Re: Valve Train Deflection
[Re: sg66mopar]
#901532
01/10/11 09:20 PM
01/10/11 09:20 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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There are only 2 places that have a lot of compliance, and only 1 that's easy to fix. How big are your pushrods?
Boffin Emeritus
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Re: Valve Train Deflection
[Re: sg66mopar]
#901537
01/10/11 11:19 PM
01/10/11 11:19 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Is this a single shaft system... you most likely have a few different places flexing.... the push rod, the rockers and the shafts EDIT Forgot to add the cam itself flexing but your not running big spring pressure... whats the cam diameter
Last edited by MR_P_BODY; 01/11/11 12:20 AM.
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Re: Valve Train Deflection
[Re: MR_P_BODY]
#901538
01/11/11 12:10 AM
01/11/11 12:10 AM
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Joined: Dec 2008
Posts: 1,200 UK
602heavy
pro stock
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pro stock
Joined: Dec 2008
Posts: 1,200
UK
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Are both heads on & valve train lashed?
Last edited by 602heavy; 01/11/11 12:12 AM.
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Re: Valve Train Deflection
[Re: MR_P_BODY]
#901540
01/11/11 02:15 AM
01/11/11 02:15 AM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
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master
Joined: Oct 2007
Posts: 4,209
New York
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I agree the shafts probably move, but it can't be much or something would give up. 7/16" is going to help a lot more than it sounds, it's worth doing if only to remove (or at least minimize) 1 variable. Taper is just as strong as single diameter, since the "bendy" part is mid-point (the ends could be 1/4" for the last inch without penalty).
Boffin Emeritus
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Re: Valve Train Deflection
[Re: sg66mopar]
#901541
01/11/11 02:25 AM
01/11/11 02:25 AM
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Joined: Jan 2003
Posts: 19,377 Las Vegas
Al_Alguire
I Live Here
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I Live Here
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Posts: 19,377
Las Vegas
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FWIW I run Manton Pushrods. They are 7/16"x.168" wall. I have about .020" deflection in mine. Lobe lift is basically the same. I also run a lot more spring. Mine are 1010 open. Also I run T&D paired rocker gear.
On my last B1 original motor I ran a 3/8" Smith Brothers pushrod with a little less lobe lift than you and say about .040"+-. I also ran the manley 850lb springs. This was with T&D common shaft rockers. Could have been the sommon shaft or maybe it was the pushrod??
Had to go check over my notes but that is what I found.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Valve Train Deflection
[Re: polyspheric]
#901542
01/11/11 01:34 PM
01/11/11 01:34 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
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master
Joined: Oct 2007
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New York
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The single shafts are a PITA to upgrade. IIRC OD is 7/8"? The OD is far the biggest factor, but needs everything changed (stands, rockers). Comparo, with 7/8" OD with 1/8" wall as 100%: 1" OD with 1/8" wall = +57.7%
The material doesn't matter at all - moly isn't less bendy than mild steel and alum is worthless. Wall thickness is what's left, and it doesn't do much (although it's cheap and there's no down-side). You don't even really need it hardened or chromed if you have bushings (needle bearings or plain rocker ID: absolutely necessary).
Comparo, with 7/8" OD with 1/8" wall as 100%: 7/8" OD with 1/4" wall = +30.6% 7/8" OD with 3/8" wall = +35.1% Give me your wall thcikness and I'll do the math for you.
Another stand between the existing might do something, but not much room. Upsizing all the stand hardware will improve location (i.e., 5/16" > 3/8", etc.) but the heads have to be tapped, not much room in the stuff, etc. Extending all stand/cap hardware upward and using a fabricated tie-bar will do something, but the obvious problems: 1. must clear the rocker path, so tall 2. no clearance in the cover 3. must be reamed to accept stand studs
Boffin Emeritus
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Re: Valve Train Deflection
[Re: Al_Alguire]
#901543
01/11/11 02:01 PM
01/11/11 02:01 PM
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Joined: Apr 2005
Posts: 1,106 Quebec, Canada
Diablo
super stock
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super stock
Joined: Apr 2005
Posts: 1,106
Quebec, Canada
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Quote:
FWIW I run Manton Pushrods. They are 7/16"x.168" wall. I have about .020" deflection in mine. Lobe lift is basically the same. I also run a lot more spring. Mine are 1010 open. Also I run T&D paired rocker gear.
What series Manton are they?
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Re: Valve Train Deflection
[Re: polyspheric]
#901545
01/11/11 02:54 PM
01/11/11 02:54 PM
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Joined: Nov 2003
Posts: 1,664 North Sweden
RT540
top fuel
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top fuel
Joined: Nov 2003
Posts: 1,664
North Sweden
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Quote:
The material doesn't matter at all - moly isn't less bendy than mild steel and alum is worthless. Wall thickness is what's left, and it doesn't do much (although it's cheap and there's no down-side). You don't even really need it hardened or chromed if you have bushings (needle bearings or plain rocker ID: absolutely necessary).
Modulus of elasticity for steel is around 29, (10x6 psi) You are right, alum will bend easy 10, (10x6 psi) titanium is a little better with 15.5 A common misunderstanding, is that a molly chassi is stiffer than a mild steel, but the modulus is about the same and with thinner walls, the molly tubes will flex( bend more then the same diameter mild steel). Stretch as in permanent deformation, is what cr-mo is good for.
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Re: Valve Train Deflection
[Re: JD Dart]
#901547
01/11/11 08:24 PM
01/11/11 08:24 PM
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Joined: Oct 2009
Posts: 1,288 Oregon
sg66mopar
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Oregon
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Quote:
Aren’t you running the Koffles rockers arms and shafts? If so you will need spares I have a full set with spares. Looks like you will need better pushrods. I’m running .145 wall 3/8 pushrods the 7/16 would be better.
Are you looking to part with some or am I reading between the lines.
New ones are $480. At that point I'd probably step up to T&Ds.
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Re: Valve Train Deflection
[Re: sg66mopar]
#901548
01/12/11 04:39 AM
01/12/11 04:39 AM
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Joined: May 2006
Posts: 740 WA
JD Dart
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super stock
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Sure I'll give you a stealing deal on my stuff it includes pushrods too. Went with T&D. Email me jkcomp5957@yahoo.com
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