|
Re: What is Proper Rocker Arm Geometry?
[Re: Monte_Smith]
#1685530
10/14/14 06:29 PM
10/14/14 06:29 PM
|
Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
|
I Win
Joined: Jan 2003
Posts: 32,394
|
Quote:
Quote:
my question is why even worry about it? I have never checked nor really give a flip if they are off a little. unless you are doing something very specific or searching for every bit of HP you can get what does it matter? there are thousands of motors built and last for a long period of time with no problems.
Thousands of motors out there running as well that never have the clearances checked either...........do you advocate that as well?
Are we building motors RIGHT......or are we just throwing them together and hoping for the best.........or are we just doing something in between.
Right is right.....half azz is half azz
Monte
call it what ever you want, mine seem to run prrety dang good and last for quite a while so I could care less.
|
|
|
Re: What is Proper Rocker Arm Geometry?
[Re: Quicktree]
#1685531
10/14/14 06:50 PM
10/14/14 06:50 PM
|
Joined: Nov 2004
Posts: 6,890
North Alabama
Monte_Smith
master
|
master
Joined: Nov 2004
Posts: 6,890
North Alabama
|
Quote:
Quote:
Quote:
my question is why even worry about it? I have never checked nor really give a flip if they are off a little. unless you are doing something very specific or searching for every bit of HP you can get what does it matter? there are thousands of motors built and last for a long period of time with no problems.
Thousands of motors out there running as well that never have the clearances checked either...........do you advocate that as well?
Are we building motors RIGHT......or are we just throwing them together and hoping for the best.........or are we just doing something in between.
Right is right.....half azz is half azz
Monte
call it what ever you want, mine seem to run prrety dang good and last for quite a while so I could care less.
Well carry on then......but no reason to tell everyone else it doesn't matter and they shouldn't care.
Monte
|
|
|
Re: What is Proper Rocker Arm Geometry?
[Re: Monte_Smith]
#1685532
10/14/14 07:35 PM
10/14/14 07:35 PM
|
Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
|
I Win
Joined: Jan 2003
Posts: 32,394
|
Quote:
Quote:
Quote:
Quote:
my question is why even worry about it? I have never checked nor really give a flip if they are off a little. unless you are doing something very specific or searching for every bit of HP you can get what does it matter? there are thousands of motors built and last for a long period of time with no problems.
Thousands of motors out there running as well that never have the clearances checked either...........do you advocate that as well?
Are we building motors RIGHT......or are we just throwing them together and hoping for the best.........or are we just doing something in between.
Right is right.....half azz is half azz
Monte
call it what ever you want, mine seem to run prrety dang good and last for quite a while so I could care less.
Well carry on then......but no reason to tell everyone else it doesn't matter and they shouldn't care.
Monte
i didn't tell anyone anything, look again i asked why. like I said it makes zero difference to me and most bracket racers. I could care lees if it's a .1 slower. it's obvious it has no bearing on longevity and I don't know very many bracket or index racers that bother with trying to find out if it's off or not. it's a pretty much given they are off.
|
|
|
Re: What is Proper Valvetrain Geometry?
[Re: clonestocker]
#1685533
10/14/14 08:43 PM
10/14/14 08:43 PM
|
Joined: Jan 2003
Posts: 1,290
Tucson AZ,
MadMopars
OP
pro stock
|
OP
pro stock
Joined: Jan 2003
Posts: 1,290
Tucson AZ,
|
I ran the car Saturday utilizing the "mid lift theory". I swapped back to my previous setup Saturday night with the intentions of testing again on Sunday. Unfortunately, I was sick on Sunday morning and was unable to return to the track. I concluded the performance loss from the other 100+ runs I have made with the car in similar conditions. Not ideal, but it is what is. I can go more in depth with weather specifics from comparative runs if need be. Regardless, loss of the effectiveness of a camshaft seems like a notable flaw that is very rarely mentioned. I personally will not be sweeping it under the rug. As such, I guess I was looking for opinions regarding the subject and how to find a middle ground. The more I research this subject though the more I think its either a big guarded secret or the majority are just plain happy not knowing. Since I think it's to late for me to go back to the latter of the two groups, if anyone has any input regarding optimal valvetrain geometry which also effectively utilizes the camshaft I certainly look forward to your input. 
|
|
|
Re: What is Proper Valvetrain Geometry?
[Re: MadMopars]
#1685534
10/14/14 10:17 PM
10/14/14 10:17 PM
|
Joined: Jan 2005
Posts: 2,540
Milwaukee WI
TRENDZ
master
|
master
Joined: Jan 2005
Posts: 2,540
Milwaukee WI
|
Quote:
Quote:
Has this been corroborated on a dyno, as in you KNOW you make less power or is the car just running a little slower ET.............Where on the track did it slow? Is it early, in the middle or on the top end. If the car runs the same speed it ran before, it makes the same power. You just may not be getting it down as consistently or as easily as you were before.
My point is that it seems hard for me to believe that MORE revs and better stability has cost you power
Monte
Monte,
The car slowed across the board, from 60' out the car was slower. The trap RPM and MPH were down as well.
The reason for this loss of performance in my opinion is this...
