Correct Rad Cap for '48

[vicbrincat]

Hi folks,

Finally got my car on the road.
Still working out all the "bugs", of course.
One bug is coolant leaking out of the rad overflow after a good run. First of all I have only had the car out about three times...but it has dumped fluid each time. (Granted I probably over-filled the rad originally).
I suspect that it will eventually reach equilibrium and stop overflowing....
But just to be on the safe side....what is the correct PSI rating of the rad cap?
I purchased mine from Coopers  who are (IMHO) reliable, and it is supposed to be correct for '48...but it has no PSI value on it..just double checking just because I may have got the wrong one by accident.

Vic

[Bill Ingler #7799]

Hi Vic: The correct cap for your car is an A/C cap RC-7 which as a 9# cap. This cap as you see by the attached chart is correct for 41-48. The cap will have A/C stamped on one ear. In very small letters under A/C will be 558-9#, then under that, RC-7.The neck of the cap should always be 1/4 inch longer than the neck of the radiator to give a good seal when you press down and turn to lock the cap. Jeff Maltby sent me pictures of your car. You have done a beautiful job on the restoration. With the correct cap the the fluid level on the top tank will vary a little on each car but I have found with my old 41 and my 47 the level will settle at about 2 inches below the neck of the radiator.  Bill

[vicbrincat]

Thanks Bill,

I have to tell you that Jeff has been a great source of info for me...despite his preferences to Over-head valve engines...;-)

Based on the info that you have provided....mine isn't even close.
I did manage to find "7 lbs" stamped on the cap.

So the next logical question..where can I get the "correct" cap for my '48?


Thanks in advance.

Vic

[TMoore - NTCLC]

Vic -

Give Bob Cooper a call and let him know that you appear to have the wrong cap.  It happens sometimes, especially as he has been in the process of moving.  I ordered the cap for my 1942 from him, and it is the correct longer neck cap.  There have been a couple of items that I ordered that were the wrong ones, but he will take care of it.

Let him know what you have and what you are expecting, and I bet he can get it to you -

Tod

[Bill Ingler #7799]

There have been several caps on ebay the last few months-$25-35. That is probably your best place. I would also post your wants  on the Buy/Sell on this forum or call Ed Cholakian at Cads of the 40s.

[Jeff Maltby 4194]

Vic. Here's the difference between a 559-13lb 49-55 cap versus the correct cap off a 48 FB I parted out years ago, with approx a 1/4" height difference.

Measure down the rad cap throat to top neck then check your new cap to compare. Sounds like Coppers sent you the wrong cap either way.  

PS ! I have no problem with the flatheads versus an ohv engine. I bought a 48 fastback that hadn't run in 25 years and with a little cleaning/tinking, it fired up with zero smoke and purred much smoother then an OHV engine. I like the larger 49 grille smile better then the 48 but miss the 3 chevrons under the tail lights  :<)