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off set seat fixture

Posted: Sun Nov 05, 2017 7:23 am
by sbcharlie
i have been working and developing a fixture to machine off set seat, for Newen BB finally it is done.also i going to adapt this fixture to a Serdi machine
thanks sbchttps://speedtalk.com/forum/download/file.php?mode=view&id=16241

Re: off set seat fixture

Posted: Sun Nov 05, 2017 7:44 am
by jcisworthy
Any more info? I do not see how it works by looking at it.

Is it a cylinder head leveling fixture?

Re: off set seat fixture

Posted: Sun Nov 05, 2017 7:49 am
by sbcharlie
this tool will offset a valve seat a 12 o'clock , 6 o'clock , 3 o'clock , 9 o'clock position i will posting a U-Tube soon

Re: off set seat fixture

Posted: Sun Nov 05, 2017 9:19 am
by jcisworthy
I am guessing the guide along with it?

Re: off set seat fixture

Posted: Sun Nov 05, 2017 1:49 pm
by cgarb
If you get on eBay, there is lots of Chinese seat cutters that would offset seats too...lol. Just not a controlled amount and in the direction you want it to go. What is this for moving a seat over to fit larger valves?

Re: off set seat fixture

Posted: Mon Nov 06, 2017 7:17 am
by sbcharlie
this is a device that moves the angles below the contact angle . moving these angles enhance air flow. honda is now using this in there crf models. i just test a new harley m8 head, with out port work these off set seat enhanced air flow over 20 cfm. of course you can use a pilot when you do this operation.

Re: off set seat fixture

Posted: Mon Nov 06, 2017 7:50 am
by mitch
Im lost if offsetting seat wont you have to do the same with guide
Mitch

Re: off set seat fixture

Posted: Mon Nov 06, 2017 8:26 am
by Dave Koehler
I think what he is saying that it biases the bottom angle or angles in the direction of your choice. Much like you do by hand but more repeatable.
Beyond that I will have to wait for the video to see just how that is pulled off with the guide still in it's original location.

Are offset pilots in our future? Sounds silly but those could be easily made.

Re: off set seat fixture

Posted: Mon Nov 06, 2017 9:11 am
by sbcharlie
i have made them, you can not machine with an off set pilot, they are expensive to make and not that accurate to use. with this tool its easy to use
the fixture captors the machine head, locks it in place then you set your off set

Re: off set seat fixture

Posted: Mon Nov 06, 2017 9:28 am
by Dave Koehler
Video, Video, Video! =D> =D>

Re: off set seat fixture

Posted: Mon Nov 06, 2017 1:46 pm
by sbcharlie
have video made over weekend thanks charlie

Re: off set seat fixture

Posted: Mon Nov 06, 2017 2:56 pm
by dhidaka
sbcharlie wrote:
Mon Nov 06, 2017 7:17 am
this is a device that moves the angles below the contact angle . moving these angles enhance air flow. honda is now using this in there crf models.
How much is the CRF offset and what direction? Intake only or exhaust too?

Re: off set seat fixture

Posted: Mon Nov 06, 2017 4:43 pm
by KnightEngines
I just use 2x dial indicators, lock the head down, turn off the air (so there is no clamp), bump it where I want with a block of wood, turn the air back on & bingo - offset in any direction & amount I want.
Jig looks like it may be a bit quicker tho!

Re: off set seat fixture

Posted: Tue Nov 07, 2017 12:33 am
by modok
As you know USED heads, put in new guides, or due to warpage, the valves will often be a ways off center in the seat. Your bottom angles could end up wide on one side and narrow on the other. Usually that's not desirable, but.....
What if you discover some of them flow MORE? :wink:

Re: off set seat fixture

Posted: Tue Nov 07, 2017 4:20 am
by jcisworthy
It sounds like this is a bowl cutter with the ability to offset in multiple directions. If that is the case, I personally do not see a need for it.

If you offset the bowl cutter and get it to come better in relationship to the runner, the air is not set up properly by the lower bowl angles to enter the seat angles in my opinion.

I would rater have the angles below the seat concentric to the seat. This will set the air up for a better approach to the seat angles as opposed to the runner entering the lower angles then taking a sharp jag into the seat angles.

I prefer to cut the chamber, seat and bowls angles concentric then shape the runner for the best approach to the lowest angle.