curtis
thanks look forward to the info. yes i have used radius intake seats.... they seem to work ok however i have never used non radius seats on these heads but, since reading some of your posts as well as ed's...... i may have to give it a try ..........
Questions on Porting ohc heads!
Moderator: Team
Seth,
I know there's a very good Honda guy in NC that uses a radius intake
seat, .. and he seems to make power, .. but won't talk about it.
If you're using a radius now, .. it would be interesting if a test
could be done, back to back on an engine dyno, ..
The Cycle crowd uses a radius seat anlmost always, .. the R1 stuff
I did I used multi angles and made a fair power improvement.
Curtis
I know there's a very good Honda guy in NC that uses a radius intake
seat, .. and he seems to make power, .. but won't talk about it.
If you're using a radius now, .. it would be interesting if a test
could be done, back to back on an engine dyno, ..
The Cycle crowd uses a radius seat anlmost always, .. the R1 stuff
I did I used multi angles and made a fair power improvement.
Curtis
Race Flow Development
Simultaneous 5-axis CNC Porting
http://www.raceflowdevelopment.com
Simultaneous 5-axis CNC Porting
http://www.raceflowdevelopment.com
Hey did I hear my name,lol.Yeah I use angles seats like Curtis does.I perfer them,due to the fact that everything that's come into my shop or whereever I've worked at gone faster w/angles then radiused intake seats.That doesn't mean that radiused seats don't work,I just probably haven't found out how to use them correctly yet.But here's a pic of my int import valve job for a honda Vtec head.It's a 35,45,65,70.http://images.snapfish.com/34337%3B4323 ... A527nu0mrj
Thanks Curtis,seems to work good for me.lol.Here's a pic of the int valve back cut I use w/that valve job,on a stock valve.45,32,28 http://images.snapfish.com/34337%3B%3B5 ... 5%3Bot1lsi
curtis
are you speaking of RLZ. i have talked to Brad some gave a lil info but is really secretive for the most part. he mentioned that his seat width is .020 are yall this narrow on your seats?
P.S i haven't seen on the bench with a radius seat that backcuts work?
Been thinking about trying some steeper seat angles 50+ degrees.
ED do they work?
are you speaking of RLZ. i have talked to Brad some gave a lil info but is really secretive for the most part. he mentioned that his seat width is .020 are yall this narrow on your seats?
P.S i haven't seen on the bench with a radius seat that backcuts work?
Been thinking about trying some steeper seat angles 50+ degrees.
ED do they work?
The Cycle crowd uses a radius seat anlmost always, .. the R1 stuff
I did I used multi angles and made a fair power improvement.
I'm not so sure how rigorously the cycle crowd has tested their decision. From experience, I know that they don't think as critically as members in other sectors of motorsports and are inclined to simply believe what is offered by brand name builders/porters.
I did I used multi angles and made a fair power improvement.
I'm not so sure how rigorously the cycle crowd has tested their decision. From experience, I know that they don't think as critically as members in other sectors of motorsports and are inclined to simply believe what is offered by brand name builders/porters.
Seth,
Yes I was reffering to Brad, .. I'd test any info from those discussions.
He claims to have been head of cylinder head R & D at Rousch for
several years but nun of the cup guys I know, know him.
Anyone know him from cup? I was trying to get him to help me track
down a friend, .. that's why I ask.
I don't go as narrow as .020", .. I stay around .030" or so, .. I think
it needs to last, .. .. Ed, your take on this.
I'd think twice about the steeper seat angles, .. I have to admit I haven't
given it the development to really see, .. but my thought is the max
valve lift isn't that much, .. and would tend to like a 40º better.
But again, .. I haven't given it the time it needs.
Looking at my port molds and the angle the port comes to the back
of the valve, .. a 50º might work, .. hummm, .. maybe it IS worth
a try.
The biggest thing I have found is making the throat right. Many ported
heads have the throat way too big, .. and when they get here there's
nothing that can be done to them.
Curtis
Yes I was reffering to Brad, .. I'd test any info from those discussions.
