Kid Vette
Master-Baiter
Tool & Die/Mold Maker and Designer
Calling Jim Shea
- Thread starter big2bird
- Start date
turtlevette
The Turdle
Glue the bearing sleeves in with locktite. As you say i doubt there enough expansion to loosen it up that much. Low load slow rotating application is not going to be a problem anyway even if the races slip a little.
I wouldn't have any qualms about duplicating that housing exactly (not thicker) in AL if it's going to drive power steering. The loads will not be high at all. A forged billet block of high strength AL might be just as strong as pig iron.
Lots of worry warts around. Jim has to think differently. When you're a professional engineer at a big manufacturer you have to be liability adverse out of necessity.
For hotrodders application it's just fine, but to reiterate my post above lots of effort and $$$$$ for just a few pounds. Theres got to be other more cost effective things that can save weight before doing this. There is a lot of unnecessary metal forward of the radiator. You'd probably save more weight replacing the front sway bar with a tube.
mrvette
Phantom of the Opera
NOT that I really care all that much, but just what weight savings, if any, was there for the rack conversion....using the steeriods or VBP rack conversion....my bet it amounts to a even swap on their stuff....
but no guess for mine....;-)))
:harhar:
redvetracr
Well-known member
[/QUOTE]
Once I hear this kind of thing, the entire credibility of the company goes south.[/QUOTE]
the creditibility of that company went south years ago when they were known as fast corvette dot com.....
Once I hear this kind of thing, the entire credibility of the company goes south.[/QUOTE]
the creditibility of that company went south years ago when they were known as fast corvette dot com.....
69427
The Artist formerly known as Turbo84
I have to think there's a net weight loss with the rack conversion. I would guess that there's a fairly equal weight between the stock p/s cylinder/ram, control valve, and the steering arms, and the weight of the GA rack. But I would think the extra linkage and u-joints needed for the conversion would be lighter than the original steering box.
mrvette
Phantom of the Opera
It's a shame I didn't think to weigh those parts out years ago...I just remember the heft of them when taking out and thinking that rack was SO much lighter, the input linkage being almost nothing to add...maybe 5 lbs at most....I remember that rack was much less then the idler arm, link, and so forth....the added weight of the power piston and end mount was all additional, just by recollection....like I said...
but that is with MY mounting brackets, not the commercial mounts....
The August 2002 issue of Vette magazine covered a Steeroids installation into their '72 Stingray. They indicated a 12 lb savings over the production power steering system. I assume that they weighed everything (i.e. flex coupling versus universal joints; cast iron gear, assist cylinder, and linkage versus rack & pinion gear with tie rods; etc) so that the 12 lb figure was "apples to apples."
Jim
Jim
Corvettes White
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So I did a little thinking last night based on the comments you all have made.
Gray Iron v Malleable Iron v Aluminumn.
Gray Iron ASTM A 48
E = 24,000,000 psi
Fy = none (too brittle.)
Fu = 50,000 psi.
Snf = 20,000 psi.
Malleable Iron ASTM A 47
E = 24,000,000 psi
Fy = 33,000 psi. (this is the governing number for most designs of thigs.)
Fu = 70,000 psi.
Snf = 28,000 psi.
Aluminumn ASTM A 6061
E = 10,000,000 psi
Fy = 35,000 psi per spec, 40,000 psi typically.
Fu = 42,000 psi per spec, 45,000 psi typically.
Snf = 19,000 psi.
And looking in the Chevrolet overhaul manual, All the bearings are in races, not running on the casting.
So, an aluminum case for the same thickness is as strong as a gray iron case based on yield; but it does take more to crush the iron case.
The aluminum case is going to deflect twice as much as the iron case. To compensate the aluminum case would need to be half as much again thicker.
Unless the wall thickness of the case were driven more by casting limitations and less by strength or stiffness requirements.
So for fatigue, aluminum is almost up there with the gray iron. I am aware of the ears snapping off, any other failure problems with the case?
