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koolkarmakombi
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PostPosted: Sat Apr 16, 2011 1:16 am    Post subject: Reply with quote

mark tucker wrote:
but but but, how does that work wont it just break off the end of the pushrod with it up in the rocker like that?? whay would thay machine the rocker like that? are they morons?? or just brain dammaged from falling offt the turnip truck andlanding on thier heads.
and it,s not just the valve end that matters . we are we having fun yet???a day from hell.


I **think** the geometry is done from the little cross points and the adjuster, rod and rocker are artistic representations and product may differ from illustration Wink
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mark tucker
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PostPosted: Sat Apr 16, 2011 7:06 am    Post subject: Reply with quote

yup I know I was just messen with doc.
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trainingman
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PostPosted: Wed Jul 27, 2011 4:28 pm    Post subject: Reply with quote

Image may have been reduced in size. Click image to view fullscreen.

Uploaded with ImageShack.us

this is how i set my rocker..........it's easy .......

when i see the same measure from the axle with magnet and the m8 bar when the valve is on the bottom and on the top i know about how many spacer i need under the rocker.......
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Oldbugr
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PostPosted: Wed Jan 18, 2012 6:45 am    Post subject: Reply with quote

Sorry for keeping this going, but this is my hurdle now. On page 6 of this thread, the picture 61bluebug posted with the wipe pattern slightly above centerline on the lash caps. Has anyone ran there motor with the wipe pattern like this? Does it really have to be in the center? I have tims stage 2 heads, cb's 1.4 rockers with now shims, FK8 cam and thats the best I can get. I don't have the tools to correctly take material from the rocker stand(head) or from the rocker block-which looks like a person would have to clearane the head stands even if you took material from the rocker blocks. Not sure if in the NW there is anyone how could machine things. So how in Calif, would I need to send what too? I'll be contacting tims today, as well as Pat Downs.
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mark tucker
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PostPosted: Wed Jan 18, 2012 8:45 am    Post subject: Reply with quote

do you have the cb lash caps? check to see if they are flat,I have had 4 or more sets where atleast 5 of them in each set were not flat, but domed, if so either get new ones(scat,empi,bugpack) oruse a wetrock on the fine side and flatten the dome off then polish,&use moly lube on them when assembling.
is that a full lift pattern?does it have lube on it?if it dont have lube on it or soft springs it can pull/push the valve and give a false pattern because it is not sliding/walking.I would probably go lower with the rocker.040 at a time.so if you had to you could still add a .015 shim or 2. the last set of those rockers I had needed about that much and the desine of the rocker it had good clearance on the bottom.any good machine shop should be able to mill the block all the same. they need to be checked to be sure that are all the same first. but if that is the true pattern yes it will work.
and the cb rockers have a little more raidi than some of the others out there.so the ratio should be close.good luck
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modok
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PostPosted: Wed Jan 18, 2012 5:32 pm    Post subject: Reply with quote

Oldbugr-
It seems most folks with the wipe pattern too high have 043 mexico heads
I suspect some of these heads have the rocker studs too close to the valves

To correct this the rocker studs can be moved or the rockers reground, unfortunately, most folks do not have the tools to do it
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Oldbugr
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PostPosted: Wed Jan 18, 2012 6:37 pm    Post subject: Reply with quote

Glenn, My tims heads are the 043 heads, I've had them since july of last year. I talked to Pat downs, he was pretty busy so he wasn't very helpful. I spoke with Steve tims today and I'm going to be sending the heads to him and he'll shave off what ever I want. He mentioned he shaves off .100 for guys all the time. One thing thats weird to me and I assume it's my dial indicator mount or the rockers, is the inconsistancy of the readings I get. I'm checking only the 1 & 2 side right now, total spring movement=
1I=542
1E=544
2I=557
2E=550
Checking with no shims, and the same length pushrod for all of the measurments. I might swap rockers around and see if I get different readings.
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modok
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PostPosted: Wed Jan 18, 2012 6:55 pm    Post subject: Reply with quote

