as post says i have a 2000 b16 head i was using on a 84mm sleeved block that was used for a turbo setup i am now going allmotor and i have a stock gsr bottom end. I figure that the 84mm combustion on 81mm gsr is lowering the compression ratio a bit. So i am going to put b16 piston or itr pistons in the block. I was wondering if anyone has any expirience with bigger combustion chamber than block?


Modified by bounty359 at 9:52 AM 4/7/2005

 

bump

 

could really use some opinions

 

You may run into some detonation issues as the sharp machined edge of the cylinder/deck heats up. I don't know this honda specific stuff too well, but from a general engine building point of view, its not a good idea.

 

https://honda-tech.com/zerothread?id=1191665

I talked to the machine shop who said that the combustion chamber(the first pic in the above link has a good pic) was made completely round removing the sections behind the intake valve and exhaust valves during the port and polish and valve job so instead of the sharp corners it is rounded

 

The lip I was referring to would be the lip on the block. If you have a 84mm combustion chamber on a 81mm bore you are going to have a 1.5mm lip of deck surface that is exposed to the head of the combustion chamber. This is going to become a major heat riser when the engine is under wot conditions. Additionally you should CC your combustion chambers, and cylinders at TDC (factoring in any vavle reliefs or low deck issues), as well as add in the head gasket volume to see exactly what your compression is going to come out at. In my experience with DOHC head designs in general, there is very little work that needs/should be done with them and most people who do extensive "porting" just end up screwing things up. Head gasket sealing may become another issue to keep in mind.

 

thaks for the help

 

Not a problem. Always nice applying domestic info in the Honda world. Slowly i'm getting you honda guys figured out.... ;-)