Advice on a radiator cap for 1970 383

[petebryan]

Hi all, I'm trying to find a radiator cap for m,y 1970 cuda 383 (with its original rad). Couple of questions that am hoping for some help with:
- Most internet sources talk of 16psi being the norm though there is mention of 14psi. Does anyone know if there is a correct rating?
- There are a few places in the US I an order them from but does anyone know of anywhere in the UK that might have one?
- The previous cap I picked up was a little too short to seal at the bottom. Might be too obscure a question, but I wonder if there Is a range of 'neck' sizes for the various 1970s mopar radiators? Looks like I need a cap with a 20mm neck to fit my rad.

thanks in advance for any thoughts.
Pete

[Dave999]

to be honest i used to just through the boxes at halfords.

my aussie car came with a 7 lb cap originally

its currently got a MR Gasket one that i got off Mr Billadeau Snr when he had a bit of a stall set out at the NATS a few years ago

i'd imagine its a higher rated cap than 7 Lb/inch*2 probably between 10 and 15.

ah found one think they do a range.

https://www.ebay.com/itm/Mr-Gasket-2481 ... SwfN5a0pAo


don't go mad unless you have robust pipes, potentially braided....
standard rubber won't like a 20LB cap

the US message boards tend to go for bigger is better....in this case i'm not sure it is. i'd rather know i had some other problem causing my engine to overheat rather than mask it with a 25LB cap


I always have problems with caps as the neck of my radiator is so worn where the cap tangs fit. i just bend them (in the cap) until the cap is a struggle to fit. i'm reluctant to apply the mole grips to the spout....radiators cost more than caps

the spring loaded bit needs to seat properly and the cap needs to seal to the top of the spout.
if the latter doesn't you get blue rain on the screen.
the spring loaded section can be short or long if you get the wrong one it won't seal.

i'd suggest long....

like these https://www.ebay.co.uk/sch/i.html?_from ... h&_sacat=0


it appears that mopar used a pretty standard/universal fitment and at least one of the UK manufacturers followed suit based on my success at halfords

check land rover MGB etc on ebay you will find plenty of 10 LB caps no idea if they fit but i'd suggest there is a 80% chance they will

did jensens use a mopar radiator as well as engine?????

Dave

[petebryan]

Many thanks Dave, much appreciated.

[Dave999]

https://www.ebay.co.uk/itm/Mopar-340-38 ... Sws5pZHkqU

this one according to Mr Ehrenberg (Tech ed. Mopar action) is a 16lb cap made by an OEM supplier to chrysler !

Dave