Aluminum Rocker Arm Material Specification?
#1454462
06/17/13 03:07 PM
06/17/13 03:07 PM
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Joined: Jan 2003
Posts: 5,444
Indiana
YO7_A66
OP
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OP
master
Joined: Jan 2003
Posts: 5,444
Indiana
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What series aluminum do the major rocker arm manufacturers use on the Mopar rocker arms?
I read that Dove specifies "7000" series aluminum (on their web sight) for their rockers.
EDIT:
* Harland Sharp / Hughes = 2024-T3511 extrusions (REF: tensile = 68ksi, yield = 41ksi)
* Dove = 7000 (REF: tensile = 58ksi, yield = 52ksi)
The HS/Hughes and the Dove average out (T/Y)to be right at the same ratings.
What material are the others using that you know of? (Comp, Crane, HS, etc.)
What series of aluminum do I stay away from when purchasing?
This coming Fall I will be in the market to buy a set of the aluminum rockers and I am just doing my homework.
Thanks
Last edited by YO7_A66; 06/18/13 09:05 AM.
1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
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Re: Aluminum Rocker Arm Material Specification?
[Re: YO7_A66]
#1454465
06/18/13 01:54 PM
06/18/13 01:54 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
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Yes, I have that issue at home. As a mechanical designer, I have to say a few things: 1. Everything depends on the design. The designer makes the design, figures out the material needs, and specifies a material that meets the needs. Better designers make better design choices. 2. As someone is likely to point out, EVERY aluminum alloy has a fatigue life and at SOME number of cycles, the strength will fall below the requirement of the part and it will fail. Now, there is still a lot of discussion about what constitutes a cycle. Facts are, aluminum pistons seem to last indefinitely. Aluminum rocker arms (the good ones) rarely fail, and when they do, it's usually a failure precipitated by another cause than fatigue. 3. It is possible to use a really good material and with a bad design, have failures. 4. It is possible to have a good design and good material, but because of bad manufacturing processes, have failures. 5. It is possible to have good design, material, AND manufacturing processes and have the failure because of a wrong application. Conclusion: While, on the surface, material seems to play a big role, the sum total of design, material, manufacturing process and application determines whether the part will work and survive, or not. R. 
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Re: Aluminum Rocker Arm Material Specification?
[Re: YO7_A66]
#1454466
06/18/13 03:42 PM
06/18/13 03:42 PM
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Joined: Nov 2004
Posts: 1,708
S. Il. U.S.A.
5spdcuda
top fuel
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top fuel
Joined: Nov 2004
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S. Il. U.S.A.
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Dogdays points are well taken. As to your specific question regarding material, I had an interesting [ to me anyway ] conversation this morning with a representative of Dove manufacturing. He was unable to confirm outright that Indy rockers are made by Dove but he did say that he was very familiar with Indy's rockers and that they were definitely made of 7100 series aluminum alloy. I am not a metallurgist, but I do know that the primary alloying element in 7000 series is zinc and that it has the highest tensil stength of all aluminum alloys [ in excess of 70,000 psi when heat treated ] and is used extensively in the aircraft industry for structrual components. It is also used by Smith & Wesson for aluminum framed handguns. 2024 As used by Harlan Sharp is also a very strong alloy [ copper being the primary alloying element ] and is also used by the aircraft industry. In short keeping in mind Dog's admonition regarding design, heat treated 7000 series is as good a material as we are likely to find in an aluminum rocker.
Last edited by 5spdcuda; 06/18/13 03:55 PM.
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Re: Aluminum Rocker Arm Material Specification?
[Re: YO7_A66]
#1454467
06/18/13 05:45 PM
06/18/13 05:45 PM
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Joined: Jan 2003
Posts: 75,047
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,047
U.S.S.A.
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Quote:
What series aluminum do the major rocker arm manufacturers use on the Mopar rocker arms?
I read that Dove specifies "7000" series aluminum (on their web sight) for their rockers.
EDIT:
* Harland Sharp / Hughes = 2024-T3511 extrusions (REF: tensile = 68ksi, yield = 41ksi)
* Dove = 7000 (REF: tensile = 58ksi, yield = 52ksi)
The HS/Hughes and the Dove average out (T/Y)to be right at the same ratings.
