Inliners International Forums General Discussion Engines im new to inliners so i have some questions

Hello everyone.

Like I said I am new to the inline 6 engines. Have done mostly sbc and bbc's.

So I have some questions. I am finishing up my 496 and am tryin to figure what I want to do next. My machinist had mentioned an inline 6 would be cool and different so here I am.

This is were your all's advice and experience comes in.

My possible plan:

Use a 250 block with a 292 crank.
Turn the rod journals to 2.00 so I can use the 5.7 rods out of the 250.
Bore the block to 4.0 bore and use a 6.0 rod 327 flat top piston.

Here's my math:

250 deck height is 9.150"
Half of the 292 stroke is 2.060"
The pin height of the 327 pistons is 1.385"
250 rod lenth is 5.7"

So 2.060+5.7+1.385 is 9.145"
So the piston would be. 005" in the hole.

My concern was the clearance between the piston and the counterweight but I was told I could turn down the od of the crank on an engine lathe. Which also would help with the balance becaue the rod/piston combo is alot lighter.

Now am I way off with this or can this work? I have some the pieces already but if it wont work then its back to the drawing boards. Thanks.

Check out "nova project progress" under the high performance tab for one example of how to build a stroker in a 250 block. 4.062 stroke, 2.00 crankpins, 6.00 rods, 3.935 bore for 296 inch displacement.

You can't turn the OD down far enough to clear 5.7 rods without cutting into the crankpins. You need to cut the weights around the crankpins if you really want to use 5.7 rods.

The 4.00 inch bore is pushing it with regard to cylinder wall thickness but I've done it with marginal success.

You will have connecting rod interference with the fuel pump lobe. One solution is to use a 292 camshaft and electric pump.

Oil pump and pickup is close too. Alter for clearance or use 292 parts.

I agree with stroker on the counterweight issues. Also, the 5.7 rod with a 4.120" stroke is going to give a very, very poor rod length to stroke ratio. And that coupled with a bore that is 4.000" or bigger is a catastrophe waiting to happen because of the extreme cylinder wall loading and thin cylinder walls.

What I believe Nascar does or other forms of racing, turn the rod journal down to 1.8" ( or there abouts ) the size of Honda rods & use aftermarket rods for Hondas.
Lighter crank, larger radius's on the rod journals = greater strength.
Just some other info,that can reduce the 292 stroke even less & possibly other piston/rod combos,might work, might not, just thought I'd throw that out there.


MBHD

Looks like he is trying to use commonly available components instead of going custom. I would either stick with building an actual 250 or an actual 292, he would be more satisfied with the results that way.