Purple shaft question...

Purple shaft question... - 07/01/13 05:57 AM

I have a .590 for my small block and the lash is recommended to be set at .28/.30 cold. How much can I tighten or loosen this up and be safe? Could someone explain why these are set up to have that much lash in them? Thank you.

Posted By: MR_P_BODY

Re: Purple shaft question... - 07/01/13 06:13 AM

I havent run that cam but I do have a roller that calls
for 28/30 lash... right now I have it set at 18/18 with
alum heads... hot

Posted By: rt66jim

Re: Purple shaft question... - 07/01/13 02:48 PM

I have run it at .016 &.018 with iron heads. Jim

Posted By: Cab_Burge

Re: Purple shaft question... - 07/01/13 05:41 PM

I would try it stock at the track and then tighten it up .003 to .006 at a time to find out which way you want to run it

Posted By: Sb Valiant

Re: Purple shaft question... - 07/07/13 06:42 PM

I have the .590 cam too and I think the valve lash setting atleast on ours 28/32 was to loose. Will be experimenting with tighter valve lashes and see where it ends up!

Posted By: Dunnuck Racing

Re: Purple shaft question... - 07/07/13 06:46 PM

I had good results with both lobes lashed at .018" on both big and small blocks. Made a little more power on the dyno,and faster e.t. at the track.
Keith

Posted By: 77DragracerR/T

Re: Purple shaft question... - 07/21/13 04:07 AM

I run that cam in my 408 and I set it 28/32 and the car is very consistant with that setting and has been problem free.I've heard of racers running them tighter but I just don't want the failure problems.

Posted By: VernMotor

Re: Purple shaft question... - 07/21/13 02:59 PM

Quote:

I run that cam in my 408 and I set it 28/32 and the car is very consistant with that setting and has been problem free.I've heard of racers running them tighter but I just don't want the failure problems.

Why do you think you would have failure problems ?

Posted By: Dartthunder340

Re: Purple shaft question... - 05/05/17 08:52 PM

Hello everyone, hope all is well! I wanted to bump and revisit this. Was wondering if anyone else was running lash different than the .28/.30 Mopar recommendation? I still have my same combo of Aries domed pistons/ open chamber W2's and the .590 Purple Shaft. I did set it to .25/.25 cold and didn't notice any difference. I would like to go a lot tighter (.18/.20?) to see if there would be gains. Do you see any possible issues? Thanks again for your help!

Posted By: lil mope

Re: Purple shaft question... - 05/05/17 09:11 PM

I have the 557 solid on a 360 with eddy heads and runs best at .026 cold across and adds 5 more cranking comp.From 140 to 145. Never had a problem that loose even on turnpike.
Rick

Posted By: ProSport

Re: Purple shaft question... - 05/06/17 12:47 PM

I've seen alot of guys tighten the lash up on the 590 cam with good results but it never helped mine, it liked 28/32 in my 451 with Eddy heads and it was a 9 second bracket car. Maybe it just didn't like the extra lift since it was a mild combo with low compression.