Rocker to valve tip contact - your opinion?
#2105238
07/06/16 08:32 PM
07/06/16 08:32 PM
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Joined: Jan 2003
Posts: 1,797 Windsor, ON, Canada
Diplomat360
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top fuel
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OP
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Windsor, ON, Canada
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Alright....so the freshened up heads are now back on my 360 block, next step is to check the pushrod lengths. I am using 1.5 ratio roller rocker arms now, great pieces, no complaints. But, I do have the 1.6 ratio Crane ductile iron ones and truth be told I've been itching to try them out. So here are some pics of the rocker arm "nose" to valve-tip alignment scenarios. I'm looking for feedback regarding what is considered to be the best/recommended choice. Since I used rocker arm shaft shims here that will impact the pushrod length, so I want to get this right. Here we go: 1) the current roller rockers, the actual roll contact pattern itself is literally perfect, dead smack in the middle of the valve-tip 2) same as above but with the use of a valve-stem cap, just for comparison pursposes, I do not use them today but given the move to non-rocker arms I'm considering their use 3) 1.6 ratio arms with no shim 4) 1.6 ratio rockers with no shim and with cap 5) 1.6 ratio arms with 0.040" shim 6) 1.6 ratio rockers with 0.040" shim and cap I have the 0.020" shims as well, but I think the 0.040" is the most I would need. To me it looks like the 0.040" stuff gives the best alignment. The non-roller rocker will swipe across the valve-stem and therefore I'm looking to start slightly off-center and finish slightly off-center. But heck, tell me if I'm wrong here... Thanks!
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Re: Rocker to valve tip contact - your opinion?
[Re: DARTH V8Я]
#2105328
07/06/16 10:41 PM
07/06/16 10:41 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
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Posts: 36,041
Lincoln Nebraska
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those are valve closed pics. I would post the same choices/options at full lift to see the sweep across the valve stem tip
live every 24 hour block of time like it's your last day on earth
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Re: Rocker to valve tip contact - your opinion?
[Re: RapidRobert]
#2105342
07/06/16 11:08 PM
07/06/16 11:08 PM
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Joined: Jan 2003
Posts: 1,797 Windsor, ON, Canada
Diplomat360
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those are valve closed pics. I would post the same choices/options at full lift to see the sweep across the valve stem tip Oh believe me, I would love to do that...but these pics were taken with the head sitting on my bench, before I tossed it back on the short-block, which is in the car...LOL...so, no way can I get that good of a pic with the stuff assembled, just no room to place my DSLR camera in there...grrhh...
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Re: Rocker to valve tip contact - your opinion?
[Re: Diplomat360]
#2105362
07/06/16 11:34 PM
07/06/16 11:34 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
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Lincoln Nebraska
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what about a light spring (I'm assuming it ain't running yet) opened to gross lift dimention & just a visual on your choices & see which one gives the least sweep area/closest to center (or just turn the dampener as is if the long block is all together) to max lift
live every 24 hour block of time like it's your last day on earth
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Re: Rocker to valve tip contact - your opinion?
[Re: Diplomat360]
#2105378
07/07/16 12:02 AM
07/07/16 12:02 AM
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Joined: Jun 2005
Posts: 6,257 gulfport, ms, west mi
rowin4
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master
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gulfport, ms, west mi
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Just one thing to keep in mind when you shim the rocker shaft. The rocker stands that are cast into the heads are machined for the size of the shaft. when you put that .40 shim in there it increases the shaft diameter to a larger size and puts stress on the outer tops of the rocker stands. This sometimes splits the stands giving shim the room it needs and also scraping the head.
it's ok to butt heads, just don't do it with a butthead
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Re: Rocker to valve tip contact - your opinion?
[Re: rowin4]
#2105399
07/07/16 12:31 AM
07/07/16 12:31 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Just one thing to keep in mind when you shim the rocker shaft. The rocker stands that are cast into the heads are machined for the size of the shaft. when you put that .40 shim in there it increases the shaft diameter to a larger size and puts stress on the outer tops of the rocker stands. This sometimes splits the stands giving shim the room it needs and also scraping the head. There are shims made that tapper to zero on the sides
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Re: Rocker to valve tip contact - your opinion?
[Re: Diplomat360]
#2105595
07/07/16 11:08 AM
07/07/16 11:08 AM
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Joined: Oct 2007
Posts: 4,219 New York
polyspheric
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master
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New York
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literally perfect, dead smack in the middle of the valve-tip
It's of relatively little importance. How wide the contact is, and when it changes direction are far more important.
Boffin Emeritus
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Re: Rocker to valve tip contact - your opinion?
