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Valve seat profiles

Started by sbcharlie, November 24, 2021, 06:35:54 PM

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sbcharlie

You guys that port cylinder heads may start using 40 degree intake contact seat angle and 47 degree exhaust contact seat angles

RTMike

Come on Charlie tell us the rest of the story  :potstir:

sbcharlie


jsachs1

At what lift range is improved ? Valve seat longevity ?
John

Don D

November 26, 2021, 07:29:29 AM #4 Last Edit: November 26, 2021, 07:46:31 AM by HD Street Performance
No disrespect intended but I will stick to the cutters sold by Serdi, Newen, and Goodson. Or in some cases I have customs made. Generally speaking digging into nuances to gain very little, or minor flow bench improvements of a few points, doesn't interest me. That said I am open to changes that bring real significant improvements without loss of durability. Off the shelf angles seem to work for most of the community just fine as well. I have a fixed blade cutter seat and guide machine, Serdi 100, and have no plans or can justify a machine to do designer profiles. Any special profile I have wanted has been supplied by Serdi with drawings I gave them very responsively. In the case of specials changing the top and below seat angles and widths are what have helped net more power without sacrificing anything. I stick to strict rules of my own for seat widths to assure durability. Some heads sent to me had expensive port work and .030" 45° exhaust seats. I have reworked them and so be it if they flow very slightly less. These are street ridden motorcycles and the owners expect to not fool with the engines for a long time.

Admiral Akbar

Having magic seat angles is kind of like having a magic cam.  It may work well when a certain head is with a certain port configuration, certain build.  Does it work for say early / late / CVO 110 TC heads. How much gain is there?  Are the heads CNC ported to ensure consistency between head to head?  What about the other seat cuts? What do they have to be?  What happens when the customer needs to rebuild the head?

Don D

Always wisdom from the Admiral!

sbcharlie

Glad to post on this board again and see the responses. As usual you guys crack me up. 

Admiral Akbar

Quote from: sbcharlie on November 26, 2021, 09:24:25 AMGlad to post on this board again and see the responses. As usual you guys crack me up. 

This is beginning top sound like a "fish story".

rigidthumper

Quote from: sbcharlie on November 24, 2021, 06:35:54 PMYou guys that port cylinder heads may start using 40 degree intake contact seat angle and 47 degree exhaust contact seat angles
Can you show us a flow chart @28" in .050" lift increments what the delta is?
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

FSG

Quote from: sbcharlie on November 24, 2021, 06:35:54 PMYou guys that port cylinder heads may start using 40 degree intake contact seat angle and 47 degree exhaust contact seat angles

I heard from an unreliable source that it's really 41 and 48 when checked with a primary school protractor.

Ohio HD

There was a guy that swore on 48° to 50° on intakes, and on exhaust uses 48° to 55°.      :pop:


https://harleytechtalk.com/htt/index.php/topic,3331.msg31782.html#msg31782





sbcharlie

It's an ever changing world on cylinder head porting

Deye76

Quote from: sbcharlie on November 26, 2021, 05:12:18 PMIt's an ever changing world on cylinder head porting

On everything with Harley Davidsons, but it's a tough crowd. Ask Mike Roland or Doug Lofgren.
East Tenn.<br /> 2020 Lowrider S Touring, 2014 CVO RK,  1992 FXRP

dirt1954

Share the knowledge. I'm not too smart to learn, or at least investigate. Thanks.

Don D

November 27, 2021, 08:52:49 AM #15 Last Edit: November 27, 2021, 08:57:54 AM by HD Street Performance
This 2.2" valve is going in a set of modified corrected geometry Hurricane heads. Stock 2.175" stainless valve was 126g. This valve is 76g. It is coated by Calico coatings for improved durability and has a stellite .290 tip plus 10° bead type locks . This isn't innovation, TI valves have been in use for decades and are now in every Corvette LS production engine. A pair of these cost about as much as my lower cost head porting packages. This 2.2" valve weighs 2 grams less than the 7mm 1.805" OEM valves used on the twin cams. Using a 50° seat and this works for the given application, head geometry, and valve lift. 

sbcharlie

Interesting I have been in motorcycle machine shop business for over 51 years. Have 2 AMA. Number 1 plates with my riders in both singles and twin class. Assist Scott Tomosu to win 3 division on a M8 this year. I travel for Newen all over the world and train major race teams on valve seat profile design. Try to share information here  it's interesting these angles really work

CarlosGGodfrog

The Ford GT40 Lemans 427 used 30 degree intake seats to get better low lift flow. On a street motor, the longevity may be an issue wrt carbon build up. Just an observation.

sbcharlie

Back in the day Indian motorcycle had 35 degree valve seats that one of the reasons they use to spank Harley in the old days. It's great to see Indian beating Harley on flat track racing.  Also BMW used 35 degree seat in some of there Boxer twin cylinder heads

Don D

And Pontiac used 30° seats since the 50s. OK. Is this a selling feature or was there a bona fide benefit? Or was it a mistake? Today most Pontiac heads get reworked with 45 seats and make far more power and torque for many reasons than they ever did, the least of which is the valve seat angle. There are reasons to use different seat angles. I personally don't care about. The port geometry, intended use of the rig, and valve lift provide the decision for most. The same comment can be made about the profiles of the valves we use.

sbcharlie

I'm curious on ti valves what type valve seats you are going to use in most applications they use mold star valve seats. I'm amazed your using 50 degree contact angle. Since your a 45 degree seat guy

sbcharlie

Over past years when was allowed to post on here I brought up offset valve on this site. In my training I see many race teams are now machining offset seat pockets in there performance cylinder heads. Ray Barton and myself have been working on this project for past 2 years and his son had a very successful race season all your metric race heads are now offset Kawasaki has a very interesting seat profile also. I have performed this set up on twin cam heads and the M8 heads with great results

dirt1954

Talk and theory are OK, but documented proof pays for the whiskey. It would be nice to see a side by side comparison where only one thing was changed. Scientific like study.

dirt1954

It seems there is some bad blood here. I'm not trying to instigate more. There is also a tremendous amount of intelligence on this site. Just look at the crankcase pressure data site. Keep up the good work.

Buglet

  Keep up the good work SBC, I think it's good when people try new things otherwise we will still behind times. I see some other professional head ports went with the Newen Seat machine. It's nice to see there are keeping up with the times.