Radiator cap?

[Gearhead10]

Gonna get the engine broke in soon in the A and had a question about radiator cap. Our radiator is a orignal piece that has been recored and modified to work for the SBC. We have a 16lb cap on it now but I was thinkin that maybe a 8lb would be better, less pressure. Not sure if the tanks could hold up to alot of psi or not. We got over $400 invested in the dang thing so I'd hate to blow it out. We had it redone several yrs ago before aluminum radiators were avalible. What do you all think? Thanks

 

[Gastrick]

Original tanks? Then I would use the lower pressure cap. I know some people get away with the high pressure caps on original tank radiators......but others blow them out.

 

[Gearhead10]

Yea, original tanks. The lower one was turned around, filled and new outlet put on so the lower hose would be at the rh side for the water pump. Upper tank had the cap filled and a remote fill neck for the cap moved to the side a bit and I believe the inlet pipe was redone also. It has had all new cores installed and I think it was all re-soldered. I have an expansion tube bolted to the side of the grill shell. I just think a lower psi cap would be safe insurance. Its not like I need a larger psi cap, Im not plannin on racin her. Not yet anyway [ddd.

Not a real detailed pic but ya get an idea maybe.

 

[CR55]

I have a mostly original tank on mine and made the mistake of running with a low pressure cap. It spewed antifreeze every time the temp went to the normal operating level. Put a 14lb on it and no more problems. I would try a low one on yours first but carry a higher pressure with me and test them out. Good luck and carry extra fluids!.... CR

 

[HotRodCadillac]

Let's not forget why we use a pressure cap to begin with. Pressurizing a liquid raises it's boiling point. I'd say go with a 12-14 lb cap and you should be fine.

 

[saamkl]

I have a Radiator in my 47' that came out of a 33 vickey. It's been modified back in the day with a combination of ford and chevy tanks. It was done nice, but I had it cleaned and checked and repaired. The place pressure checked it and all was good. I am running a low pressure cap, i think it is a 8lb. I too have the same problem with it pushing antifreeze out at operating temp. I am going to put a 10lb or 12lb on it and a catch can. I think a 16lb cap is way too high for an original tank.

 

[CR55]

16 was too high for me. Ended with a 12....CR

 

[Willowbilly3]

On my first rod, when I was 15, I ran a J2 Olds with a 50 Ford pickup radiator. It had a large weird cap and I couldn't find a higher pressure one, it steamed all the time. I think it was 3-4 psi though.

 

[Gearhead10]

Thanks for the input guys. I think a 10 or 12lb will be the ones I'll try. Thats what I like about askin a ? here, honest and reliable answers. Thanks again