OST-034: Noir Crowning

[oldeskewltoy]

- A package gets dropped at my door.......




No one has told me they sent me anything.....


I open up the box.... it's a head, that much is pretty obvious (size, mass)... but it is well disguised





I manage to remove the tape and get most of the shirts removed... one thing is certain... its 20V....



the heads chambers have been taped over... but a view @ the ports reveal.....



We have a Blacktop head... I've been talking with a client for about 6 weeks concerning his blacktop head... he never did tell me it was on the way...


OST-034: Noir Crowning aka Blacktop




More to come......

[pack]

Ultra cool!!!!!

One day i will do that!

[banpei]

But...but...it's not black!
Nice going. I'm curious on what work you will be doing to this head.

[Bean]

That'll keep you busy Looking forward to the development.

[oldeskewltoy]

thanks guys........


so once unwrapped and set up on the bench.... inspection begins....

Over all the casting quality has gotten much better. Although there still is port-bowl-seat shift, the shift amount - at least in this head, is minimal.

There is one REALLY, and I mean REALLY odd ball bit........ the 3 intake valve seats have NO semblance of an even 3 angle...




Looking into the Blacktop service manual the 3 angles are suppose to be 30, 45, 60. Well the throat cut - 60 degree cut, in essence is the bowl angle and so the back of the port (highest pressure area) has no effective throat cut, while if you look carefully, the throat cut at the short radius is so small, it also becomes more or less insufficient... and the the throat cut between the two... is nothing short of an extreme change - from a width @ the back of the port of almost 5mm, to the width at the short radius of the port of less than 1mm.


I'll been inquiring with a few people as to the best way to address this....

One thing is certain - the factory put a lot more effort in to making the bowls and seats as smooth a transition as the factory could do... the bowl machining marks you see are not by me... those are all factory machining


Adding some more info....

The heads thickness measure.....



My dial caliper is likely off by .001"


and getting a chamber volume




and it is very close to SamQ's 37.8cc measurement.... I'm closer to 38cc





Further inspection......



shows a few issues on the exhaust side... look @ those casting marks.... as they travel from the bowl to the port. Also the small "step" in the machining/casting hurts flow, especially at lower lifts.




More to come........

[oldeskewltoy]

oldeskewltoy Wrote:There is one REALLY, and I mean REALLY odd ball bit........ the 3 intake valve seats have NO semblance of an even 3 angle...

http://ost.ebeans.ch/albums/userpics/100...ffset2.jpg


I'll been inquiring with a few people as to the best way to address this....

One thing is certain - the factory put a lot more effort in to making the bowls and seats as smooth a transition as the factory could do... the bowl machining marks you see are not by me... those are all factory machining

I've spoken with a few people concerning the oddly shaped seats, Although oddly shaped, the back cut will aid filling, and so it should remain.... and it shall





I begin on #4, since the bowls already merge pretty well with the seats, my biggest task is a to "build" a short radius, to minimize the intake guides, and guide bosses, and to gently straighten port/bowl mismatches.



#4 is on the left... you can also see where I've done some mild blending, in the chamber, of the factory machining marks.




And to the exhaust on #4(left).... I seem to remember the info "out there" saying the Blacktop had 35mm exhaust port outlets.... I measured these, they come in around 33.6 ish mm.



The ported one is about 33.75mm..... besides the re-taper, I've also "rebuilt" the shape of the guide bosses to minimize their effect on flow past them. I've also added a minor radius to the exhaust guides to further minimize flow disturbances

The view from the chambers...




With #4 mostly finished(right)... #3 has been cleaned, and #2(left) is still a bit "carbon coated". As I did with the SR20 head, I'll be doing with this one. I'll be mounting this on the flowbench a bit later this week so that I can test the 3 chambers/sets of ports all on the same day, and under the same conditions. This will allow me to quantify the port work.


more to come.....

[Bean]

Once again great work, keep it up and we'll talk/text again soon.

[oldeskewltoy]

from another forum Wrote:That said, it will be interesting to see the tool you conjure to actuate the valves during flowing.

thank you for your contribution....






additionally.... I've made a casting of a port before... and after....




it will help me see the "positive" of my porting/removal. Kinda like these....





more to come........

[banpei]

What do you do with those castings? Are you keeping them for reference or do you send them to the customer afterwards?

[oldeskewltoy]

(08-04-2015 07:18 PM)banpei Wrote:  What do you do with those castings? Are you keeping them for reference or do you send them to the customer afterwards?

I've always kept them.......

BUT... I have given thought to adding a "service"(product?), a complete casting of intake, chamber, and exhaust - assembled, so the client can keep a physical representation of the head work they had received.


and now to the reveal....