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SB cam lift/dur, how much net is lost by 59 degree? #1346326
12/05/12 09:57 AM
12/05/12 09:57 AM
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Weddington, N.C.
Streetwize Offline OP
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I could probably Trig this out but I figured AndyF or Polyspheric already figured it out.

Everybody knows the 59 degree LA lifter bank was a cost saving carry-over from the 318 Poly. My question is, has anybody figured out the lift/duration effects of the offset lifter angle?

Every time I do a sb (especially a roller) I'm amazed how much the pushrod arc has to oscillate compared to other motors.

I also know the arc gets worse the further the base of the lifter cup is from the cam centerline.

Last edited by Streetwize; 12/05/12 10:10 AM.

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Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: Streetwize] #1346327
12/05/12 10:27 AM
12/05/12 10:27 AM
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one bad fish Offline
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Would like to here the answer on this one interesting

Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: one bad fish] #1346328
12/05/12 10:39 AM
12/05/12 10:39 AM
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Weddington, N.C.
Streetwize Offline OP
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What got me thinking about it is there is some interesting cause and effct info regarding pushrod deflection and arc motion on the Manton website. The "bad" example made me say "Hey! That looks like a small block MoPar!"


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: one bad fish] #1346329
12/05/12 10:46 AM
12/05/12 10:46 AM
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oberlin, Ohio
Rapid340 Offline
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If you place a dial indicator at 45 degrees at the end of a long pushrod, you will loose close to three percent. The loss will increase with shorter pushrods and increase thru the lift cycle.

But how it affects actual valve lift is much more complex and will depend on the rocker stud angular position, rocker dimentions, lifter and pushrod length as well as the rocker tip design. I suspect the designers added the lifter angle offset to allow the pushrod to move with the rocker stud relative to the rocker shaft (pivot) centerline on the original design but that is just a guess. If someone knows firsthand, please let me/us know.



Last edited by Rapid340; 12/05/12 11:29 AM.

1971 Factory Appearing Duster 340 11.000 @ 122 mph
Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: Rapid340] #1346330
12/05/12 11:03 AM
12/05/12 11:03 AM
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Weddington, N.C.
Streetwize Offline OP
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I think pushrod geometry and dynamics is a LOT more complex than many people realize, mainly because each end of the rod is moving in a seperate arc. the closer to the cam centerline the lifter cup is lengthens the rod but reduces the severity of the arc.


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: Streetwize] #1346331
12/05/12 11:31 AM
12/05/12 11:31 AM
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On the south side of Nowhere
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S/ST 3040 Offline
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Roughly .012" @ valve, with a 1.5 rocker..........IIRC.

Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: S/ST 3040] #1346332
12/05/12 02:56 PM
12/05/12 02:56 PM
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Streetwize Offline OP
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Vic,

Thought you might show up

Thanks, buddy!

I knew a builder who angle clearanced the pushrod passages in Aluminum heads so that they'll just slightly "kiss" the pushrod at the base of the deck surface (at HIGH RPM or Peak of pushrod deflection) ; He claimed it acted a as a guideplate by limiting the side to side motion and dampened the harmonics in the pushrod. claimed the valvetrain stayed more stable at High RPM and the 'friction' was minimal. Never gave it much thought but on a small block mopar I can sort of see the logic in it.

Last edited by Streetwize; 12/05/12 03:14 PM.

WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: Streetwize] #1346333
12/05/12 06:56 PM
12/05/12 06:56 PM
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emarine01 Offline
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I use .050 on the 59* offset mopar intake W2/W5 stuff

Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: S/ST 3040] #1346334
12/05/12 06:57 PM
12/05/12 06:57 PM
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fredericksburg,va
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cudaman1969 Offline
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Quote:

Roughly .012" @ valve, with a 1.5 rocker..........IIRC.



Roughly same thing I got with the 360-380 crate motor cam. First time I worked with a small block, very bad push rod angle. This was the first thing Glidden fixed in the pro stock 79 Arrow, he was unbeatable.

Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: Streetwize] #1346335
12/05/12 07:01 PM
12/05/12 07:01 PM
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sweden
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1Fast340 Offline
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Quote:

Vic,

Thought you might show up

Thanks, buddy!

