evolve_VIII

iTrader: (11)

Does anyone know the spec for the EVO 8 combustion chamber CC volume? Has anyone actually measured this to be precise?

The reason I am asking now is because Wiseco aparantly posted the wrong specs in the 4G64 form with the 4G63 head. They have 47cc listed when it should be 43cc according to the rest of the catalog.

My head is now bolted on so I cannot measure it. Hoping that maybe someone has a spare one laying around they can measure.

Wiseco and Manley post that the head is 43cc.

Ross and JE have 47cc posted.

03whitegsr

iTrader: (8)

Hit up gearhead on here. He measured his head out during a valve change at one point.

evolve_VIII

iTrader: (11)

Negative. He hasnt logged on since 2005 and no posts about cylinder head volume.

03whitegsr

iTrader: (8)

Hrm, that is the name he usually goes by on local boards but his name might be something else on here as he has definitely posted more recent then that.

Anyway, with some combustion chamber work and the head milled on the stock valves he measured 45cc. With Ferrera valves on the same head it came out to 46cc. Milling the head to the service limit of 0.008" would only reduce the chamber by about 1cc though so it's not a ton.


43cc +/- 1 is probably pretty realistic on the stock head with stock valves without the head being milled any. You are going to get variation in this value as it is part of the casting and not a really well controlled variable.

evolve_VIII

iTrader: (11)

Ok. Thanks for the info. Thats way better than 43. With roughly 45-46cc in at 10:1 compression and not 10.6:1. I have chamber work done to polish it and clean up the head so im guessing im around 46cc then. Cant push pump gas though. Glad I can run both e85 and pump.

03whitegsr

iTrader: (8)

Head work can obviously vary greatly so who knows. I'll send him a message and get him to respond with what he had done on the head. I'm pretty sure his chamber work was fairly similar to what I had done. This included removing the spark plug humps, blending the intake to exhaust valve transistion, and deshrouding/"tuliping" the valves out to the factory headgasket diameter. If so, this is a fairly decent amount of material removal to get it up to 46cc.

JohnBradley

iTrader: (30)

Evo - 43cc nominal
2G Eclipse - 47cc
1G Eclipse - 49cc

Surfacing, chamber work, valve size, etc. can all play a role. The only way to know exactly what it is will be to purchase a CC kit from Summit and see what it does.

gear head

iTrader: (3)

Yeah, I always went off of the 43cm measurement for stock volume, unfortunately I didn't 'cc my head out until after I ground on the chambers. Cleaning up the chamber as 03whitegsr described with Ferrea stock size valves puts me at 46cc.

evolve_VIII

iTrader: (11)

Thank you for the replys and information. Its probably safe to say with my head work and stock valves Im around 44-45.