Tommy Tucker

I know some guys have had problems UN-DOING the jam nuts on their Crane rockers. They end up winding out the posts. I've had this problem and have ruined some of the jam nuts in the process of trying to un-do them. I'm sure there are others out there, but it's not something you brag about .Thankfully I've managed to get hold of some spares in the UK (not easy).
Does anyone have any tried and tested tips that will make the jam nuts hold tight enough but allow them to be undone?
Any suggestions welcome. Thanks.

vettenuts

iTrader: (4)

I put mine in a 3/8-24 nut and then exposed a small portion of the jam nut and using a flat surface and sand paper flatted the surface that digs into the stud. Haven't tried backing them out since I did this, but I ran into your problem. At the time I was changing heads so I didn't care, but when I maintain my valve springs I don't want to have to deal with this again either. I may pick up a new set of jam nuts from McMaster-Carr that has a flat bottom surface.

I ended up buying a Snap-on stud tool and using that to hold the stud (of course all the studs had backed out of the head at this point), then with the stud tool held fixed, and using a 1/2 inch socket, the nut came right off without damaging the threads. Here is a link to my thread, it was not fun at all and I considered going back to stock rockers but I just couldn't bring myself to do that because of the Crane quality and their excellent wipe pattern.

Link

Tommy Tucker

Thanks for the advice. Sorry I couldn't respond before but I've been away for the weekend.

I was thinking of flattening the cup end of the jam nut as well so I'll try that.
I'm presuming yours haven't come loose. Did you do the final 1/4 turn together thing to finally tighten?
I'll look up the stud tool too.
Cheers,
Tom.

vettenuts

iTrader: (4)

I did 1/8th turn, you really can't get much more than that.