4a head porting question

[gt limited]

The red circles and arrows shown in fig 1 and 2
would you rub out the bumps there to create more CC in the combustion chamber

No flaming please im a noob to this

[ae92gtz]

taking the bumps out will lower the compression, are you going turbo or NA???

[demonics12]

toysport claims porting much can really hurt power on that engine, maybe just a cleanup would help, but i agree with the previous post

[ae92gtz]

if you want to read some good stuff about porting etc check out http://www.theoldone.com/ all you really want to do to the combustion chamber is mirror polish it and take off any sharp edges in the chamber, the polishing gets rid of sharp edges etc which can cause hot spots which lead to pre-ignition, or detonation. The polished surface also reflects the heat back into the chamber which is good for combustion.

[speedy25]

removing metal from the combustion chamber lowers compression. You need to know what you are doing before changing profiles on ANYTHING. The manufacturer does know what they are doing and trying to outguess them doesnt work very well.

-SP

[gt limited]

good read keep info coming i never bother trouble it only clean it

[pnyk33]

my 4a has been port and polish and it runs great.