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Re: Broken rocker shafts
[Re: Jeepmon]
#1088055
10/03/11 11:08 PM
10/03/11 11:08 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Whats the open spring pressure and were the hold down bolts tight and not over tightened to distort the shafts 
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Re: Broken rocker shafts
[Re: Jeepmon]
#1088057
10/03/11 11:51 PM
10/03/11 11:51 PM
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Joined: Feb 2004
Posts: 1,093
Long Beach, CA
Mike Swann
super stock
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super stock
Joined: Feb 2004
Posts: 1,093
Long Beach, CA
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Interesting, I have bent them pretty bad, but never broke any.
8.30's @3400 lbs
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Re: Broken rocker shafts
[Re: sixpackgut]
#1088059
10/04/11 12:06 AM
10/04/11 12:06 AM
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Joined: Aug 2008
Posts: 4,072
Mo.
racerx
master
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master
Joined: Aug 2008
Posts: 4,072
Mo.
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Quote:
what kind of times does a B! headed 451 run? 
^^^^^what he said^^^^ 
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Re: Broken rocker shafts
[Re: Jeepmon]
#1088060
10/04/11 12:25 AM
10/04/11 12:25 AM
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Joined: Aug 2003
Posts: 43,252
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,252
Bend,OR USA
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Quote:
I'm not sure what the open pressure of the springs are.. that is something I need to check... but I'm fairly certain its not too extreme as its only a 650 lift roller cam..
The last time we had the shafts off the motor, we torqued them back down using the stock spec, so I doubt that was the problem.. and IIRC.. isnt it something like 25 or 30 lbs?
The factory service manuals call for 23 to 25 Ft lbs on the stock shafts  T%D calls for 35 Ft lbs on there single shaft rockers, so does Harland Sharp, I think. Call Koffels 419-433-4410 to get the correct specs on there heads and rockers. BTW I have a brand new complete set of oringinal 3 year old B1 rockers, shafts and holdowns that I am not going to use, PM me if interested in them cheap   I bought a set of new TD rockers, shafts and holdodwns from another member on here so no need for these
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Broken rocker shafts
[Re: Cab_Burge]
#1088061
10/04/11 12:41 AM
10/04/11 12:41 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Quote:
I'm not sure what the open pressure of the springs are.. that is something I need to check... but I'm fairly certain its not too extreme as its only a 650 lift roller cam..
The last time we had the shafts off the motor, we torqued them back down using the stock spec, so I doubt that was the problem.. and IIRC.. isnt it something like 25 or 30 lbs?
The factory service manuals call for 23 to 25 Ft lbs on the stock shafts T%D calls for 35 Ft lbs on there single shaft rockers, so does Harland Sharp, I think. Call Koffels 419-433-4410 to get the correct specs on there heads and rockers. BTW I have a brand new complete set of oringinal 3 year old B1 rockers, shafts and holdowns that I am not going to use, PM me if interested in them cheap I bought a set of new TD rockers, shafts and holdodwns from another member on here so no need for these
The stock bolts were 5/16 and he will have 3/8
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Re: Broken rocker shafts
[Re: Jeepmon]
#1088064
10/04/11 11:06 AM
10/04/11 11:06 AM
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Joined: Nov 2004
Posts: 3,544
Syracuse,NY
CompWedgeEngines
master
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master
Joined: Nov 2004
Posts: 3,544
Syracuse,NY
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1) Are they original B1 supplied shafts? 2) How old are they? ( how many passes?) 3) If your sure they were/are torqued properly, and not over OR undertightened, then I'd simply say fatigue. 4) Rocker shafts are a kind of odd animal. They technically need to have two different heat treats on the shafts. The arears around the bolt holes actually need to be tretated differently than the rest of the shaft. This can have a major effect on how well they survive. There are obviously some better shafts out there as well, such as T&D, Harland Sharp and some private manufacters. My guess is the shafts finally gave up, unless you know something about them we dont...?... 
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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Re: Broken rocker shafts
[Re: Bob_Coomer]
#1088068
10/04/11 05:16 PM
10/04/11 05:16 PM
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Joined: Jun 2005
Posts: 793
Utah
topbrent
super stock
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super stock
Joined: Jun 2005
Posts: 793
Utah
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Quote:
Was shims used under the shafts? just wondering...
Any pearls of wisdom to share on shims?
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Re: Broken rocker shafts
[Re: topbrent]
#1088069
10/04/11 08:10 PM
10/04/11 08:10 PM
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Joined: Mar 2008
Posts: 1,596
BX, CT, FL.
B1KILLER
pro stock
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pro stock
Joined: Mar 2008
Posts: 1,596
BX, CT, FL.
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Use to break them all the time till I went to T.D., Then I started to pull the shaft bolts clean off the head on my 499, it ran good, when it would stay together... 
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The torque specs on the LA rocker shaft bolts where not much less than the B/RB shafts 
I have seen it many times it is nothing unusual, nor is it unusual for folks to have broken shafts and not realize it. Just saying 
