Help with displacement math

[Tim Ayers]

Sadly, I'm embarrassed to admit that math is subject that I struggle with. After doing some Google searches, I still can't quite figure this out.

If a bore measures 3.30", what does that equate to as a fraction in regards to overbore from the stock 3 3/16" bore? 3 3/10" is what I'm getting, but that doesn't seem to make sense with typical overbore sizing.

Thanks,

Tim

[Mart]

You might want to remeasure. that works out to .1125" over which is an oddball size.

Just take 3.1875 away from 3.3 and you get .1125.

I start by dividing 3 by 16 to get the fractional equivalent .1875. then I add the 3 to get 3.1875 and I use that in the calculator.

I'm old enough to have learnt fractional stuff at school.

Mart.

[Tim Ayers]

Originally Posted by Mart

You might want to remeasure. that works out to .1125" over which is an oddball size.

Just take 3.1875 away from 3.3 and you get .1125.

I start by dividing 3 by 16 to get the fractional equivalent .1875. then I add the 3 to get 3.1875 and I use that in the calculator.

I'm old enough to have learnt fractional stuff at school.

Mart.

Mart:

Thank you! Let's assume my measurement is correct. If the bores are in good shape, how likely is it that a final bore of +.125" over will clean them up?

I want to build a 276 so +.125" by 4" stroke is the master plan. I'd rather not go larger than +.125" if I don't have to.

[flatheadmurre]

Depends on where you measured the 3.30...if it´s the absolute largest then it may work out.
You have 12 thousands left for final size.
You need about 3 thousands for honing to desired finish...

[Tim Ayers]

Originally Posted by flatheadmurre

Depends on where you measured the 3.30...if it´s the absolute largest then it may work out.
You have 12 thousands left for final size.
You need about 3 thousands for honing to desired finish...

Thank you.

[Ronnieroadster]

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Tim pistons can be made to the dimension of your final bore if its already honed and straight. If theres a tapered dimension then the bore can be increased to the 3-5/16 diameter and if theres any other surprises any size piston can be made to fit the needs of the block.
Ronnieroadster

[Ol' Ron]

Egge makes avery good 3 ring piston in several over sizes for the 3 5/16 bore .124 over). .145, .155 to save these blocks I have a set of the .145 pistons in my truck, which gives 279.4 CI. I call it a 280 for short. the rest of the engine is stock EAB cam and head with a 4" merc crank 2GC and Chevy distributor.

[Tim Ayers]

Originally Posted by Ol' Ron

Egge makes avery good 3 ring piston in several over sizes for the 3 5/16 bore .124 over). .145, .155 to save these blocks I have a set of the .145 pistons in my truck, which gives 279.4 CI. I call it a 280 for short. the rest of the engine is stock EAB cam and head with a 4" merc crank 2GC and Chevy distributor.

Thanks Ron. Will be talking to Ronnie Roadster to get this done.