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Valvetrain deflection and geometry #3220924 03/16/24 10:22 PM 03/16/24 10:22 PM
Joined: Oct 2018 Posts: 22 Indiana M Mbrown OP member
Mbrown OP member M Joined: Oct 2018 Posts: 22 Indiana	I am setting up the valve train on a 540 and wanted some opinions on what to do. I have always used B3 shaft relocation kits, but now I am having second thoughts. I want to make it clear that i am not bashing Mike or his products. I am just having trouble with this application. I have measured valve lift with checking springs and the actual springs. I did all checks with 0 lash to help eliminate human error. Lobe is .465" . The rocker arms are advertised as 1.7 ratio. My springs are 255#'s on the seat and 660#'s at .770 lift. With shaft relocation kit, lift at valve was .771 with checking spring. The lift at the valve with the real spring was .712". That is A LOT of deflection. Scrub pattern was .045-.050" wide and centered. I am not happy having that much deflection. So I decided to check without the shaft relocation kit. Without the shaft relocation shims, the lift at the valve with checking springs was .790". The lift at the valve with the real springs is .776". The scrub pattern is huge though. .090-.100", but centered. My question is, do I run with or without the relocation shims? I have considered machining new hold downs that would help stabilize everything when using the relocation kit. Any suggestions?

Re: Valvetrain deflection and geometry [Re: Mbrown] #3220951 03/17/24 06:12 AM 03/17/24 06:12 AM
Joined: Jan 2003 Posts: 10,000 Frostbitefalls MN (Rocky&Bullw... gregsdart I Live Here
gregsdart I Live Here Joined: Jan 2003 Posts: 10,000 Frostbitefalls MN (Rocky&Bullw...	I am not well versed in stock type valvetrain, but my first thought was can you put a dial indicater on the shaft to see where some of the deflection is coming from? With, and without shim kit. I have often wondered if an overhead bridge of some sort might reduce shaft flex, but having switched to Jesel stuff never tried anyrhing like it . Last edited by gregsdart; 03/17/24 06:16 AM. 8..603 156 mph best, 2905 lbs 549, indy 572-13, alky

Re: Valvetrain deflection and geometry [Re: Mbrown] #3220953 03/17/24 06:49 AM 03/17/24 06:49 AM
Joined: Nov 2011 Posts: 287 PA Harry's Taxi 2 enthusiast
Harry's Taxi 2 enthusiast Joined: Nov 2011 Posts: 287 PA	Originally Posted by Mbrown I am setting up the valve train on a 540 and wanted some opinions on what to do. I have always used B3 shaft relocation kits, but now I am having second thoughts. I want to make it clear that i am not bashing Mike or his products. I am just having trouble with this application. I have measured valve lift with checking springs and the actual springs. I did all checks with 0 lash to help eliminate human error. Lobe is .465" . The rocker arms are advertised as 1.7 ratio. My springs are 255#'s on the seat and 660#'s at .770 lift. With shaft relocation kit, lift at valve was .771 with checking spring. The lift at the valve with the real spring was .712". That is A LOT of deflection. Scrub pattern was .045-.050" wide and centered. I am not happy having that much deflection. So I decided to check without the shaft relocation kit. Without the shaft relocation shims, the lift at the valve with checking springs was .790". The lift at the valve with the real springs is .776". The scrub pattern is huge though. .090-.100", but centered. My question is, do I run with or without the relocation shims? I have considered machining new hold downs that would help stabilize everything when using the relocation kit. Any suggestions? I've just been through the same observation when changing to a different flat tappet cam using the B3 setup. I noticed a fair amount of fretting/walking marks on the shims so i checked side to side flex at the hold down stud and it was around .0015-.002. and this is with 150# seat pressure and .620 lift. I switched from using the B3 kit with Hughes rockers to a T&D rocker assembly. The pattern isn't quite as centered (very close to center though) now, but is as narrow and it is much closer to full lift with flex at hold down stud gone now. I have another engine with roller and Jesel 1.7 individual shafts and @.799 theoretical lift, it only loses about .015 to actual lift at retainer w/ 350# seat springs....scrub was minimal, but i don't recall actual width. I think the B3 kit is a good idea, but it has spring pressure and lift limits. Last edited by Harry's Taxi 2; 03/17/24 06:57 AM. '86 Maple Grove KOS Mopar low qualifier......true street legal with no power adders. NOS-used when losing since 1940.

Re: Valvetrain deflection and geometry [Re: Mbrown] #3220986 03/17/24 10:50 AM 03/17/24 10:50 AM
Joined: Jan 2003 Posts: 31,036 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 31,036 Oregon	At 0.790 gross lift you should be using high quality rocker arms, especially if you're going to turn the engine past 6000 rpm. T&D is probably the best choice at that level although a switch to Jesel could also make sense if the engine is designed to make a lot of passes. I would not run anything that deflects as much as what you are measuring. That deflection will occur every rotation of the engine so those shafts will be vibrating like guitar springs at 6000 rpm.

Re: Valvetrain deflection and geometry [Re: AndyF] #3221000 03/17/24 12:06 PM 03/17/24 12:06 PM
Joined: Mar 2006 Posts: 9,836 MI, usa dvw master
dvw master Joined: Mar 2006 Posts: 9,836 MI, usa	My paired T&D 1.7 show less than .010" loss at 805lbs over the nose. Doug

Re: Valvetrain deflection and geometry [Re: AndyF] #3221055 03/17/24 02:36 PM 03/17/24 02:36 PM
Joined: Oct 2018 Posts: 22 Indiana M Mbrown OP member
Mbrown OP member M Joined: Oct 2018 Posts: 22 Indiana	What's an acceptable amount of deflection? I will retest with a larger diameter pushrod when I get in the shop Monday morning. Right now without the offset shims I am at .014" deflection. Last edited by Mbrown; 03/17/24 02:54 PM.

Re: Valvetrain deflection and geometry [Re: Mbrown] #3221172 03/18/24 06:53 AM 03/18/24 06:53 AM
Joined: Nov 2003 Posts: 1,839 NW Indiana F fbs63 top fuel
fbs63 top fuel F Joined: Nov 2003 Posts: 1,839 NW Indiana	That kind of lift and spring pressure needs individual shaft paired rockers. I cannot imagine what the rockers and shafts go through when you try to install them much less how much deflection it has running with the geometry correction hardware raised shaft position.

Re: Valvetrain deflection and geometry [Re: fbs63] #3221184 03/18/24 08:30 AM 03/18/24 08:30 AM
Joined: May 2005 Posts: 1,986 Apollo, PA. B1MAXX top fuel
B1MAXX top fuel Joined: May 2005 Posts: 1,986 Apollo, PA.	What push rod?

Re: Valvetrain deflection and geometry [Re: B1MAXX] #3221185 03/18/24 08:33 AM 03/18/24 08:33 AM
Joined: May 2005 Posts: 1,986 Apollo, PA. B1MAXX top fuel
B1MAXX top fuel Joined: May 2005 Posts: 1,986 Apollo, PA.	The only thing geometry wise that effects it will be how much adjuster you have "hanging"out.

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