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Hemi hydraulic cam adjustment #289423 04/15/09 08:05 PM 04/15/09 08:05 PM
Joined: Dec 2006 Posts: 114 pawling n.y. C cudachas OP member
cudachas OP member C Joined: Dec 2006 Posts: 114 pawling n.y.	Has anyone adjusted the valves on the newest 426 hemi crate motor from chrysler. Instructions say to adjust them to zero lash and then turn them in another 1 and 1/2 turns. Seems like alot to me.I would think that closer to zero would be better but this is my first hemi so maybe thats what they like. This thing only makes about 8 inches of vacuum at idle with the timing at 32degrees.The cam is stock with 278 duration so I think it should make alot more vacuum as my wedge with 284 cam made about 11 inches of vacuum (adjustable rockers 1/4 turn preload). Any ideas? Thanks , Charlie.

Re: Hemi hydraulic cam adjustment [Re: cudachas] #289424 04/15/09 09:51 PM 04/15/09 09:51 PM
Joined: Nov 2003 Posts: 2,715 closer to Canadian beer! torkrules I'm neurotic
torkrules I'm neurotic Joined: Nov 2003 Posts: 2,715 closer to Canadian beer!	Quote: Has anyone adjusted the valves on the newest 426 hemi crate motor from chrysler. Instructions say to adjust them to zero lash and then turn them in another 1 and 1/2 turns. Seems like alot to me.I would think that closer to zero would be better but this is my first hemi so maybe thats what they like. This thing only makes about 8 inches of vacuum at idle with the timing at 32degrees.The cam is stock with 278 duration so I think it should make alot more vacuum as my wedge with 284 cam made about 11 inches of vacuum (adjustable rockers 1/4 turn preload). Any ideas? Thanks , Charlie. What's the lobe separation? This will dictate how much overlap the cam has. The smaller the number the more overlap and less vacuum you will have. I have a Comp Cam (FHO spec) hydraulic in my 472. I'm pulling 18" of vacuum. This cam has 274 duration and 113 degree lobe separation. I adjusted mine 1/2 turn past zero lash. I think 3/4 turn would be as far as I would go. Hemi valve gear is a little on the noisy side even when properly adjusted.

Re: Hemi hydraulic cam adjustment [Re: torkrules] #289425 04/16/09 04:31 AM 04/16/09 04:31 AM
Joined: Dec 2006 Posts: 114 pawling n.y. C cudachas OP member
cudachas OP member C Joined: Dec 2006 Posts: 114 pawling n.y.	Thanks, I don't know the complete spec's on the cam, only what mopar advertises and that's 278 durration and 480 /495 lift. They are down a turn and a half now so I think I will pull one cover and back them off 1 turn and see what happens. Charlie.

Re: Hemi hydraulic cam adjustment [Re: torkrules] #289426 04/16/09 07:52 AM 04/16/09 07:52 AM
Joined: Aug 2005 Posts: 4,799 ILL M MLR426 master
MLR426 master M Joined: Aug 2005 Posts: 4,799 ILL	Quote: Quote: Has anyone adjusted the valves on the newest 426 hemi crate motor from chrysler. Instructions say to adjust them to zero lash and then turn them in another 1 and 1/2 turns. Seems like alot to me.I would think that closer to zero would be better but this is my first hemi so maybe thats what they like. This thing only makes about 8 inches of vacuum at idle with the timing at 32degrees.The cam is stock with 278 duration so I think it should make alot more vacuum as my wedge with 284 cam made about 11 inches of vacuum (adjustable rockers 1/4 turn preload). Any ideas? Thanks , Charlie. What's the lobe separation? This will dictate how much overlap the cam has. The smaller the number the more overlap and less vacuum you will have. I have a Comp Cam (FHO spec) hydraulic in my 472. I'm pulling 18" of vacuum. This cam has 274 duration and 113 degree lobe separation. I adjusted mine 1/2 turn past zero lash. I think 3/4 turn would be as far as I would go. Hemi valve gear is a little on the noisy side even when properly adjusted. I agree with 1/2 to 3/4 turn on preload. logan426

Re: Hemi hydraulic cam adjustment [Re: MLR426] #289427 04/17/09 06:47 PM 04/17/09 06:47 PM
Joined: Dec 2006 Posts: 114 pawling n.y. C cudachas OP member
cudachas OP member C Joined: Dec 2006 Posts: 114 pawling n.y.	Thanks, will adjust the valves tomorrow , I will post results. Charlie.

Re: Hemi hydraulic cam adjustment [Re: cudachas] #289428 04/20/09 08:57 PM 04/20/09 08:57 PM
Joined: Dec 2006 Posts: 114 pawling n.y. C cudachas OP member
cudachas OP member C Joined: Dec 2006 Posts: 114 pawling n.y.	I backed the valves off 1 full turn and no valve noise. It didnt pick up any vacuum either, must be in the cam. Good thing I dont have power brakes. Charlie.

Re: Hemi hydraulic cam adjustment [Re: cudachas] #289429 04/20/09 09:06 PM 04/20/09 09:06 PM
Joined: Jan 2003 Posts: 15,357 Omaha Ne T TJP I Live Here
TJP I Live Here T Joined: Jan 2003 Posts: 15,357 Omaha Ne	Most camshaft manufacturers reccomend .020 to .040 lifter preload. This has bee the standard for years. So if one looks at the adjuster and it is a 3/8 - 24 thread, 1 turn equals .0416" So assuming you have a 3/8 x 24 thread 1 turn beyond ZERO lash will equal .0416 of preload. Hope this helps www.tandmautomotive-omaha.com

Re: Hemi hydraulic cam adjustment [Re: TJP] #289430 04/22/09 04:00 PM 04/22/09 04:00 PM
Joined: Dec 2006 Posts: 114 pawling n.y. C cudachas OP member
cudachas OP member C Joined: Dec 2006 Posts: 114 pawling n.y.	Thanks, thats what they are 3/8-24.They are down a half turn so I should be in the ball park.Charlie.

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