Combustion Chamber cc's
Turbo Mini Forums

Hello, long term engine build. NA 1413, offset ground 1505 crank 3.325 stroke, cooper s rods, GR 2.874 pistons -6 cc dish. 0 deck height. 276 kent cam looking to run it on pump US gas 92 octane. i have calculated i need a 10.25 static compression ratio. i could dish the pistons some more or change the combustion chamber currently 25cc's with 1.4 valves. I would prefer to grind the chamber and get the 3.5 cc's i need there. But if i do grind the chamber where is the best area to work on? i already plan on extending the chamber out to the 2.9 gasket bore. I also plan on grinding over the top of the intake valve 1.4 in one lobe of the heart shape and lay the wall of the chamber down to 38 degrees (vizard chevy mod) and i plan on doing a similar thing under the intake and extend the chamber down a bit on one side of the spark plug ala a MED head but i still may need 1 or 2 cc more. where would it be best to get that from? thanks

Racecar spelled backwards is Racecar

You may have to opt for steeper chamber walls and loose the beak

Own the day

DO NOT loose the beak. It's only approx 1cc after all.

Thanks Guys so i got a little more precise in the measurements turns out the head is actually at 22.5 cc now so i plan to do the mods i stated above and i expect to get the head up to about 25 cc the rest i plan getting out of the dish in the piston. I have a lathe so i am going to use my radius setup and do a two step dish think of it as two circles. one large diameter circle in the middle and a large radius from the crown to the center radius if i can't get enough there i will do a tapered slot like the vizard pistons to get the rest. thanks Aaron

Racecar spelled backwards is Racecar