tons of porting issues/questions!!

well diggin into my head/intake porting project and have a few questions maybe you could all offer me some answers to:

here it goes (sorry kind of long)......

backcutting the valves?? what does this mean? i saw it in grassroots
motorsports article and they said this yields huge gains per hour spent and
should always be done i can post this article also if anyone wants it


radius the face of the exhaust valve for ow lift flow gains?? how much?
how much material to grind off??
i believe this means just grinding a littl eangle on the face of the exhaust valve to blend it into the seat a little right??


i know flattening the intake port and widening it can cause good gains,so
does flattening the roof of the xhaust port and widening that do the
same thing? also raising the exhaust port roof helps flow, should the
intake port roof (to increase the straigth shot "window") or the intake
floor (air is heavy and flows mostly on the intake floor
because of the direction of the air) what should be done to the intake port
i have seen pics of E7TE ports on workmonster.com and their ports almost seem
to have a general triangle shape to them,

maybe if someone has a set of TFS or aftermarket heads in their garage
they could check them out for me and tell me if the ports are certainly
square of maybe have abit of a triangle shape

only running an E cam and some 1.7 roller rockers, advise for or against
grinding down the valve guide bosses?? maybe just a little?? maybe grind them completely away??


heard of a tooled finish where the intake becomes increasingly smooth as
port size shrinkg and port velocity increases because rough port walls are
no longer needed to keep fuel atomized, this is common in race harley engine and makes sense
what do you guys think?

does a vane behind the exhaust port valve guide boss any help? i have heard that leaving a vane behine the intake valve guide boss helps direct air a bit
so there isn't too much turbulence behind the intake valve guide boss and
smooths flow
would this help on the exhaust valve guide boss in any way?


smoothing the combustion chamber... not worth the loss of compression? i'm using sotck E7TE heads with stock valve size.



i know each of these is probably just a little gain but they add up!! maybe someone with a flowbench out there or professional porter could answer some of my questions and help me out!!?? i've kind of been wondering about this stuff for a long time
i know each of these takes a lot of time, but that is the one thing i've got plenty of!! not in any hurry to get these done, would rather spend the time to do it the best i can.

this forum seems kind of dead lately where is everyone??

i know this is quite a bit of info but maybe someone knows of a good book they could recommend or maybe another site that this would be more suited to be posted on?? where did all you guys learn about porting from when you did your heads??

well diggin into my head/intake porting project and have a few questions maybe you could all offer me some answers to:

here it goes (sorry kind of long)......

backcutting the valves?? what does this mean? i saw it in grassroots
motorsports article and they said this yields huge gains per hour spent and
should always be done i can post this article also if anyone wants it


I wouldn't say huge gains but it helps. The seat angle is 45 degrees, back cutting narrows the seat width and brakes the edge.


radius the face of the exhaust valve for ow lift flow gains?? how much?
how much material to grind off??
i believe this means just grinding a littl eangle on the face of the exhaust valve to blend it into the seat a little right??

I chuck the valve in a lathe and use a file to radius the leading edge of the valve into the seat. The valve margin isn't very thick so you won't be able to remove much.


i know flattening the intake port and widening it can cause good gains,so


Widening it helps but don't flatten it just to do it. The short turn when done correctly will dictate the floor height.


does flattening the roof of the xhaust port and widening that do the
same thing?

The exhaust port is totaly different.

also raising the exhaust port roof helps flow

Not nesessarly, the roof needs to have near the same conture as the floor. Raising the roof may decrease the pressure on the floor causing the port to back flow.

, should the
intake port roof(to increase the straigth shot "window&quot[img]/phpBB/images/smiles/icon_wink.gif[/img] or the intake
floor (air is heavy and flows mostly on the intake floor
because of the direction of the air) what should be done to the intake port

The intake port openings dont need to be much larger than stock. Most of the matieral that needs to be removed is deep into the port and requires a 4 inch shank carbide.

i have seen pics of E7TE ports on workmonster.com and their ports almost seem
to have a general triangle shape to them,

maybe if someone has a set of TFS or aftermarket heads in their garage
they could check them out for me and tell me if the ports are certainly
square of maybe have abit of a triangle shape

only running an E cam and some 1.7 roller rockers, advise for or against

grinding down the valve guide bosses?? maybe just a little?? maybe grind them completely away??

There is little or no gain by removing the guide. It needs to be there to support the valve


heard of a tooled finish where the intake becomes increasingly smooth as
port size shrinkg and port velocity increases because rough port walls are
no longer needed to keep fuel atomized, this is common in race harley engine and makes sense
what do you guys think?

Yes,I usually finish the bowls, short turn down to the 60 degree angle below the seat with a 240 grit roll. The closer to the valve, the smoother I make the port

does a vane behind the exhaust port valve guide boss any help? i have heard that leaving a vane behine the intake valve guide boss helps direct air a bit
so there isn't too much turbulence behind the intake valve guide boss and
smooths flow

Generally this helps but because the E-7 port is so small I do not leave anything behind the valve.

would this help on the exhaust valve guide boss in any way?

Leaving a tail behind the exhaust guide helps


smoothing the combustion chamber... not worth the loss of compression? i'm using sotck E7TE heads with stock valve size.

There is not much gain by polishing the chambers.


i know each of these is probably just a little gain but they add up!! maybe someone with a flowbench out there or professional porter could answer some of my questions and help me out!!?? i've kind of been wondering about this stuff for a long time
i know each of these takes a lot of time, but that is the one thing i've got plenty of!! not in any hurry to get these done, would rather spend the time to do it the best i can.

Do as much research you can before you start grinding. Hope this helps.

http://hometown.aol.com/valakoracehe...raceheads.html


<font size=-1>[ This Message was edited by: JimV on 4/28/05 2:19am ]</font>

THANKS!!!! i'm sure that took you along time, i really appreciate, i feel a lot better now, wanted to go a little further than just grind a little here and there, but didn't want to screw anything up, so thanks for help bro!!!

those modified stock size valves are super interesting to me also, i'll be emailing you with that website to talk more!

thanks for you help once again, i notice you said that leaving a small "vane" behind the exhaust valve guide helps flow but i dont really see it in your pics on your website, i think i'm not looking at the right place, do you mean leave a little ridge on the side of the exhaust valve guide that faces towards the head of the valve or leave a vane "behind" the valve guide on the side towards the exhaust port at the header flange??

acutally never mind, i just answered my own question[img]/phpBB/images/smiles/icon_spin.gif[/img] i see the little vane behind the exhaust valve at the bottom of this page

http://hometown.aol.com/valakoraceheads/page10.html

thanks!!!![img]/phpBB/images/smiles/icon_spongebob.gif[/img]

No problem!

The radius on the exhaust valve is on the chamber side of the valve where its normally sharp, you want to smooth that in a radius. Only smooth it. There is alot of flow in the chamber as well, unshrouding the valves. 90% of intake flow is right in the short turn of the intake port.
Brian
[addsig]