Valve springs-good & bad

Studebaker JT engines used heavy duty valve springs. They are #188645 in the parts book. They were actually used in earlier engines which explains the older part number. Fortunately I had some but unfortunately only 8 instead of 16. This being a budget project I am going to try and make do. Above is a method of finding weak valve springs as used by our local Studebaker guru Gary Payne. You don’t need to run them in too much to find the which is squeezing more that the other. The new one is on the right and the old one on the left.

I tested all the old springs and picked eight of the best. They are all about the same height but noticeably lower than the new springs. When I squeezed an old with a new the difference was less than a 1/16″ which is a lot less than that between the uncompressed spring height. Since this is not going to be a race engine and not likely to often go over 3500 rpm I will try to use the used springs. That said I may go for all new springs if I can buy 8 new ones.

Next I’ll get into the rocker arms.

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