THe closer you look the more you see
That variance is not huge, but it would be interesting to know what causes it

Do you have another stock head, or a stock rockershaft, or a 44mm valve to use to compare?
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Oldbugr
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PostPosted: Wed Jan 18, 2012 7:11 pm    Post subject: Reply with quote

I do have a set of 1.25 rockers that I pulled off, I might check them. Thanks for the thought.
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x-file
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PostPosted: Tue Mar 13, 2012 6:56 pm    Post subject: Reply with quote

Desertbusman wrote:
What NSracing says about geometry is true. The greatest bad forces working on the valve tips is at the highest lift and spring pressure. towards that highest lift is when you want the adjusters to be pushing straight down on the valve with less side pressure.


WITH FEW EXCEPTIONS,THE CONCEPTS of "GOOD GEOMETRY" AND SIDE-THRUST ON GUIDES in this thread are WRONG.THIS IS JUST ONE INCORRECT CONCEPT.It is only true at zero rpm.
At high rpm (close to valve-float),there isn't much load on the valve-tip at full lift.The valve reached full velocity at about 0.100" lift,and since then most of the spring load has been used trying to decelerate the moving valve and accelerate it in the opposite direction.Some of the spring load is used to decelerate the rest of the valve-train.There is almost no spring load on the cam lobe at full lift.(That's why you bed a cam in above 2000 rpm).
The big forces are happening at the start and finish of lift,where the cam acceleration is about 3-1/2 times as much.So the valve-tip can see about 4 times as much load at low lift as it does at full lift.It's all to do with inertia and acceleration.

This is where zero-scrub and zero side-thrust at mid angular swing or mid-lift (which aren't necessarily the same point) falls down and isn't ideal.
*Zero side thrust at 1/3-lift would be OK for a daily driver.1/3 to 1/2 lift would do.This is normal stuff;it's even called "The 1/3 Rule" for non-roller rockers.
*Zero side thrust at 20% lift or even less would be OK for a racer.This gives only small side thrust at the highly loaded opening and closing at high rpm.

THE ANGLE OF AN ADJUSTER SCREW DOES NOT CONTROL SIDE-THRUST.

THE CONTACT POINT ON THE VALVE-TIP (CENTRAL OR OTHERWISE), DOES NOT CONTROL SIDE-THRUST.

The angle of an adjuster and central contact on the valve-tip may look good at zero side-thrust,if the rocker was well designed for your exact engine and purpose.

THE VALVE-SIDE OF THE ROCKER ARM MUST BE SET UP RIGHT,TO AVOID SIDE-THRUST ON VALVES AND STEMS.You can only do this by adjusting valve length or rocker-shaft height.Worry about pushrod length when the valve side of the rocker is right.
There are 3 basic types of rocker arm (on the valve-side),and they suit different geometry.

*Roller rocker:Look at Jim Miller's "Mid-Lift" setup.In a perfect world,there would be no side-thrust with a roller rocker,but there is inertia and friction in the real world.

*Solid rocker,either with solid (one-piece) adjuster screw or with shoe/pallet contact face:
Zero scrub and side-trust occurs when a line taken from the valve-tip or lash-cap through the centre of the rocker shaft IS SQUARE TO THE VALVE-STEM.
This happens to be an accident of geometry;at that instant,the radius on the rocker tip is rolling across the valve away from the rocker shaft at the same rate it's centre is moving toward the valve-stem axis.The bigger the radius,the more it rolls either side of valve centre.

