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The truth about .051 Medallion pistons
Page 1 of 1
The truth about .051 Medallion pistons
Cox International Thu Feb 23, 2012 12:39 pm
I promised to research the subject so I took apart a Tee Dee .051 and a Medallion .051 and, yes, the pistons are different from each other.
Piston height:
TD - 10.26mm
MD - 10.20mm
Score at bottom:
TD – Wide
MD – Narrow
Piston diameter:
10.40mm on both
However, the MD piston has an OD marginally bigger than that of the TD one as the MD piston jams ½ way up the TD cylinder. My electronic callipers only measure to 1/100th of a mm tolerance.
What the above means is that the Medallion .051 pistons will only fit the .051 Medallion cylinder and not the .051 Tee Dee or .051 Killer Bee cylinders.
Piston height:
TD - 10.26mm
MD - 10.20mm
Score at bottom:
TD – Wide
MD – Narrow
Piston diameter:
10.40mm on both
However, the MD piston has an OD marginally bigger than that of the TD one as the MD piston jams ½ way up the TD cylinder. My electronic callipers only measure to 1/100th of a mm tolerance.
What the above means is that the Medallion .051 pistons will only fit the .051 Medallion cylinder and not the .051 Tee Dee or .051 Killer Bee cylinders.
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Re: The truth about .051 Medallion pistons
John Goddard Thu Feb 23, 2012 1:28 pm
Damn when mine arrives I'll have to get the Hammer out.
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Re: The truth about .051 Medallion pistons
Cribbs74 Thu Feb 23, 2012 1:31 pm
Thanks for following up Bernie,
I have to ask though... Why?
Piston height I get, compression ratio mediallion TD etc. but, why the diameter difference for a sub 300 unit production run it doesn't make sense to do anything differently.
Just wondering, not questioning your findings.
I have to ask though... Why?
Piston height I get, compression ratio mediallion TD etc. but, why the diameter difference for a sub 300 unit production run it doesn't make sense to do anything differently.
Just wondering, not questioning your findings.
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Re: The truth about .051 Medallion pistons
Cribbs74 Thu Feb 23, 2012 1:33 pm
John Goddard wrote:Damn when mine arrives I'll have to get the Hammer out.
Na, just have your machinist buddy modify the cylinder or piston. Or run a small wheel cylinder hone through the cylinder until it doesn't bind and do a good break in.
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Re: The truth about .051 Medallion pistons
Cox International Thu Feb 23, 2012 1:41 pm
cribbs74 wrote:Thanks for following up Bernie,
I have to ask though... Why?
Piston height I get, compression ratio mediallion TD etc. but, why the diameter difference for a sub 300 unit production run it doesn't make sense to do anything differently.
Just wondering, not questioning your findings.
My best guess is that the MD pistons and cylinders were honed in a special production run. I suspect the difference is only like 1/10,000" but enough to make the MD pistons incompatible. I tried a few times really hard to jam the piston in but no go. The TD pistons fits in nicely with the MD cylinder but I suspect compression will be lower.
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Re: The truth about .051 Medallion pistons
Cribbs74 Thu Feb 23, 2012 1:46 pm
Cox International wrote:cribbs74 wrote:Thanks for following up Bernie,
I have to ask though... Why?
Piston height I get, compression ratio mediallion TD etc. but, why the diameter difference for a sub 300 unit production run it doesn't make sense to do anything differently.
Just wondering, not questioning your findings.
My best guess is that the MD pistons and cylinders were honed in a special production run. I suspect the difference is only like 1/10,000" but enough to make the MD pistons incompatible. I tried a few times really hard to jam the piston in but no go. The TD pistons fits in nicely with the MD cylinder but I suspect compression will be lower.
So I guess the advice I gave John will work then......
Makes sense Bernie especially if they were all hand made. Thanks!
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