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Quokka42
Samba Member
Joined: December 02, 2010
Posts: 3117
Location: Melbourne, Australia
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 Posted: Sun Nov 09, 2014 3:38 am Post subject: |
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Yes, but a greater force on a shorter lever can produce the same effect (as the spring is compressed,) plus you may end up only producing that force in one direction as VWs were designed to have an even scrub across the valve. Add in the aforementioned ratio error that is introduced and you are starting to wander off into No Man's Land. BTW, the leverage only applies to the top of the guide, while the whole guide carries the load.
Chev V8s are a whole different animal, and the suggested method is appropriate at least - actually highly recommended.
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mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Sun Nov 09, 2014 9:20 am Post subject: |
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| hmm, a valve,a guide,a rocker arm,force.....chevy,ford,mopar,vw all seem to have the same things incommon and all kill guides & valves when not setup properly. the more ratio the less affect of scrub back&forth. And it is the pivot length that changes and makes it better.the more pivot length the better. weather it is a chevy or vw makes no diff,just vw chose to use a shity rocker ratio and many have decided this is the best because somebody long ago said so and vw did it.and it just keeps getting repeated by the repeaters.(those are the opnes that dont have a clue about anything execpt for searching old outdated crap are repeating it assureing us it is the only way to go.) |
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heimlich 
VWNOS.com
Joined: November 20, 2016
Posts: 6598
Location: Houston, Texas
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| Posted: Tue Feb 28, 2017 7:50 am Post subject: Re: Rocker Geometry |
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| What's a good dial indicator to buy that won't break the bank? I need to do rocker arm shims. |
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mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Tue Feb 28, 2017 10:00 am Post subject: Re: Rocker Geometry |
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most any are good these days,(china is cheep,usa is expensive. they both work.I have a wore out sterret, but no wore out china...and I have a lot of china indacators just because of the price and drop laugh or cry factor that all read the same. but what are you gonna do with a dial indacator & rocker arm geo?  |
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heimlich
VWNOS.com
Joined: November 20, 2016
Posts: 6598
Location: Houston, Texas
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| Posted: Tue Feb 28, 2017 10:30 am Post subject: Re: Rocker Geometry |
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| mark tucker wrote: |
| most any are good these days,(china is cheep,usa is expensive. they both work.I have a wore out sterret, but no wore out china...and I have a lot of china indacators just because of the price and drop laugh or cry factor that all read the same. but what are you gonna do with a dial indacator & rocker arm geo? |
I put new stock heads in my engine. I am told I need to possibly shim them. I am trying to figure that out. I see some posts on this thread using a dial indicator so I figure I would need that. The next step is to figure out the steps and hopefully I can do that from this site, my Hayes, Wilson, Bentley, and Muir books. |
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mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Tue Feb 28, 2017 10:50 am Post subject: Re: Rocker Geometry |
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| no not realy, no indicator required. mostly eyeballs, a soft spring replacing the valve spring,, adjustable pushrod.and a marker. and possiably the rockers ground down/machined down some depending on the type of rocker you have. lash caps is also a great thing to have on them too. |
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nogoodwithusernames
Samba Member
Joined: November 10, 2014
Posts: 599
Location: CA, USA
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heimlich
VWNOS.com
Joined: November 20, 2016
Posts: 6598
Location: Houston, Texas
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| Posted: Tue Feb 28, 2017 11:45 am Post subject: Re: Rocker Geometry |
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| mark tucker wrote: |
| no not realy, no indicator required. mostly eyeballs, a soft spring replacing the valve spring,, adjustable pushrod.and a marker. and possiably the rockers ground down/machined down some depending on the type of rocker you have. lash caps is also a great thing to have on them too. |
I bought the heads new so I wouldn't have to mess with them. I would need to do that to "replace the valve spring", yes? Also, I did not buy adjustable push rods. I bought the stock ones. I also have a stock rocker. |
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Boolean
Samba Member
Joined: January 19, 2012
Posts: 1712
Location: Stockholm
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Max Welton
Samba Member
Joined: May 19, 2003
Posts: 10697
Location: Black Forest, CO
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mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Tue Feb 28, 2017 7:15 pm Post subject: Re: Rocker Geometry |
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| the adjustable oushrod is just for checking and deermaning the needed pushrod size. if you already have everything assemble it and see how the geo is., be aware 1.25 rockers usualy need big mouth pushrod tubes or the pushrod will contact the pushrod tube and kill the pushrod and possiably the case too. so you need to check for clearance on all 8 at all positions of the lift cycle. |
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fivelugshortaxle
Samba Member
Joined: May 13, 2011
Posts: 4254
Location: Aumsville, Oregon
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| Posted: Wed Nov 22, 2017 1:00 am Post subject: |
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| nsracing wrote: |
| vwcalbug wrote: |
build the engine up, and use the adjustable pushrod to get them at half lift...let the valve train do the work....