[Re: Diplomat360]
#2105923
07/07/16 09:12 PM
07/07/16 09:12 PM
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Joined: Sep 2014
Posts: 4,457 Washington
madscientist
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Do yourself a favor and call B3 racing engines. Go to his web site and look at his tech pages. There is much more to geometry than roller position.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: Rocker to valve tip contact - your opinion?
[Re: madscientist]
#2105962
07/07/16 10:31 PM
07/07/16 10:31 PM
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Joined: Jul 2013
Posts: 561 USA
B3RE
mopar
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mopar
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Do yourself a favor and call B3 racing engines. Go to his web site and look at his tech pages. There is much more to geometry than roller position. That's my opinion, too.
Mike Beachel
I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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Re: Rocker to valve tip contact - your opinion?
[Re: MadMopars]
#2106023
07/08/16 12:03 AM
07/08/16 12:03 AM
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Joined: Jul 2013
Posts: 561 USA
B3RE
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mopar
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On another note, there is way more to valve train geometry than just where the rocker tip is sitting in relation to the valve tip in one given position. If you want to be educated on it and lose alot of sleep while pondering all the variables, call Mike at B3 Racing. He's a wealth of knowledge. FWIW, I don't recommend roller rockers if you don't absolutely need to use them. Trent, You're not still losing sleep over rocker geometry I hope. Not to get off topic, but I hope the family is well, and I'll bet that baby girl is growing like a weed. Ok, back to the topic.
Mike Beachel
I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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Re: Rocker to valve tip contact - your opinion?
[Re: Diplomat360]
#2106160
07/08/16 10:23 AM
07/08/16 10:23 AM
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Joined: Jan 2003
Posts: 1,797 Windsor, ON, Canada
Diplomat360
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Guys! Thanks for all the responses. Yes, the geometry question is a fairly complex issue. Of all the articles, books, materials I have read on this subject my favourite one has got to be the one I've attached to this post. I also agree that simplyfing it by only looking at the rocker arm to valve tip alignmnet is merely addressing part of the issue. However...for my build I am really not going to change much else...so if the center of the shaft is off in relation to the valve stem tip (horizontally speaking) and the full sweep of the rocker arm nose does not make a perfect arc. with a great 90 deg. at half-lift...well, so be it, because correcting this would require more extensive work/re-work that is simply not in my budget for these parts. What I can control however is the alignment, and it's really by means of either using the shims (Hughes Engines) or the valve stem cap. I have never ran caps in the past, but for a non-roller rocker they do certainly increase the area where the sweep contact is made, which means the pressure is distributed better and the valve tip itself does not take the "beating" otherwise. The opposite is true (even more so due to the materials) for the rocker arm itself... Great ideas, I will probably pull the springs on 1 cylinder and try to do the full-sweep pattern check with just a checking spring. I had actually done this a few months back before I pulled the heads, this is what the pattern looked like with no use of the shims or caps: The sweep mark was too far to the rocker nose-tip for my liking, so by elevating the rocker (shaft shims) I was driving towards a more centered mark on the rocker nose. The valve stem tips on the other hand were a little too far towards exhaust, which seemed to have matched what I was seeing on the rocker nose itself.
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Re: Rocker to valve tip contact - your opinion?
[Re: Diplomat360]
#2106176
07/08/16 11:04 AM
07/08/16 11:04 AM
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Joined: Nov 2011
Posts: 2,154 Its a TRAP!
DARTH V8Я
Oh No!! I just had a moron attack!
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Oh No!! I just had a moron attack!
Joined: Nov 2011
Posts: 2,154
Its a TRAP!
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I'd wouldn't use checker springs imo.. check with the springs you'll be using. Also, it doesn't really matter if the rocker pad/roller is centered on the valve. Short sweep is what yah want, & the edge of the roller or pad do not go over the edge of the valve stem.
When it takes more than a sweet mullet to prove you rule at the trailer park..
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Re: Rocker to valve tip contact - your opinion?
[Re: Diplomat360]
#2106501
07/08/16 08:09 PM
07/08/16 08:09 PM
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Joined: Nov 2011
Posts: 2,154 Its a TRAP!
DARTH V8Я
Oh No!! I just had a moron attack!
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Oh No!! I just had a moron attack!
Joined: Nov 2011
Posts: 2,154
Its a TRAP!
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Also, wouldn't longer P-rods help shorten the sweep?
When it takes more than a sweet mullet to prove you rule at the trailer park..
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Re: Rocker to valve tip contact - your opinion?
[Re: polyspheric]
#2106585
07/08/16 11:00 PM
07/08/16 11:00 PM
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Joined: Feb 2003
Posts: 12,675 Columbia, CT
moper
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How wide the contact is, and when it changes direction are far more important.
x2. It would not be acceptible to me. What was done to the heads?
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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