Valvetrain Geometry affects net lift at the valve as well as effective duration.
rocker geometry/pushrod length will change SPEED, stability, and lift at the valve, but not duration.(given the same lash settings)
You can "play" with fulcrum points to speed up or slow down off the seat velocity. You may have accidentally set up the engine originally with this "trick". You may have been using the engine in the range that the effects worked... and that's great. But now you've traded some of that speed for durability. You pay the toll on either side of the fence. 
"use it 'till it breaks, replace as needed"
|
|
|
Re: What is Proper Valvetrain Geometry?
[Re: TRENDZ]
#1685535
10/14/14 11:11 PM
10/14/14 11:11 PM
|
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
I Live Here
|
I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
|
There is no perfect rocker geometry for every situation. Maybe your valve train is stable enough you can change valve lift velocities to take advantage of head flow, if you heads flow real good up high you may get more power setting it up to get max velocity at peak valve lift and get a tiny extra lift but you can't do that if your valve train can't handle some weird harmonics you introduced. Maybe you heads flow real good at low lift, you may gain some power by setting the rockers to yank the valve off the seat faster, course it don't help if your valve starts bouncing because you close it too fast. You just got to experiment and figure out what works best on your combo. For most guys getting the roller center/shaft center/ PR pivot 90* at 1/2 lift will be close enough, for the last 1% of guys they need to do some experimenting on either side of that. Some times you want a RPM intake for best performance but sometimes you need the Super victor 
I am not causing global warming, I am just trying to hold off a impending Ice Age!
|
|
|
Re: What is Proper Valvetrain Geometry?
[Re: MadMopars]
#1685536
10/14/14 11:34 PM
10/14/14 11:34 PM
|
Joined: Mar 2006
Posts: 9,824
MI, usa
dvw
master
|
master
Joined: Mar 2006
Posts: 9,824
MI, usa
|
Quote:
Quote:
Has this been corroborated on a dyno, as in you KNOW you make less power or is the car just running a little slower ET.............Where on the track did it slow? Is it early, in the middle or on the top end. If the car runs the same speed it ran before, it makes the same power. You just may not be getting it down as consistently or as easily as you were before.
My point is that it seems hard for me to believe that MORE revs and better stability has cost you power
Monte
Monte,
The car slowed across the board, from 60' out the car was slower. The trap RPM and MPH were down as well.
The reason for this loss of performance in my opinion is this...
Valvetrain Geometry affects net lift at the valve as well as effective duration.
This is what is missing from many discussions regarding valvetrain geometry.
So by running less than optimal geometry you may have increased lift. If the performance loss wasn't due to conditions I would suggest you have the wrong cam. Why run the wrong geometry to increase lift and sacrifice stability and rpm range? Swaping a cam with proper duration, lift, LCA, and centerline would be a gain all around.
Doug
|
|
|
Re: What is Proper Valvetrain Geometry?
[Re: MadMopars]
#1685540
10/15/14 02:32 PM
10/15/14 02:32 PM
|
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
Taking time off to work on my car
|
Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
|
Quote:
I concluded the performance loss from the other 100+ runs I have made with the car in similar conditions. Not ideal, but it is what is. I can go more in depth with weather specifics from comparative runs if need be.
It would help to know how much of a performance loss you've seen and how much could be attributed to the changing atmospheric conditions. I've seen some pretty noticeable gains & losses due to that myself.
Quote:
... if anyone has any input regarding optimal valvetrain geometry which also effectively utilizes the camshaft I certainly look forward to your input.
My ... you probably have improved the valve train dynamics while reducing how aggressive the engine "saw" the cam. Now that you've addressed one potential issue, you can look into running different lobes to see about a performance improvement.
That's why you've got roller lobes designed for endurance applications that don't beat the sh!t outta the valve train and ultra-aggressive lobes that are designed to kick the valves open for more torque, yet require more spring load / limited RPM capabilities / increased maintenance schedules.
Like others have said, it's always a trade off. I don't know what else can be said about this.
|
|
|
Re: What is Proper Valvetrain Geometry?
[Re: Thumperdart]
#1685542
10/15/14 06:28 PM
10/15/14 06:28 PM
|
Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
|
I Win
Joined: Jan 2003
Posts: 32,394
|
Quote:
Quote:
I am surprised the geometry guru that popped up a few months ago hasn't jumped on this 
Maybe he`s sick of the "Experts" tellin him he`s crazy and doesn`t know what he`s talking about............ 
you must have not been paying attention. no one told him that they were getting on his case because he was trying to pimp his product. nice try though.
|
|
|
Re: What is Proper Valvetrain Geometry?
[Re: Quicktree]
#1685547
10/16/14 12:18 PM
10/16/14 12:18 PM
|
Joined: Jan 2003
Posts: 1,290
Tucson AZ,
MadMopars
OP
pro stock
|
OP
pro stock
Joined: Jan 2003
Posts: 1,290
Tucson AZ,
|
Quote:
here is my theory, at my level it is not significant enough to make a big difference. if some of you think it is give us some facts. like HP difference and dyno info/ life of the motor etc. I haven't seen anyone offering anything but unproven opinion. and yes I do visually check contact points through the motion but I have never worried about if the geometry is off a little. I am sure at high levels it becomes more crucial.
Just curious, in your opinion is .025 net lift loss significant? I ask because that's what I've lost by changing my geometry.
I also gain and or lose over 400 useable RPM in my shift points by changing the geometry.
Still not to worry about? 
|
|
|
|
|
