: 1990 Toyota truck
| | | | | Joined: Oct 2006 Posts: 4,983 Master Gabster | | Master Gabster Joined: Oct 2006 Posts: 4,983 | You could always run the 0# and carry a jug of water with you. 
~Jim
| | | | | Joined: Feb 2005 Posts: 469 Shop Shark | | Shop Shark Joined: Feb 2005 Posts: 469 | I' go for the 0# cap and not risk the radiator whats the risk of using a little water over loosing the radiator . Afer runing a 46 chevy over 532 miles and looosing less than a quart of water throught the Bosten mountians of Arkansass the presssure cap seems usless. The old truck my buddy and I ran was put to the max of It's maximune work level and never got over 195 on the temp gauge. | | | | | Joined: Mar 2006 Posts: 1,703 Shop Shark | | Shop Shark Joined: Mar 2006 Posts: 1,703 | | | | | | Joined: May 2005 Posts: 8,878 . | | . Joined: May 2005 Posts: 8,878 | I drove my 52 with a pressure cap and a 235 for 8,000 miles in june driving around the country, needed no water.... | | | | | Joined: Mar 2005 Posts: 637 Shop Shark | | Shop Shark Joined: Mar 2005 Posts: 637 | 4# cap creates minimal pressure and will not damage a radiator but gives you about 12 to 14 degrees margin in case of overheating before losing water. The 4# cap is a good idea in m opinion. | | | | | Joined: Jul 2006 Posts: 92 Wrench Fetcher | | Wrench Fetcher Joined: Jul 2006 Posts: 92 | I just put a 283 in mine and a new radiator, should i run a 4-7 lb. cap or what?...Virg | | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | I wouldn't use more than a 7# Virg if it's a stock style rad - works well for me w/ a 283
Bill | | | | | Joined: Dec 2001 Posts: 14,522 Moderator: Welcome Centre, Southern Bolters, Legion Hall | | Moderator: Welcome Centre, Southern Bolters, Legion Hall Joined: Dec 2001 Posts: 14,522 | Was there a 235 babbitt engine??? Hey, I run the 4lb cap on my 350 to keep from spliting the 1937 original top and bottom tank wide open! I have a new core but had the shop do as mentioned above. Changed the neck to run pressure cap. Sometimes it gets a little warm if in a parade on a real hot day but otherwise no problems. | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | A low-pressure 235 was used in big trucks from 1941-1953.
I believe the Shop Manuals recommend 0 lbs pressure in small truck engines until 1953; 4 lbs in 1954/55; 7 lbs in passenger cars. I do not know about 55+ trucks/cars or medium/heavy trucks.
4 lbs should be OK, if your radiator takes a pressure cap. I have run 4 lbs in a 54 235 for years - no boil over or loss of fluid. | | | | | Joined: Jun 2006 Posts: 85 Wrench Fetcher | | Wrench Fetcher Joined: Jun 2006 Posts: 85 | the only cap i could for my 51, 3100 with a babbit 235 is a 7# will this be ok? ( i replacet the frozen 216 with a 48, 235) | | | | | Joined: Jul 2021 Posts: 44 'Bolter | | 'Bolter Joined: Jul 2021 Posts: 44 | I new to this numbering cap thing. My manual for 1952 1T does not show what should be used. Goofing around I looked in a classic parts catalog and it shows for the 52 to use the #0 (as previously mentioned). I’m in New England, thermostat in truck now is a 180*. Truck is Not a Dailey driver as it was a logging truck and is geared low. My top speed is like 40mph.
Antifreeze has just been changed w new green also. Also adding, there are no leaks or over heating or anything, I only want to replace cap as the rubber is all cracked and worn etc.
So would it be safe to say...use the #0? | | |
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