[DeTomaso] Pressure cap pressure

[JDeRyke at aol.com]

In a message dated 8/17/09 3:39:33 PM, asajay at asajay.com writes:


> What is the proper pressure rating for the cap we should use on the swirl 
> tank?
> 16 lb?
> 18 lb?
> 120 lb?
> 
I have an article on this very subject in the Sept POCA News (now in 
print). Stock was 0.9-bar (equiv. to a 13 lb cap). I've successfully run up to a 
16-lb cap on a non-stock copper radiator but I would not go higher on copper, 
give the thin-ness and general fragility of the tubes. With stronger 
aluminum radiators, you can go as high as 20 lb cap (stock early '90s Mercedes 
w/aluminum rad), giving you a little more margin before boiling. But to run 
that high a system pressure, you better have good clamps everywhere and high 
quality hoses -including the heater hoses AND the two short ones under the 
dash.... or you'll soon find out where your weak spot is! Good luck- J Deryke