Cubic Inches

[rfitzpatrick]

After an engine has been bored 0.040 over -- what's the cubic inches?
Thanks

[katy]

204.5

[d.j. moordigian]

Bore X Bore X Stroke X .7854 X the number of cylinders..

[rotorwrench]

I come up with 204.6 CID. A person can see though that it doesn't change all that much. Even if you go 0.125" oversize it would only be 213.6 CID. I still use bore radius squared X pie X stroke X #of cylinders. It comes out the same way though.

[Patrick L.]

If one wants to increase size then just stroke it. But, I think he was just curious about his new size.

[rotorwrench]

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For a 4-cylinder, it's already pretty big. Even Ford's 800 series tractor engines never got that big but they had overhead valves as a major advantage.

If Ford had used that bore and stroke to make their first V8, it would have been huge at 401 CID.

[David R.]

It is a big bore 4 cylinder. Original Willys Jeep was just 134 cid if I remember correctly.

[d.j. moordigian]

I've built lots of engines, both over square and under square,...the short strokers ran
better. I also thought about building a short stroke Model A with about a 3.750" stroke,
that would make 177 ci with a stock bore. You could run the RPM's up and it would be
easy on the mains,...more like a modern engine.....just a thought. Also a longer rod
would be a plus..
djm

[Jim Brierley]

Changing the stroke on a stock B or C crank weakens them. Putting a large radius on the crank throws would help.

[d.j. moordigian]

Originally Posted by Jim Brierley

Changing the stroke on a stock B or C crank weakens them. Putting a large radius on the crank throws would help.

I agree Jim,...I was thinking about a new Scat crank,...money and age are
the only things stopping me.....lol

[katy]

money and age are the only things stopping me

It's been going around lately.

[Joe K]

Originally Posted by David R.

It is a big bore 4 cylinder. Original Willys Jeep was just 134 cid if I remember correctly.

https://en.wikipedia.org/wiki/Willys_Hurricane_engine

The compression ratio rose from 6.5:1 in the Go-Devil engine to 7.5:1 in the Hurricane engine, although a version of the Hurricane engine was made with a 6.9:1 compression ratio.[3]

Compared to 4.2 in the stock A engine.

Joe K

[David R.]

Joe, I had a CJ2A with a worn out ‘go-devil, and a ‘56 wagon with a ‘super hurricane’ six that I completely rebuilt. If I remember it was 226 and bored out to almost 232 I think. Ran great after rebuilding.

[GerryAllen]

Sincerely you guys are so knowledgeable, we mortals learn so much.

Gerry Birch Bay Wa

[Jim Brierley]

The reason we are knowledgeable is that we are OLD! Maybe not smarter but a little more wise?

[David R.]

The six volt starter wouldn’t crank the new tight six engine. Had to pull it to start it the first time. Ran about 50 easy miles on light oil and changed it. Ended up swapping the manifold and 2 barrel carb for single barrel because the 2 had a tendency to flood on really steep climbs. I took that old Jeep places I never would try to take one now.

[old31]

Originally Posted by katy

It's been going around lately.

Well aint that the truth! Kind of like the coronavirus.

[katy]

The six volt starter wouldn’t crank the new tight six engine. Had to pull it to start it the first time.

If'n the engine was that tight then it hadn't been assembled properly.

[Purdy Swoft]

Many times , a too tight engine won't last very long . The tighter it gets , the friction causes heat and rapid wear .

[David R.]

Everything was assembled with clearances according to factory service manual specifications. (I still have that old manual). Most likely my starter was as worn out as the engine was before the rebuild. Engine ran great for years after.