hello guys,
i'm building a b16 with darton 84.5mm sleeves, and i wanted to know what do you guys usualy do with the combustion chamber?
do i just need to enlarge the chamber to 84.5?
thanks

 

you said your block is sleeved to 84.5mm.

what do you mean by enlarging it to 84.5mm when its already 84.5?

 

The combustion chamber is in the head not
The block.....

 

Most people leave the combustion chamber alone without any adverse effects. If you were using a GSR head the quench pads are inside the bore anyways.

https://honda-tech.com/forums/all-motor-naturally-aspirated-44/chamber-size-cylinder-bore-size-question-3076576/

 

that's what i assumed about the quench pads too

thanks alot

 

im at 84.5mm stock casting b16 head. no issues with leaving the combustion chamber. i do use the golden eagle hg's exactly bore matched to the block

 

It really depends on the piston design. If you are running some serious domed pistons it will matter without a doubt. Ideally you want the chamfer all the sharp edges would be near the fire ring. Typically there isn't an issue if the cylinder bore is larger than the combustion chamber. Sometimes there can be an issue depending on how far a head porter goes with deshrouding the valves though.

I am no cylinder head expert but there may be some sort of a flow (be it air or flame travel) affect running a smaller combustion chamber that isn't of the pented with quench design. The quench pads offer a "squish" that *should* be calculated when building the engine. Too much can be just as negative as too little clearance to a point. Many, many, MANY variables to consider when building an engine.

Short answer - You should be fine.

Long summary answer - When every last bit of power is wanted, it will matter.