What material are the others using that you know of? (Comp, Crane, HS, etc.)
What series of aluminum do I stay away from when purchasing?
This coming Fall I will be in the market to buy a set of the aluminum rockers and I am just doing my homework.
Thanks
I would stay away from alum all together, if you must buy an alum rocker make sure it has these 2 properties ..
It is has a bronze bushing where it rides on the shaft
AND
Itt's not an offshore piece of crap .
I'd buy Comp pro magnums ...
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Re: Aluminum Rocker Arm Material Specification?
[Re: JohnRR]
#1454469
06/26/13 02:38 AM
06/26/13 02:38 AM
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Joined: Feb 2004
Posts: 4,501
Gainesville,FL
goldmember
master
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master
Joined: Feb 2004
Posts: 4,501
Gainesville,FL
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Quote:
Quote:
What series aluminum do the major rocker arm manufacturers use on the Mopar rocker arms?
I read that Dove specifies "7000" series aluminum (on their web sight) for their rockers.
EDIT:
* Harland Sharp / Hughes = 2024-T3511 extrusions (REF: tensile = 68ksi, yield = 41ksi)
* Dove = 7000 (REF: tensile = 58ksi, yield = 52ksi)
The HS/Hughes and the Dove average out (T/Y)to be right at the same ratings.
What material are the others using that you know of? (Comp, Crane, HS, etc.)
What series of aluminum do I stay away from when purchasing?
This coming Fall I will be in the market to buy a set of the aluminum rockers and I am just doing my homework.
Thanks
I would stay away from alum all together, if you must buy an alum rocker make sure it has these 2 properties ..
It is has a bronze bushing where it rides on the shaft
AND
Itt's not an offshore piece of crap .
I'd buy Comp pro magnums ...
I kinda agree. For the mild combo you list the only benefit is weight loss( a few ounces?Not likely)) and nothing more,no slight rocker ratio change will net a hp increase that is measurable. Lot's of $$$$ spent to likely have less reliability in the long run for such a mild street build. I do agree that if you must put any aftermarket rocker on it don't waste time with any cheap units.
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Re: Aluminum Rocker Arm Material Specification?
[Re: goldmember]
#1454470
06/26/13 08:33 AM
06/26/13 08:33 AM
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Joined: Jan 2003
Posts: 5,444
Indiana
YO7_A66
OP
master
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OP
master
Joined: Jan 2003
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Indiana
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I want a steel roller rocker arm, but I am having trouble finding one with a 1.6 ratio. I think that I found a set from Crane, but the price seemed to be too good to be true. So I have been looking at the aluminum kits.
I am mainly looking to upgrade now in the case that I have engine work done in the future. If I can budget the rocker arms now, then that would already be taken care of down the road if I have any head work done.
Does anyone know of a "good" steel set (kit) of 1.6's for a sb? Comp only had the 1.5's that I could find.
Thanks
1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
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Re: Aluminum Rocker Arm Material Specification?
[Re: 5spdcuda]
#1454471
06/26/13 10:07 AM
06/26/13 10:07 AM
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Joined: Dec 2003
Posts: 22,696
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,696
Bitopia
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Quote:
Dogdays points are well taken. As to your specific question regarding material, I had an interesting [ to me anyway ] conversation this morning with a representative of Dove manufacturing. He was unable to confirm outright that Indy rockers are made by Dove but he did say that he was very familiar with Indy's rockers and that they were definitely made of 7100 series aluminum alloy. I am not a metallurgist, but I do know that the primary alloying element in 7000 series is zinc and that it has the highest tensil stength of all aluminum alloys [ in excess of 70,000 psi when heat treated ] and is used extensively in the aircraft industry for structrual components. It is also used by Smith & Wesson for aluminum framed handguns. 2024 As used by Harlan Sharp is also a very strong alloy [ copper being the primary alloying element ] and is also used by the aircraft industry. In short keeping in mind Dog's admonition regarding design, heat treated 7000 series is as good a material as we are likely to find in an aluminum rocker.
However one factor left out of this discussion is operating temp, and we all know that around 400F, alum has lost a lot of strength, but each alloy has a different heat curve, and that is tougher to decipher for each application. For any street/endurance application, alum rockers offer few advantages compared to the tradeoffs, IMO
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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