What's my cubic inch?
 

If my bore is 3.328 with a 4" stroke, is my motor 278.xx ci or am I missing something?
Thank, Joe

Re: What's my cubic inch?
 

278.36

Re: What's my cubic inch?
 

Thanks Tony!

Re: What's my cubic inch?
 

It is the volume of a cylinder - (pi x r sq) X stroke OR (pi x d/2 sq) x stroke.

3.328/2 = 1.664 sq = 2.769 x pi = 8.699 x 4.00 = 34.795 which is volume of one cylinder so x 8 = 278.36

Re: What's my cubic inch?
 

Or just do what I do . . . as I'm lazy . . .

http://www.wallaceracing.com/cid.php

Re: What's my cubic inch?
 

.

This is the way I've been figuring it since I first started reading "Hot Rod Magazine" around 1961.

Bore X Bore X Stroke X .7854 X Number of Cylinders.

3.328 X 3.328 X 4 X .7854 X 8 = 278.36 Cu. In.

Re: What's my cubic inch?
 

Yep, there are always short cuts.

Re: What's my cubic inch?
 

Thanks everyone!

Re: What's my cubic inch?
 

3.328?????? 3.312= 3 5/16. 3.328 = 3 5/16 +.016. Strange bore?
Gramps

Re: What's my cubic inch?
 

Cylinder wear?

Re: What's my cubic inch?
 

3.328/2 = 1.664 sq = 2.769 x pi = 8.699 x 4.00 = 34.795 is volume of one cylinder so x 8 = 278.36

Re: What's my cubic inch?
 

I've seem pistons for 3 5/16" (3.3125") and 3 3/8" (3.375") but 3.328" not so much.

Re: What's my cubic inch?
 

Ron, Unfortunately, Gary (GOSFAST) is no longer with us for me to ask him.
I do remember him telling me he wanted to keep the bore as tight as possible and not remove to much material because it's a blower motor.
There's a note on my paperwork that says "8BA-Std Bore-Needs O/B (.040")
I hope this makes sense. Thanks Joe

Re: What's my cubic inch?
 

3-5/16" (3.3125") is a standard overbore. IF your bores actually measure 3.328", that means that you're going to have roughly 0.016" PISTON CLEARANCE in each bore, which some of us are finding a little hard to understand.....IF the pistons ARE actually 3-5/16" pieces.

Are you sure that your bore isn't 3.228" rather than your stated 3.328? That would make sense as a +.040" oversize. DD

.

Re: What's my cubic inch?
 

Quote: "Are you sure that your bore isn't 3.228" rather than your stated 3.328? That would make sense as a +.040" oversize. DD"


...in which case your displacement would be 261.88 cu. in. :)


Terry

Re: What's my cubic inch?
 

Sounds like it is just .040 over to me . . .

Re: What's my cubic inch?
 

Pistons can be cut down and new ones can be custom made but Egge does make some larger oversizes than 3.3125" in the Mercury type 4-inch stroke. No telling what Gary came up with.

The Egge 3-ring pistons go up from .125" oversize in .010" increments.

Re: What's my cubic inch?
 

V8, I believe you're onto something! I just found paperwork for my compression numbers from Gary and it says the bore is 3.228!
Thank you! Joe

Re: What's my cubic inch?
 

I miss Gary, bought a Stricker assy from him a few years back, still running fine. Ses if your gona run allot of boost it's best to keep a thicker wall. 10 lbs of boos will do more for power then a large Overbore. Have a 294 blower motor putting out 235 hP on 4 lba od boost at 4500. Makes a nice street machine, Wonder what it makes a 5k, but he shut the beast down to sabe it. #$$$$$$$

Re: What's my cubic inch?
 

Ron, I run this motor up to 5500 rpm with 8 lbs. of boost all the time!
Air/fuel is 12.3 at WOT at that rpm
Thanks
Joe

Re: What's my cubic inch?
 

If this was a simple stock rebuild going to .040 over bore would be typical. The fact you have a blower motor it would have been much better being a .125 overbore thus a 3-5/16 bore with the 4 inch stroke. I hope the .040 over pistons are forged {expensive special order} since your seeing 8 pounds of boost. If the pistons are not forged be careful!
Ronnieroadster

Re: What's my cubic inch?
 

Hey Ron, yes, Ross forged pistons, metric rings, Eagle crank and Scat rods.
Gary also fabricated and installed crankshaft main cap supports on all three mains.
My paperwork shows the pistons as "Ross Custom 3.228" $500.00". That was 3 years ago.
Thanks, Joe

Re: What's my cubic inch?
 

Takes allot of guts to do that, This engine has a stock bottom end, But I'd would have gone to 5K at least. On another note a friend has a 294 and it's just a street engine. Everybody has their thing, and 235 HP at 4500 is a very good street engine.
Gramps

Re: What's my cubic inch?
 

It's quite peppy, I'll say!