He claims to have been head of cylinder head R & D at Rousch for
several years but nun of the cup guys I know, know him.
Anyone know him from cup? I was trying to get him to help me track
down a friend, .. that's why I ask.
I don't go as narrow as .020", .. I stay around .030" or so, .. I think
it needs to last, .. .. Ed, your take on this.
I'd think twice about the steeper seat angles, .. I have to admit I haven't
given it the development to really see, .. but my thought is the max
valve lift isn't that much, .. and would tend to like a 40º better.
But again, .. I haven't given it the time it needs.
Looking at my port molds and the angle the port comes to the back
of the valve, .. a 50º might work, .. hummm, .. maybe it IS worth
a try.
The biggest thing I have found is making the throat right. Many ported
heads have the throat way too big, .. and when they get here there's
nothing that can be done to them.
Curtis
Last edited by cboggs on Wed Mar 16, 2005 10:32 pm, edited 1 time in total.
Race Flow Development
Simultaneous 5-axis CNC Porting
http://www.raceflowdevelopment.com
Simultaneous 5-axis CNC Porting
http://www.raceflowdevelopment.com
I mostly do turbo apps so I tend to keep my seats at 1 mm or .040 wide.I tried a 55 deg int seat on Sav Leone's Hot Rod class car a few yrs ago,he picked up about 1-2 mph,but the guides were cut down and blended into the roof at an angle so the valve deflection was horrendous and would round over the seat almost imediately.I think it would work w/the bowl design like Curtis stated,you can port the int bowls to be very deep and straight like a big chief bowl kinda.Never got the chance to play anymore w/it though Sav moved on after getting valve jobs every week for a while.Here's a pic of the valve job it fit very cleanly w/the bowl and chamber.It's not a closeup but if you save the pic you can then blow it up yourself.http://images.snapfish.com/34338%3B8723 ... B353ot1lsi
This is how the guides were blended you you understand what not to do.http://images.snapfish.com/34338%3B8723 ... B357ot1lsi
I learned alot last year w/a head I did for John Ferguson/James Innes for T4/NOPI,I orginally did the head for a street N/A motor dyno comparision w/an itr head so I keep it small considering the app and kept the stock valve sizes also.Well this combo made just as much power(736 WHP)w/a a much smaller turbo gt40 and B16(PR-3) head not GSR(P-72) which is very preferable,as the hot rod guys were just about a year before,when they were also useing gas and larger valves +.5mm int and +1mm exh and a GSR head.I usto be a believer in a bigger exhaust valve always helped to a point w/turbo blown apps,but am starting to reconsider and am trying a 34 or maybe 35 mm int turbo head this year for a customer.It seemed to find the exit before letts see it it still can w/bigger int valves.
This is how the guides were blended you you understand what not to do.http://images.snapfish.com/34338%3B8723 ... B357ot1lsi
I learned alot last year w/a head I did for John Ferguson/James Innes for T4/NOPI,I orginally did the head for a street N/A motor dyno comparision w/an itr head so I keep it small considering the app and kept the stock valve sizes also.Well this combo made just as much power(736 WHP)w/a a much smaller turbo gt40 and B16(PR-3) head not GSR(P-72) which is very preferable,as the hot rod guys were just about a year before,when they were also useing gas and larger valves +.5mm int and +1mm exh and a GSR head.I usto be a believer in a bigger exhaust valve always helped to a point w/turbo blown apps,but am starting to reconsider and am trying a 34 or maybe 35 mm int turbo head this year for a customer.It seemed to find the exit before letts see it it still can w/bigger int valves.
One of the int roof's had a hole from removing the guide with the roof sp thin so it became a visual test head for me.Of the 4 cyl one is untouched from the way Sav ran it,unblended from the porter that I did the valve job for.I blended in the valve job in the pic I showed.1 is a very big bore just to see what it looked like w/about a 88mm or so bore.And one is the cracked cyc thats got 2 different bowls to show how I port different then we did before.But the 2 cyl's you can still play w/for this test.
