Has anyone used sub-harmonic stress relieve on engine parts ?

I have a 406 project in work and I have access to a sub harmonic stress operation. I know I can reduce the chances of stress and fatigue failures on my re ground crank and rods.

My concern is that I may see movement of the crank journal positions. Can't guess how much though without experiment. The crank is already ground 10-10. If it moves I will need another grind. If anyone has used this proces was it before or after grind ?

[ 12-10-2003, 08:45 AM: Message edited by: jackr ]

Jack, how much HP do you want? You want to spin that 400 to 9K or what?

I think that he wants just enough power to run about 12.09 @ 113 (to stay ahead of you Lonnie). :D

9K would be a kick wouldn't it !! No, not for this engine but..
I can do that process in our shop. Someone somewhere told me that the pro-engine guys are using sub-harmonics to lengthen the fatigue life of their cranks and rods. Don't remember who or how though.

We use this process a lot on high precision machined gearboxes that have stress problems as a result of machining. It is an amazing process in that it stabilizes the metal without using the thermal stress relieve processes that normally distort machined parts.

And furthermore, I should use some of this aerospace engineering in my camaro ?

[ 12-10-2003, 01:17 PM: Message edited by: jackr ]

Here is some very good info on the topic
http://www.meta-lax.com/no_flash/PDF/general.PDF
Great discussion here!
http://www.eng-tips.com/viewthread.cfm?spid=330&newpid=330&sqid=61212
http://www.personal.psu.edu/users/b/j/bjh221/newwave.html
Bob

Thanks for the links. Our equipment is meta-lax from the first link.

We have used this for about 5 years with great success on aluminum, titanium and other high strength steel machined parts. Before using the meta-lax, it was common to fight stress movement during or after machining processes were completed. We had a gearbox that has .0005 position tolerance over 2.5 feet. About 30% of the boxes would move after machining causing centerline alignment problems when the cover and gears were assembled. Since implementing this stress relieve method, the problem is gone.

And, the eng-tips website I visit often for work matters too.