For a one off, I am thinking that it might be best to fabricate from bent plate and tube as opposed to billet machining. Filler rod 4043 or 5356.
I do not see where I am blowing smoke. Guys?
Gray Iron v Malleable Iron v Aluminumn.
Gray Iron ASTM A 48
E = 24,000,000 psi
Fy = none (too brittle.)
Fu = 50,000 psi.
Snf = 20,000 psi.
Malleable Iron ASTM A 47
E = 24,000,000 psi
Fy = 33,000 psi. (this is the governing number for most designs of thigs.)
Fu = 70,000 psi.
Snf = 28,000 psi.
Aluminumn ASTM A 6061
E = 10,000,000 psi
Fy = 35,000 psi per spec, 40,000 psi typically.
Fu = 42,000 psi per spec, 45,000 psi typically.
Snf = 19,000 psi.
And looking in the Chevrolet overhaul manual, All the bearings are in races, not running on the casting.
So, an aluminum case for the same thickness is as strong as a gray iron case based on yield; but it does take more to crush the iron case.
The aluminum case is going to deflect twice as much as the iron case. To compensate the aluminum case would need to be half as much again thicker.
Unless the wall thickness of the case were driven more by casting limitations and less by strength or stiffness requirements.
So for fatigue, aluminum is almost up there with the gray iron. I am aware of the ears snapping off, any other failure problems with the case?
For a one off, I am thinking that it might be best to fabricate from bent plate and tube as opposed to billet machining. Filler rod 4043 or 5356.
I do not see where I am blowing smoke. Guys?
big2bird
Charter Member, Founder Bird-Run, Cruise-In Bird-R
Hmm. No engineer here, but what about a stock copy cat casting with integral 1/4" ribs going to the mounting ears. cast two, and have one tested . I know a guy..........
Corvettes White
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So I looked up some casting alu. and the one below showed up. That is better thatn a lot of steels out there.
Aluminumn ANSI 201.2 T-6 or T-7
E = 10,300,000 psi
Fy = 50,000 psi.
Fu = 60,000 psi.
Snf = NA.
Can we doo this stuff? shrinkage about 4 - 8%.
George
Aluminumn ANSI 201.2 T-6 or T-7
E = 10,300,000 psi
Fy = 50,000 psi.
Fu = 60,000 psi.
Snf = NA.
Can we doo this stuff? shrinkage about 4 - 8%.
George
Corvettes White
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Those three steering gears are all manual. There were a couple aluminum manual steering gears manufactured at Saginaw. (Corvair and Vega- both light weight small cars.) We always cringed when we say 180 mph dragsters using the aluminum Corvair box back in the old days.
We never manufactured an aluminum power gear. I am quite sure that the pressures and loading of the rack piston against aluminum would have worn out an aluminum housing. Note, that Saginaw laser hardened the housing bore on the cast iron 700 and 800 power gears for best durability.
Jim
We never manufactured an aluminum power gear. I am quite sure that the pressures and loading of the rack piston against aluminum would have worn out an aluminum housing. Note, that Saginaw laser hardened the housing bore on the cast iron 700 and 800 power gears for best durability.
Jim
Corvettes White
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Jim. thanks for the help. This is for a manual box Corvette, not an integeral power assist. I am not converting the system. I just want to build an alu. housing. And these three boxes all look like they use Saginaw internals based on the look of the outside housing. For those asking; 10 lbs is the projected weight savings. The 5 Grand Sports I believe had such cases. George
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Kid Vette
Master-Baiter
Here's a couple pics I stole off the web.
Doesn't look like they did anything too fancy.
And here's one of the diff.
Corvettes White
Well-known member
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that is it. Now the car is lighter than a producton car, and I expect this to make a difference. Thanks for posting the photos. George
Kid Vette
Master-Baiter
A vintage shot.
turtlevette
The Turdle
A vintage shot.
Is that a single piston caliper? Is that a Chevelle frame?
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