As I believe that many of you already know from my previous posts, my son and I restore the old Briggs and Tecumseh horizontal shaft L-heads. Most of these engines are 40-55 years old and many parts are no longer available (NLA). I learned my lesson long ago that SOME NOS parts deteriorate with age to the point they are no longer usable (e.g, gaskets and rubber parts that dry out) as they are sold individually from an open box and no longer in sealed packaging. OK, enough background, now here's my question:
How about NOS metal parts (rods, cam gears, valves, crankshafts, etc.. Do these 50-50 year old parts go "bad"?
Does the structural integrity of the metal somehow deteriorate or become otherwise compromised with age? Many of the NOS metal parts I purchase have "surface rust" as described by the seller. How MUCH rust (with iron) or oxidation (with aluminum) is a deal breaker? Thanks for your insight.
Michael