-JustinD |
Oh yea sure. The adjustable will probably bend like a copper wire.
You were supposed to mock up the motor only with light springs to set the rocker geometry. What happens now if you find out that you do not have correct piston to valve clearance after you find the right geometry??? 
If this is a stroker motor with high compression...deep flycuts..and high lift cam, you can bet you will need some piston valve reliefs to clear the valves.
It is very hard to get the rocker geometry work up after you have already final assembled the motor. Now you have to find some very stiff push rods to do this mock up in close enough length so you can figure out the final lenght.
YOu can remove the springs and install light ones. There is this tool that was factory to change weak springs while the heads are installed.
I just use the Type IV rocker springs..yea the skinny ones. I install them in the mock-up stage and check full rocker geometry movement and at the same time see piston to valve interference. See how long the push rod has to be for the correct attitude, and move the intake valve to full lift with the piston at TDC. Install a dial indicator and push on the intake valve by hand. Watch the depth of the dial indicator...this will be your clearance. Add the reliefs accordingly.
Good luck man. |
Just saw this and thought it was funny. Did my geo with duals. 650 duals. Adjustable pushrods stayed perfectly straight. No flex.
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2332 with lots of goodies....
Rotating assembly balanced by Brothers VW
4340 84mm crank
AA 94mm p&c' s
Total seal 2nd ring, rest are Grants
5.5 h beams
Magnum straight cuts
Steve Long XR310 on a 106
CB 1.4 rockers
CB Magnaspark 2 distributor
NGK D7ea plugs
A1 lowdown 1 3/4 with single muffler
Dellorto 48's with 40 venturies
Kennedy Stage 2 with Daiken disc |
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fivelugshortaxle
Samba Member
Joined: May 13, 2011
Posts: 4254
Location: Aumsville, Oregon
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| Posted: Wed Nov 22, 2017 1:02 am Post subject: |
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| mark tucker wrote: |
| hmm, a valve,a guide,a rocker arm,force.....chevy,ford,mopar,vw all seem to have the same things incommon and all kill guides & valves when not setup properly. the more ratio the less affect of scrub back&forth. And it is the pivot length that changes and makes it better.the more pivot length the better. weather it is a chevy or vw makes no diff,just vw chose to use a shity rocker ratio and many have decided this is the best because somebody long ago said so and vw did it.and it just keeps getting repeated by the repeaters.(those are the opnes that dont have a clue about anything execpt for searching old outdated crap are repeating it assureing us it is the only way to go.) |
Hahahaha...this about sums it up. "If vw thought it would be better they would have done it that way." Hahahaha
_________________
Good things come to those who wait.
2332 with lots of goodies....
Rotating assembly balanced by Brothers VW
4340 84mm crank
AA 94mm p&c' s
Total seal 2nd ring, rest are Grants
5.5 h beams
Magnum straight cuts
Steve Long XR310 on a 106
CB 1.4 rockers
CB Magnaspark 2 distributor
NGK D7ea plugs
A1 lowdown 1 3/4 with single muffler
Dellorto 48's with 40 venturies
Kennedy Stage 2 with Daiken disc |
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calvinater
Samba Member
Joined: September 06, 2014
Posts: 3328
Location: 802 The Pointless Forrest
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| Posted: Mon Mar 12, 2018 8:50 am Post subject: Re: Rocker Geometry |
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Mr Tucker , you never told us what the marker was for.
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APPLEGREENVW
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Joined: November 30, 2003
Posts: 2387
Location: Seekonk,Massachusetts USA
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calvinater
Samba Member
Joined: September 06, 2014
Posts: 3328
Location: 802 The Pointless Forrest
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| Posted: Mon Mar 12, 2018 5:02 pm Post subject: Re: Rocker Geometry |
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got it thanks
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mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Tue Mar 13, 2018 6:38 am Post subject: Re: Rocker Geometry |
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sorta kinda but not. just looking at marker marks don't tell you squat if you didn't see ehats going on or of the rocker wasent sliping or was...and how do you tell if the marker mark was going up ward or downward....I also may disagree about half lift...and low lift...
what if your rocker pushed this then that way it can leave a great pattern, but it's false. marker is no substitute for eyes&brains. it can however tell you if the rocker if flat on the valve end/same angle side to side....if you don't have too much spring pressure when checken |
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Clatter
Samba Member
Joined: September 24, 2003
Posts: 7537
Location: Santa Cruz
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| Posted: Thu Mar 15, 2018 11:44 am Post subject: Re: Rocker Geometry |
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I love this thread.. Should be made into a sticky!