*Swivel-ball or elephant's foot :
Zero scrub and side-thrust occur when a line taken from the centre of the pivot ball through the rocker shaft centre IS SQUARE TO THE VALVE STEM. There is no rolling action,and the contact point on the valve-tip doesn't move far.It moves away from the shaft at the start of lift,and back toward the shaft at full lift.There is more contact area than a solid rocker,and less wear.
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mark tucker
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PostPosted: Tue Mar 13, 2012 7:41 pm    Post subject: Reply with quote

I think millers system was discontinued.there are many different ways to set them up and many different ways to make the rocker "work" better, and many different shapes of the rocker that affects the valve timing.most all roller rockers dont roll but skid,but if it,s a good rocker it should not pull or push the valve, but it can pull or push instead of rolling. The major amount of roller rockers on the market dont have any thing but a axle and a roller.some jessel&t&d you can get with real roller bearings in the tip end and they do a lot better job,but there nice&pricey.titin has a very good system out, but I doubt they make them for vw.theres is a quick lift type and makes hp.
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ekacpuc
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PostPosted: Tue Mar 13, 2012 11:30 pm    Post subject: Reply with quote

So the shims under the rockers adjust how high the contact patch is on the valve stem right?

The adjustable pushrod controls the relation of the adjuster screw to the valve stem right? As in it sorta tilts the adjuster screw...

What does the side to side? Shims on the side of the rocker arms?


Greg
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66brm
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PostPosted: Wed Mar 14, 2012 12:37 am    Post subject: Reply with quote

Yes
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modok wrote:
I am an expert at fitting things in holes, been doing it a long time
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ekacpuc
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PostPosted: Wed Mar 14, 2012 4:51 am    Post subject: Reply with quote

Wow great thread! I had no idea until I read and saw all the pictures. I knew the steps but not what I was lookin for.

Cool,
Greg
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Beetspeed
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PostPosted: Sun Mar 18, 2012 3:17 pm    Post subject: Reply with quote

x-file wrote:
Desertbusman wrote:
What NSracing says about geometry is true. The greatest bad forces working on the valve tips is at the highest lift and spring pressure. towards that highest lift is when you want the adjusters to be pushing straight down on the valve with less side pressure.


WITH FEW EXCEPTIONS,THE CONCEPTS of "GOOD GEOMETRY" AND SIDE-THRUST ON GUIDES in this thread are WRONG.THIS IS JUST ONE INCORRECT CONCEPT.It is only true at zero rpm.
At high rpm (close to valve-float),there isn't much load on the valve-tip at full lift.The valve reached full velocity at about 0.100" lift,and since then most of the spring load has been used trying to decelerate the moving valve and accelerate it in the opposite direction.Some of the spring load is used to decelerate the rest of the valve-train.There is almost no spring load on the cam lobe at full lift.(That's why you bed a cam in above 2000 rpm).
The big forces are happening at the start and finish of lift,where the cam acceleration is about 3-1/2 times as much.So the valve-tip can see about 4 times as much load at low lift as it does at full lift.It's all to do with inertia and acceleration.

This is where zero-scrub and zero side-thrust at mid angular swing or mid-lift (which aren't necessarily the same point) falls down and isn't ideal.
*Zero side thrust at 1/3-lift would be OK for a daily driver.1/3 to 1/2 lift would do.This is normal stuff;it's even called "The 1/3 Rule" for non-roller rockers.
*Zero side thrust at 20% lift or even less would be OK for a racer.This gives only small side thrust at the highly loaded opening and closing at high rpm.

THE ANGLE OF AN ADJUSTER SCREW DOES NOT CONTROL SIDE-THRUST.

THE CONTACT POINT ON THE VALVE-TIP (CENTRAL OR OTHERWISE), DOES NOT CONTROL SIDE-THRUST.

The angle of an adjuster and central contact on the valve-tip may look good at zero side-thrust,if the rocker was well designed for your exact engine and purpose.

THE VALVE-SIDE OF THE ROCKER ARM MUST BE SET UP RIGHT,TO AVOID SIDE-THRUST ON VALVES AND STEMS.You can only do this by adjusting valve length or rocker-shaft height.Worry about pushrod length when the valve side of the rocker is right.
There are 3 basic types of rocker arm (on the valve-side),and they suit different geometry.

*Roller rocker:Look at Jim Miller's "Mid-Lift" setup.In a perfect world,there would be no side-thrust with a roller rocker,but there is inertia and friction in the real world.