I knew a builder who angle clearanced the pushrod passages in Aluminum heads so that they'll just slightly "kiss" the pushrod at the base of the deck surface (at HIGH RPM or Peak of pushrod deflection) ; He claimed it acted a as a guideplate by limiting the side to side motion and dampened the harmonics in the pushrod. claimed the valvetrain stayed more stable at High RPM and the 'friction' was minimal. Never gave it much thought but on a small block mopar I can sort of see the logic in it.




im not sure i like his way of thinking,my moly pushrods slightly touch the heads in a very few spots and they have lost some material there. at first i would have suspected that the aluminum heads should have been eaten first but this does not seem to be the case, however i have never measured the wear on the pushrods but its defenitly there by just fingertip precision measuring device metod. also keep in mind that these pushrods have been beaten on with a variety of solidroller cams since noone knows how long and might have started flexing more than they should,and the wear started after the instalation of aluminum heads in 2005 i would gues.

Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: 1Fast340] #1346336
12/05/12 07:36 PM
12/05/12 07:36 PM
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Weddington, N.C.
Streetwize Offline OP
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1 fast, I see what your saying and I thought the same thing...but he countered by saying the effective contact area (small diameter pushrod inside of a larger tunnel in the head) leaves very little of an actual 'wear patch' at any given cycle and the benefits of keeping the pushrod from going all "harmonic" (ocillating not only 'fore and aft' with the normal lifter to rocker action) but also laterally...so the guideplate analogy meant a more 'solid' transfer of energy to the rocker. asuming the pushrod is rotating as it 'wears' a uniform wear pattern (shiny like a slight polishing or galling I suppose) was proof (to him) that it was working and the push rod was spinning on its axis so therefore "not bent". So long as nothing was binding he saw no harm in it. His point was that short of repositioning the lifter bores (a la Glidden) the negatives of the bad harmonics was worse at high RPM than the slight wear and friction it took to dampen it, this was from a guy that had a LOT of winston cup years under his belt. Again....

The first time I pulled the intake off a Small block mopar and saw the lifters I thought it looked more like a VW "pancake" motor than a V8

Last edited by Streetwize; 12/05/12 07:55 PM.

WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: Streetwize] #1346337
12/05/12 08:19 PM
12/05/12 08:19 PM
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Finland
mafo Offline
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It gets worse with more rocker offset , on my w2 engine it was bad, 1 inch offset rockers...
we put one dial indicator on the lifter and an other on the valve, and it was
to bad I never wrote it down, but my theoretical .750 lift was more like .700


-65 Valiant,420", all motor,2700#, dot tires, 8,42 @ 160,2
Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: mafo] #1346338
12/05/12 11:37 PM
12/05/12 11:37 PM
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fredericksburg,va
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cudaman1969 Offline
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Push rods don't turn with roller cam I thought? Or are we talking solids?

Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: cudaman1969] #1346339
12/06/12 10:21 AM
12/06/12 10:21 AM
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Weddington, N.C.
Streetwize Offline OP
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I would think any ball cup pushrod with lash would try to rotate, it certainly oscillates and incurs harmonics, no?


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: SB cam lift/dur, how much net is lost by 59 degree? [Re: Streetwize] #1346340
12/06/12 12:03 PM
12/06/12 12:03 PM
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CompWedgeEngines Offline
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Quote:

Vic,

Thought you might show up

Thanks, buddy!

I knew a builder who angle clearanced the pushrod passages in Aluminum heads so that they'll just slightly "kiss" the pushrod at the base of the deck surface (at HIGH RPM or Peak of pushrod deflection) ; He claimed it acted a as a guideplate by limiting the side to side motion and dampened the harmonics in the pushrod. claimed the valvetrain stayed more stable at High RPM and the 'friction' was minimal. Never gave it much thought but on a small block mopar I can sort of see the logic in it.





This man was a smart man.

When you get into blown alky stuff, you learn a lot about pushrods, as well as when you talk to Pro Stock and ADRL guys....you'd be amazed.


RIP Monte Smith

Your work is a reflection of yourself, autograph it with quality.

WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.






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