I'm about to send my extra P72 head to Portflow and I am debating if I should get my combustion chambers opened a little to match the 84.5mm cylinder bore? Has anybody done this before? Are you guys running stock heads on with no problems? I'm curious because I know opening the chamber is going to decrease my compression ratio but I do not know by how much.

 

dude was gonna create the exact same post i was just thinking about this like 5 min. ago........I guess great minds think alike heheh...

TTT.......... i'm also thinking about the possiblity of doing this?

 

I'm using a stock head, except for type R cams and we should be able to make close to 400hp at the wheels at 18psi. I hope this helped. I'll be able to give more info come monday or tuesday once the car is finished.

 

I did with mine, but it all really depends on your pistons and their dome shape.

 

It completely depends on what brand of pistons you decide to use. Some brands were designed for stock heads, others were designed for heads with matched combustion chambers.

I have a set of 85mm JE pistons for my crvtec motor. The combustion chambers are staying stock because JE said that the pistons I have are meant for use with stock sized combustion chambers.

Check with your piston manufacturer.

 

I think you guys aren't reading the question incorrectly but I will be using dished 84.5mm 9.5:1 RW's. The stock head is designed for a 81~82mm bore cylinder so I am wondering if the mismatch will create weird compbustion problems. So my question is: "Would it be benificial for me to spend the extra $150 to get the chambers massaged out to fit the 84.5mm bore or just leave the chambers the stock size?"

I will be getting the Portflow standard Honda job plus .5mm over-sized valved with the PF dual spring/retainer kit.

 

I went ahead and opened up the CC`s to 84mm. Try a search, there was an excellent topic re: this that went 2-3 pages w/ tons of good info.

Ryan

 

Thanx Ryan!! It took a little while but I found the thread. I am going to spend the extra $150 because I think it will be a worthwhile enhancement.

https://honda-tech.com/zerothread?id=173812&page=2




[Modified by Dee, 3:13 PM 10/11/2002]

 

I remember that thread lol. Damn that was awhile ago.

 

i am using a stock size CC with my 84mm B18c1 block. no problem.