Engine displacement tolerance?

[Rex Schimmer]

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

[Dynoroom]

It depends on what you think losing a record is worth? SCTA won't fine you though.....

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.

[Brian Westerdahl]

Just remember when you tow back to impound on your record run drive real slow.

[willieworld]

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

[Stainless1]

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

[Rex Schimmer]

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

[AdioSS]

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?

[salt27]

122 - 121.87 = .130 

[Stainless1]

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 

[Rex Schimmer]

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

[Seldom Seen Slim]

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".

[Cajun Kid]

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

[Seldom Seen Slim]

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. . .

[AdioSS]

122 - 121.87 = .130 

Note to self: Never do math after midnight...

[NathanStewart]

Sleeve it down or offset grind the crank.  Or do both...