TMI Pistons

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Nov 12, 2016 | 12:45 PM

#16

Kyle Wood

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Joined: Jun 2016

Posts: 246

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From: For School: Big Rapids,MI

i think i found pistons thatll work if i bush the ends of the 400 rods. Kieth black kb177. found a chart that says itll yield a 9.5:1 ratio. i just dont know about valve clearance and im not sure how to figure that out. they are flat tops. and i just have a mild cam (.494 cam lift with 1.73 which is stock rocker ratio)

Nov 12, 2016 | 01:48 PM

#17

HIO Silver

Fleet Owner

Joined: Dec 2009

Posts: 20,678

Likes: 82

From: NorCal

Quote:

Originally Posted by Kyle Wood

i think i found pistons that'll work if i bush the ends of the 400 rods. Kieth black kb177. found a chart that says it'll yield a 9.5:1 ratio. i just don't know about valve clearance and im not sure how to figure that out. they are flat tops. and i just have a mild cam (.494 cam lift with 1.73 which is stock rocker ratio)

Contact KB and ask.... you'll need to know the compressed head gasket thickness because they will ask or at least provide a recommendation. Also ask what the minimum clearance from the valves.

Then verify by installing the head, head gasket, etc. and some modeling clay (even Playdough will work!). Rotate the crank 360 degrees and allow the valves to dent the clay atop the piston. Of course if the rotation suddenly stops then ya know there is zero clearance.

If not, complete the 360-degree rotation and disassemble. Peel off the clay and cut (bisect) where the valves have compressed the clay. Measure. The thicknesses will need to be enough for expansion of the valves and the piston.