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donny1973
Samba Member
Joined: November 21, 2008
Posts: 317
Location: Palm Beach, FL
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 Posted: Tue Apr 07, 2009 4:29 pm Post subject: No Valve Lash??? |
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I'm in the final stages of assembly of a complete rebuild on my '68 SP 1600. The motor is completely stock with the exception of a mild CB street cam and all parts are brand new with the exception of the crank and cases.
I just tried to intall the rocker shafts with a new set of Scat swivel foot adjusters. Even with the adujsters backed all the way out (as far as they can go in the rocker arms), I have no valve lash and in fact, the valves won't even close. The set came with eight flat rectangular spacers. I installed two on each rocker shaft mount to compensate for the wider head on the adjusters and still, even on the bottom of the cam lobes, the valves do not completely close. The set came with no instructions. It concerns me that even using all the spacers supplied, there's still no gap between the adjusters and the valve stem. Has anyone else had this experience? Any suggestions?
Thanks,
Donny
Last edited by donny1973 on Tue Apr 07, 2009 4:32 pm; edited 1 time in total |
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Glenn 
Mr. 010
Joined: December 25, 2001
Posts: 76939
Location: Sneaking up behind you
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| Posted: Tue Apr 07, 2009 4:31 pm Post subject: |
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You need to check your rocker geometry and most likely need shorter pushrods.
_________________
Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
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donny1973
Samba Member
Joined: November 21, 2008
Posts: 317
Location: Palm Beach, FL
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| Posted: Tue Apr 07, 2009 4:40 pm Post subject: |
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| Glenn wrote: |
| You need to check your rocker geometry and most likely need shorter pushrods. |
Easy for you to say. So there's no standard formula that says if you use these adjusters with all other parts being stock, the push rods need to be xx length? I can't be the first person to try this. |
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Eaallred
Samba Member
Joined: May 18, 2003
Posts: 5756
Location: West Valley City, Utah
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| Posted: Tue Apr 07, 2009 4:58 pm Post subject: |
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| donny1973 wrote: |
| Glenn wrote: |
| You need to check your rocker geometry and most likely need shorter pushrods. |
Easy for you to say. So there's no standard formula that says if you use these adjusters with all other parts being stock, the push rods need to be xx length? I can't be the first person to try this. |
There is no 'standard'. There are too many variables. engine case can be decked different amounts, heads can be flycut different amounts, these affect the width of the motor. Then the style rockers you are using, etc.
Basic for rocker geometry, is you want the adjuster to line up perfectly (with either valve or pushrod depending on what style rocker you have) at half lift. That way the system pivots equal amounts both ways. Full open and full closed are matched angles (just opposite).
An adjustable pushrod is needed to do geometry correctly. Once you have the correct length figured with the adjustable pushrod, you cut a full set of 8 to match it.
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Eric Allred
You have to remember something: Everybody pities the weak; Jealousy you have to earn. |
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Glenn
Mr. 010
Joined: December 25, 2001
Posts: 76939
Location: Sneaking up behind you
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| Posted: Tue Apr 07, 2009 5:01 pm Post subject: |
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This is why it's called "Custom".
Sorry.. it's never easy to do it right.
_________________
Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
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donny1973
Samba Member
Joined: November 21, 2008
Posts: 317
Location: Palm Beach, FL
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| Posted: Tue Apr 07, 2009 5:06 pm Post subject: |
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| Anyone need a new set of swivel adjusters? |
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perrib
Samba Member
Joined: September 14, 2004
Posts: 3402
Location: Chandler, Az
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| Posted: Tue Apr 07, 2009 7:11 pm Post subject: |
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| Selling them unless they are Empi won't fix anything. I alway trimmed an 1/8 inch from the bottom of the rocker. Even with lash caps you need to set the rocker geometry. |
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donny1973
Samba Member
Joined: November 21, 2008
Posts: 317
Location: Palm Beach, FL
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| Posted: Wed Apr 08, 2009 3:30 am Post subject: |
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| Shortening push rods and trimming rockers sounds too complex for me as a novice. Unless I know exactly what length push rods to order to make this work, I'm just going to get a new set of stock adjusters and go that way. |
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Randy in Maine
Samba Member
Joined: August 03, 2003
Posts: 34890
Location: The Beach
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Marv [UK]
Samba Member
Joined: January 07, 2009
Posts: 2225
Location: UK
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| Posted: Wed Apr 08, 2009 4:11 am Post subject: |
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| donny1973 wrote: |
| Shortening push rods and trimming rockers sounds too complex for me as a novice. Unless I know exactly what length push rods to order to make this work, I'm just going to get a new set of stock adjusters and go that way. |
Still won't work properly as you have a non standard cam
That is where the "problem" lies
Get an adjustable pushrod (only one is needed) and set your rocker geometry correctly, measure the adjustable rod length and order a set of custom push rods to that length |
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morymob
Samba Member
Joined: November 09, 2007
Posts: 4683
Location: east-tn
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| Posted: Wed Apr 08, 2009 6:11 am Post subject: |
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| U may have to add shims under rocker stands to get correct. |
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perrib
Samba Member
Joined: September 14, 2004
Posts: 3402
Location: Chandler, Az
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| Posted: Wed Apr 08, 2009 6:46 am Post subject: |
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| There is a very good post on setting rocker geometry in the stickies in this forum. |
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