Landracing Forum
Bonneville Salt Flats Discussion => SCTA Rule Questions => Topic started by: Rex Schimmer on June 29, 2009, 08:42:26 PM
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I don't see it in the rule book but is there a tolerance over the specified engine displacements that will allow a slight over bore to clean up the cylinders?? Hope SCTA is not like Nascar!
Rex
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It depends on what you think losing a record is worth? SCTA won't fine you though..... :-D
As far as displacement goes it is in the rule book. If you use "D" engines size as an example the rule book says 261 ci to 305 ci. However the next class ("B") starts at 306 ci. That means your "D" motor can be 305.99999999 ci if you want to get that close, I wouldn't.
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Just remember when you tow back to impound on your record run drive real slow.
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in the motorcycle classes--- P you can bore to your class limit -- M, A, S,SC, and SCS .020 over the class limit is allowed --except any vintage class .050 over the class limit is allowed ---------------and as i understand the rule book any over bore above the class limit will be noted in the log book and the over bore above the class limit will be discounted if you want to move up an engine size class ------------willie buchta
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Rex, are you thinking about running a 750 cc in J class? We sure scared the crap out of ourselves the first time we ran J with a 748cc motor. Didn't do any inch calculations, they called it the 3/4 liter class... when they measured it at 45.7 we nearly croaked... then learned 45.999999999 was OK
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Stainless,
I've been looking at the G class, two liters, 93 to 122 cu. in. The engine I am looking at is 121.87 cu. inches so I have a whole 1.13 cu. inch to "play" with, that is a whole .016 inch over bore! Just "salt dreaming" right now but the G lakester class records looks softer than the stuff you have ran in the J,I, and H classes. Might be able to get 240 hp out of it without mortgaging the house.
Rex
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Stainless,
I've been looking at the G class, two liters, 93 to 122 cu. in. The engine I am looking at is 121.87 cu. inches so I have a whole 1.13 cu. inch to "play" with, that is a whole .016 inch over bore! Just "salt dreaming" right now but the G lakester class records looks softer than the stuff you have ran in the J,I, and H classes. Might be able to get 240 hp out of it without mortgaging the house.
Rex
122 - 121.87 = .230
what bore, stroke, & cylinder count?
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122 - 121.87 = .130 :roll:
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OK guys, Rex has the math the closest... New book, g - 93 to 122.99...
Don't think I would push it past stock bore... the parts will be cheaper and easier to procure
stop dreaming and start building
see ya on the salt 8-)
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Working on some tooling for it right now, hope to have the build table done next couple of months. I know it is $hit of get off the pot time!!!!
Rex
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Showing up at impound with a 25# CO2 fire extinguisher, just to cool off and therefore hopefully shrink the motor a tad, is generally frowned upon. Ditto bringing a giant deep freeze and dropping the motor into cold water -- then to freeze solid.
That's why we've built a motor in the 1350 class -- at 1348 cc. Leave a little room for "just-in-case".
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Jon,,, I think it can actually grow 2 cc's ?? 1348 and a 1350 is close,,, or is it 1348 on a 1350.99 ?
Car displacment works like that... I am 255.xx on a 260.99 with "E" motor and 370.0x on a 372.99 with the "C" motor..
Charles
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Well, okay -- think about it realistically. By the time the motor has cooled enough to be opened up for measuring -- it'll be back to "as-built" dimensions, so trying to shrink it is mostly a joke.
I hope we don't have to resort to such drama. . .
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122 - 121.87 = .130 :roll:
Note to self: Never do math after midnight...
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Sleeve it down or offset grind the crank. Or do both...
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.
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Sleeve it down or offset grind the crank.
Or do both...
Not for bikes.....
My crank has been offset ground (destroked over 14mm) then welded and I have done it before and also debored the stock bore so I know it can be done.
Also have made offset pistons as well.. :cheers:
John
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Also have made offset pistons as well..
John
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how does that work? like stroker pistons?
franey
bub is about 6 wks.; maybe you can still make it.