Here, we have wisdom of many kinds, from the late, great Robert S Hoover.. RIP.
'mark tucker' and Nick Sison are (along with supposedly NASCAR) saying that you should have right angles at full lift?
Everybody else (Gene Berg Jake Raby etc.) always preached right angles at half-lift..
And now here comes another user 'x-file' making a dman good case for far before 1/2 lift..!
There's as many methods as there are carpenters...
I love this bar!
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Clatter
Samba Member
Joined: September 24, 2003
Posts: 7537
Location: Santa Cruz
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| Posted: Thu Mar 15, 2018 11:53 am Post subject: |
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| Bob Hoover wrote: |
| Desertbusman wrote: |
| .... The bad situation is getting advice from those that don't know what they are talking about. . |
When it comes to VOLKSWAGEN valve train geometry, bad advice is virtually guaranteed, especially from all those 'experts.' With a horizontally-opposed engine you have to start at the parting-line and work out. You can't assume the crank & cam bores are precisely on the center-line, nor that the decks are of equal height. Any error here -- and I've seen up to sixty-thou on a poorly overhauled crankcase, gets built-in.
Ditto for cam-lift. Base-circle to peak may be fine for an individual lobe but the ACTUAL lift is based on the center-line of the cam, which can be a few thou off IN ANY DIRECTION, especially on cheap, after-market cams. Then comes dialing in the cam. Even with all stock parts ithe assemblage can be off as much as +/- 4 degrees, which is why Volkswagen provided offset Woodruff keys to adjust the frequent stack-up errors that occur in serial production. Then they provide NINE different sizes of cam gear to ensure proper mesh & timing.
Only when you've done all that basic work, ensuring you have an accurate lower-end, can you address compression ratio and valve train geometry. But by that time all the 'experts' are telling the newbies that none of that 'techy' stuff matters. And the odds are, most of the newbies will agree.
My point here is that there really isn't much a professional engine-builder can do for a newbie trying to line-up his rocker arms because not one in a thousand has done the required foundation work and most don't even have the necessary tools. Plus you have all those Instant Experts who have never done any of that stuff and their ONE engine runs jus' fine. Of course, you never seem to find any of those 'experts' at the finish line getting a champagne shampoo. Nor the flight line, celebrating a thousand trouble-free hours of flight in their RF-4D.
What you DO see is a lot of instant experts passing out bum dope by the bucketful, parroting procedures meant for water-cooled, mono-block engines that address only the OUTPUT-side of the geometry equation. In the water-cooled world the INPUT-side of the valve train geometry equation almost never changes, unless they deck the block or mill the heads more than .040. But when you build a veedub from after-market components, you've got to start at Ground Zero.
It should come as no surprise that trannies and differentials get the same treatment by all those instant experts. Indeed, newbies WANT to believe all the Quick & Easy myths, and after all, the thing DOES run. Since the odds of having to go head-to-head with a properly built engine are about the same as for finding lips on a chicken, the newbies are happy (for a while at least) and the Instant Experts give themselves another pat on the back.
Hell of a good joke, when you think about it 
-Bob Hoover |
The Man was a genius..
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daos
Samba Member
Joined: January 01, 2017
Posts: 309
Location: Stockholm, SWE
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| Posted: Wed Aug 12, 2020 1:38 am Post subject: Re: Rocker Geometry |
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currently setting up my rockers, tried a number of shims from zero up to 3.6mm. some images here to show 0, 1.8 and 3.6:
seems like the various shims are not making a huge amount of difference to the swipe pattern which moves only slightly. 0 shims are looking the best so far (closest to the centre of the valve stem). they also give the straightest relation between adjuster and pushrod at half lift.
the swipe pad is contacting the valve stem on the heel of the pad (lower half nearest the rocker shaft), doesn't swipe beyond halfway. not sure how crucial that is.
not worried about left-right position, will adjust that with rocker shaft shims.
there is a lot of info on setting up traditional/elephant adjusters, but not so much on the swipe versions. am i looking for the same perpendicular relationship between contact point axis and shaft centre as with the non-swipe rockers?
also more shims seems to move the swipe pattern up the valve instead of down, shouldn't it be the other way around? |
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