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C460 Piston Damage

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C460 Piston Damage Empty C460 Piston Damage

Post  bosshoss February 28th 2023, 3:18 pm

605 SVO block, Oliver Steel Rods, Lem Evans design Comp solid roller, Charlie Evans prepped C460 heads, Ti valves, Ford Motorsport single Dominator manifold massaged by Charlie, Super Gas Gary Stinnett 1050 Carb on top of a Dedenbear TS4 throttle stop for super Gas NHRA racing.

I know the carb is too small for ultimate performance but this is the way we run them in throttle stop applications trying to get that consistency we all look for.

Just before Covid came along and pissed on our parade i discovered that my tune had somehow deteriorated to the point i was torching pistons, burned through the intake pocket on number three and broke the top ring, crushed the land between top and second.. On the way to total piston desctruction but caught it before it let go ...

Replaced all the pistons, pulled a couple degrees of timing and prepared to hit the track ..

Of course covid slowed us down significantly so i only made maybe 20-25 runs in 2021 then maybe another 40 in 2022

upon inspection after that i noticed a lot of vapour escaping my breather, did a leak down and found number 5 leaking pretty bad so i pulled the head to have a look..

Intake track looks clean and dry across the board, tops of pistons look nice, just a bit of a shadow where they seem to rock up and just touch the heads .005 below deck and a .051 MLS gasket.

Diamond pistons with .043/.043/3mm ring package, top ring on #6 piston was pinched in the groove, and compared to number 5 the free gap has gone to about 1/2 what it was.

Running 32 degrees timing locked out, O2 sensors are reading 12.5 at the finish line... bearings not showing any distress...

Plugs are black and sooty, Autolite racing 3932.

My plan a this point is to install a new set of rings, maybe pull another 2 degrees of timing and 2 or three jet sizes,

Try to get a good read on a fresh set of spark plugs...

Any thoughts from the gurus on here???


thx dkp

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Join date : 2009-08-10

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