*Solid rocker,either with solid (one-piece) adjuster screw or with shoe/pallet contact face:
Zero scrub and side-trust occurs when a line taken from the valve-tip or lash-cap through the centre of the rocker shaft IS SQUARE TO THE VALVE-STEM.
This happens to be an accident of geometry;at that instant,the radius on the rocker tip is rolling across the valve away from the rocker shaft at the same rate it's centre is moving toward the valve-stem axis.The bigger the radius,the more it rolls either side of valve centre.

*Swivel-ball or elephant's foot :
Zero scrub and side-thrust occur when a line taken from the centre of the pivot ball through the rocker shaft centre IS SQUARE TO THE VALVE STEM. There is no rolling action,and the contact point on the valve-tip doesn't move far.It moves away from the shaft at the start of lift,and back toward the shaft at full lift.There is more contact area than a solid rocker,and less wear.

Awesome post and very well summerised!
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disneymike
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PostPosted: Sun Mar 18, 2012 5:50 pm    Post subject: Reply with quote

Ok teachers, I have a question. I have .060 shims under my Bugpack 1.4 rockers (FK8 cam). The wipe pattern is good and I have got the adjustable pushrod right where at half lift the pushrod and the adjuster are lined up. My questions is I am only reading .512 total lift when the FK8 with 1.4's should be around .534 according to the cam card. What am I doing wrong?
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PostPosted: Sun Mar 18, 2012 9:21 pm    Post subject: Reply with quote

disneymike wrote:
Ok teachers, I have a question. I have .060 shims under my Bugpack 1.4 rockers (FK8 cam). The wipe pattern is good and I have got the adjustable pushrod right where at half lift the pushrod and the adjuster are lined up. My questions is I am only reading .512 total lift when the FK8 with 1.4's should be around .534 according to the cam card. What am I doing wrong?


Sounds like the .060 shim..........
with no shims...
find zero lift on the valve, adjust the adjuster 3/4 turns in, adjust pushrod to take up slack in lash, run it through........
check your wipe ...where is it? high? low?

the head stud trick really helps you get it all lined up
Image may have been reduced in size. Click image to view fullscreen.
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disneymike
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PostPosted: Mon Mar 19, 2012 5:04 pm    Post subject: Reply with quote

MURZI wrote:
disneymike wrote:
Ok teachers, I have a question. I have .060 shims under my Bugpack 1.4 rockers (FK8 cam). The wipe pattern is good and I have got the adjustable pushrod right where at half lift the pushrod and the adjuster are lined up. My questions is I am only reading .512 total lift when the FK8 with 1.4's should be around .534 according to the cam card. What am I doing wrong?


Sounds like the .060 shim..........
with no shims...
find zero lift on the valve, adjust the adjuster 3/4 turns in, adjust pushrod to take up slack in lash, run it through........
check your wipe ...where is it? high? low?

the head stud trick really helps you get it all lined up
Image may have been reduced in size. Click image to view fullscreen.


Ok, with your help, I believe I got it. Total lift is .525 - no shims with wipe pretty much centered. This is at half lift:

Image may have been reduced in size. Click image to view fullscreen.[/img]
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MURZI
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PostPosted: Mon Mar 19, 2012 7:21 pm    Post subject: Reply with quote

One other ting I failed to mention.....I had to take about 1/8" off my adjustable pushrod to allow proper geometry. It looks like yours could be shortened a bit as well.

And you are running lash caps huh??
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PostPosted: Mon Mar 19, 2012 7:39 pm    Post subject: Reply with quote

MURZI wrote:
One other ting I failed to mention.....I had to take about 1/8" off my adjustable pushrod to allow proper geometry. It looks like yours could be shortened a bit as well.

And you are running lash caps huh??


Yes, running lash caps. Due to the crappy pic I do have some adjustment left on the adjustable PR. I'm pretty happy with what I have on the 1/2 side. Now on to the 3/4 side..... Wink

Once again, thanks for the help MURZI! One day this engine will actually start up!
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