I was just wondering what pepole have seen for valve spring life span with cams in the 235 239 and 0.623 0.626 lift range. Also what tends to hapen when a spring brakes with pac duel springs.

 

if a spring breaks you will normally trash the head and that piston/cylinder, possibly the entire engine

 

Dual springs offer more protection. Some people check them at about 20K but someone here ran a set for 50K without issue.

 

I have 34k on a set of pac 1206x springs at the moment. Starting to think about swaping them.

 

In road racing, with a GT level engine, the springs get swapped about twice a season at the Amateur level..
They don't typically hold their pressure uniformly much longer than that. that's about 8 track weekends.

On a sprint car the springs get checked about every 8 to 10 race weekends. (406 small block running north of 9500.. )

 

I know more rpm and more lift equal shorter life.Has any one had a spring fail on them just due to use?

 

Some Comp 918 single springs have failed.

 

Fixed it for ya.....