Got some head pics from Top Power Racing. The Pics show deshrouding of the valves, a technique that allows for better breathing in the head. Maybe someone has some good links to info on deshrouding, but it's a good power making technique, good for high lift/duration cams






To quote Dirtylude, "All deshrouding really means is cutting away the little skirt area that comes on the head around the valves and taking away some material around where the valves meet the edge of the chamber. On a stock head the top of the chamber would be perfectly circular, on those above you can see where they've cut out some material around the valves. I assume you're running larger then 87mm pistons. Since the bore will be bigger you have more room to cut out material around this edge of the valves, which is what they did. "

I am running 89mm pistons, so from the pics you can see how the valves now sort of 'stick out' of the 87mm chamber bore, they have been deshrouded to the full 89mm Now this is a power maker


oh here are my final engine specs if you wanted to know https://honda-tech.com/zerothread?id=471865

 

Do they cc the cc's for you to ensure matched cc volumes?

 

Sound Good, but if you look at the combustion chamber they all look different size.. some got bigger cut.. like the intake side on #3 and #4.


BTW, got some race fuel yet? i still looking it..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by brainwo &raquo;</TD></TR><TR><TD CLASS="quote">Sound Good, but if you look at the combustion chamber they all look different size.. some got bigger cut.. like the intake side on #3 and #4.


BTW, got some race fuel yet? i still looking it.. </TD></TR></TABLE>

Well, looking a different size is different than being a different size I would think.

I don't think I will need race fuel, this lowers the CR but he decked the head 10 thousandths...so we are about the same, but we breathe better etc...I think I will be okay.

 

EVERYtime you do any Alterations to a Cast head you must always CC the displacement of the combustion chambers..

in not doing so may cause certain cylinders to compress with different A/F rations, causing different harmonics which offbalances a crankshaft (exteme case)...

it's best to get every head as close as possible to the same limit.. it has nothing to do with the mill of it....

you don't need to desroud too much either.. doing so can alter your turbulance entering the chamber which helps mix the two key parts.

 

Please don't tell me that its you h22 head.
ok, i don't know if its different cc on each combustion chamber, but i am sure they all different shape. it'll have an affect on flow and combustion.

Bring it to machine shop to have all the combustion chamber match up just to make sure..

 

the deshrouding on this head looks like it was done on a seat and guide machine so we know they are going to be the same because the pilot in which the cutter rides on centers off the guide it also wouldn't take out more than one CC-you are not taking alot of material out so by milling the head .010 you will be bringing the head back down to it's original size .005-.007 per cc of milling.

 

dude what shop you getting all this work done
up here there are not good shops for imports

and when can i look at all this cool stuff
in person

 

oops its top power...but where are they located

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HEAD &raquo;</TD></TR><TR><TD CLASS="quote"> the deshrouding on this head looks like it was done on a seat and guide machine so we know they are going to be the same because the pilot in which the cutter rides on centers off the guide it also wouldn't take out more than one CC-you are not taking alot of material out so by milling the head .010 you will be bringing the head back down to it's original size .005-.007 per cc of milling.</TD></TR></TABLE>

Yeah I never asked. I am an idiot of course this was done at the machine shop that's why the head was decked 10 thousadnths, thank you for reminding me..

oh and for the other guy top power racing is in Toronto, and I can hook you up with them anytime just IM me.