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Re: Rocker Geometry Measurements
[Re: all spooled up]
#1524357
10/29/13 08:01 PM
10/29/13 08:01 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
Posts: 32,394
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Quote:
chased off a nuter one     
well if he is not man enough to stick around and explain a few things no big loss.
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Re: Rocker Geometry Measurements
[Re: B3RE]
#1524359
10/29/13 09:25 PM
10/29/13 09:25 PM
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Joined: Jan 2003
Posts: 6,591
Canton, Ohio
Sport440
master
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master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
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Quote:
Here are the measurement and spec instructions, required for calculating correct geometry, that so many of you have requested.
1. Distance between the top of the rocker shaft and the top of the valve stem. Measure the distance between the combination square and the tip of the valve stem using a caliper, feeler gages, or other accurate measuring device. Be sure the square is resting on top of the rocker shaft and the blade is on the same angle as the valve stem. (See Photo)
2. Diameter of the rocker shaft and the roller tip of the rocker arm.
3. Rocker ratio being used.
4. Valve lift from cam card w/ 1.5 ratio rocker, or just lobe lift.
With these measurements and specs, you can contact me and I can let you know if correction is necessary, and supply you with the appropriate kit to make it perfect, guaranteed.
As always, I am happy to answer questions. I like questions.
Im not here to scare anybody.
But I believe the above requested info isnt enough to figure out anybodys rocker geometry.
IMO, one would also need to know the relationship between the "Roller tip and the Rockers body", along with the variable pushrod side of that Rocker.
As in, at a 90* angle to the valve is the roller center in the rocker body parrallel with the shafts center or is it offset up or down from that center.
Without knowing that, IMO, A absolute Geometry cant be figured out. Would I be correct?? 
Also, is absolute geometry really needed, for most purposes Im going to assume the rocker manufactures have it really close to begin with.
No doubt IMO, a really tight sweep of the roller tip is a good indicater of good geometry. 
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Re: Rocker Geometry Measurements
[Re: Sport440]
#1524360
10/29/13 10:04 PM
10/29/13 10:04 PM
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Joined: Oct 2005
Posts: 8,905
Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,905
Ontario, Canada
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Quote:
Also, is absolute geometry really needed, for most purposes Im going to assume the rocker manufactures have it really close to begin with.
Really ?!?! You were sounding pretty smart for a while there but you've just dispelled that notion.
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Re: Rocker Geometry Measurements
[Re: Stanton]
#1524362
10/29/13 10:18 PM
10/29/13 10:18 PM
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Joined: Jan 2003
Posts: 6,591
Canton, Ohio
Sport440
master
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master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
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Quote:
Quote:
Also, is absolute geometry really needed, for most purposes Im going to assume the rocker manufactures have it really close to begin with.
Really ?!?! You were sounding pretty smart for a while there but you've just dispelled that notion.
I hear you, but Im referring to the word "Absolute" Im sure many of us dont have it with our rocker arm/shaft/valve combos.
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Re: Rocker Geometry Measurements
[Re: Sport440]
#1524363
10/29/13 11:09 PM
10/29/13 11:09 PM
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Joined: Jan 2003
Posts: 31,069
Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 31,069
Oregon
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I think that most of the mfgs do a decent job figuring out the rocker arm geometry. The problem is that they don't tell people what the assumptions are behind the designs. Some rocker arms are designed to be stock replacements, some as race parts, some for stock heads, etc.
I spent my own money years ago to buy one rocker arm from every mfg possible so I could do my own measurements. I gradually figured out which arms worked with which heads and what lift ranges but it was a bit of a painful process.
I used to sell these rocker sweep tools. They do a good job of providing an engine builder with an actual number for the sweep. Without an actual measurement you're just kind of guessing at the results of a geometry change.
I've looked at the system that the OP sells and it doesn't make any sense to me. Maybe it works, maybe it doesn't. I'm not going to buy one to test out. I'll let someone else do that job. I've tested enough parts over the years!
Last edited by AndyF; 10/29/13 11:10 PM.
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Re: Rocker Geometry Measurements
[Re: Crizila]
#1524364
10/30/13 01:35 AM
10/30/13 01:35 AM
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Joined: Jun 2005
Posts: 6,257
gulfport, ms, west mi
rowin4
master
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master
Joined: Jun 2005
Posts: 6,257
gulfport, ms, west mi
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Looking at the add pictures that he has on craigslist, it seems that the heads need machining for the shims to be installed. Looks like the shims themselves are ground offset in the picture to correct the geometry., but the heads need machining to do that as you can't put that thick of a shim under the shaft without splitting the shaft mount. Or you could use a smaller shaft, but that would require special rockers to replace the ones that are off. As for the bolt /studs in aluminum heads, I bought my ARP rocker shaft studs from Magnum for my Edelbrock RPM's 440 heads.
it's ok to butt heads, just don't do it with a butthead
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Re: Rocker Geometry Measurements
[Re: rowin4]
#1524365
10/30/13 08:59 AM
10/30/13 08:59 AM
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Joined: Jul 2008
Posts: 361
Canada
onig
enthusiast
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enthusiast
Joined: Jul 2008
Posts: 361
Canada
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This topic is very interesting as I am going through this process with a Pontiac stud rocker system. I have been doing some research to understand the theory.
The kit that B3RE sells will work. Those "shims/spacers" are machined to raise the shaft up the required amount to achieve the 90* angle to the valve at half lift. He also can move the shaft to the inside or outside if needed. From what I know each kit is custom made to your application from the specs that you give him.
I think that a lot of people will change rockers and not check for proper geometry. I used to think that proper geometry was having the roller centered on the valve, but not any more after looking into this somewhat.
Onig
69 Dart
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Re: Rocker Geometry Measurements
[Re: onig]
#1524366
10/30/13 09:55 AM
10/30/13 09:55 AM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
Posts: 32,394
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Quote:
This topic is very interesting as I am going through this process with a Pontiac stud rocker system. I have been doing some research to understand the theory.
The kit that B3RE sells will work. Those "shims/spacers" are machined to raise the shaft up the required amount to achieve the 90* angle to the valve at half lift. He also can move the shaft to the inside or outside if needed. From what I know each kit is custom made to your application from the specs that you give him.
I think that a lot of people will change rockers and not check for proper geometry. I used to think that proper geometry was having the roller centered on the valve, but not any more after looking into this somewhat.
Onig
I think everyone will agree with that. a different approach would have went over a lot better.
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Re: Rocker Geometry Measurements
[Re: CHAPPER]
#1524368
10/30/13 10:56 AM
10/30/13 10:56 AM
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Joined: Jan 2003
Posts: 6,354
Aurora, Oh.
max_maniac
master
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master
Joined: Jan 2003
Posts: 6,354
Aurora, Oh.
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Quote:
Quote:
heck i would just like him to introduce himself
Maybe you should try one of the online dating sites,,,he's not the only guy out there.  
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Re: Rocker Geometry Measurements
[Re: max_maniac]
#1524369
10/30/13 11:08 AM
10/30/13 11:08 AM
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Joined: Oct 2005
Posts: 8,905
Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,905
Ontario, Canada
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Quote:
Quote:
heck i would just like him to introduce himself
Maybe you should try one of the online dating sites,,,he's not the only guy out there.
LMAO !!!
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Re: Rocker Geometry Measurements
[Re: CHAPPER]
#1524370
10/30/13 12:14 PM
10/30/13 12:14 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
Posts: 32,394
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Quote:
Quote:
heck i would just like him to introduce himself
Maybe you should try one of the online dating sites,,,he's not the only guy out there.
I am sure your homo friends will get a laugh out of that
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