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Old 05-03-2016, 09:50 PM   #1
68Cadillac
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Default Port, Polish, Headwork: Order of operations

Looking at doing port work on my heads.



^^^ Not my work or heads. Fuji K's work.

For those more experienced with head work what's the ideal order of operations to perform the work so I'm not stepping on my own work? I'm looking for a light port job. That is, removing the casting flash, blending the throats with the bowls, removing sharp steps in the metal where the air flows.

1. Check Head Deck for level and deck as needed
2. Replace Valve guides
3. Remove casting flash and sandroll intake ports
4. Remove casting flash and sandroll exhaust ports
5. Port work on dogleg exhaust
6. Blend throat into valve inserts, removing those steps and bumps and machine marks
7. Blend in the steps near the valve heads in the combustion chambers, especially around the exhaust valve seats "Deshroud Valves"
8. Blend in other sharp corners on the combustion chamber without removing too much material just so there's not a sharp edge that can get really hot and cause detonation.
9. Polish or recut valve seats to match valves
10. Clean
11. Clean some more
12. Install valves, springs, oil seals, retainers
13. Measure for shimless-buckets
14. Order buckets
15. Install buckets and camshafts


Is there a better order to do this in?
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Old 05-04-2016, 04:12 PM   #2
68Cadillac
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Old 05-04-2016, 05:52 PM   #3
fwillyj
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-this is my typical procedure for doing B25, D25, W25, V25B style heads
-----------------------------------------------------------------------------------
1---remove all oil galley plugs---requires torch heat.

2---if guides are junk---remove valve guides, replace with new Subaru guides, hone slightly to size of valves to be used.

3---shorten intake divider walls 1---includes axe edge blend to ports out to entrances nearly to final condition.
-----includes slant the intake valve guides to match the roof contour.
-----very minimal metal removal from any place in the intake port.

4---port & polish heads:
-----mildly blend all valve bowls up to the crest of the floors
-----port & polish the exhaust floors from the exit ends.
-----port & polish the exhaust roofs from the exit ends.
-----port & polish the exhaust front side walls from exit ends.
-----port & polish the exhaust rear side walls from exit ends
-----leave the exhaust floor crest radius's for very last final blending.

5---machine valve seats for new oversize valves or for stock diameter.
----sink valves enough to get seats to outer edge of the valves.
----intakes get 45/60/75/80 angles
----exhaust get 45/54 angles only----hand blend exhaust right up to bottom of the 45.
----don't use any top cut on chamber side.
----maintain all intake depths to within .002" total variation.
----maintain all exhaust depths to within .002" total varation.
----maintain all valve seat runouts to less than .0009".
----number all valves to each specific cylinder---and front or rear.

6---hand blend exhaust bowls to bottom of seats after machining of the seats.
----hand blend intake to top of the 80 degree angle.

7---lightly fluff & buff chambers and blend the area around the sparkplug threads.

8---flowtest one head twice---as received and again after totally finished with porting etc----for before and after flow numbers.

9---mill both heads minimum amount to get a clean surface (.003)
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Old 05-05-2016, 11:07 AM   #4
albersondh
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Quote:
Originally Posted by fwillyj View Post
-this is my typical procedure for doing B25, D25, W25, V25B style heads
-----------------------------------------------------------------------------------
1---remove all oil galley plugs---requires torch heat.

2---if guides are junk---remove valve guides, replace with new Subaru guides, hone slightly to size of valves to be used.

3---shorten intake divider walls 1---includes axe edge blend to ports out to entrances nearly to final condition.
-----includes slant the intake valve guides to match the roof contour.
-----very minimal metal removal from any place in the intake port.

4---port & polish heads:
-----mildly blend all valve bowls up to the crest of the floors
-----port & polish the exhaust floors from the exit ends.
-----port & polish the exhaust roofs from the exit ends.
-----port & polish the exhaust front side walls from exit ends.
-----port & polish the exhaust rear side walls from exit ends
-----leave the exhaust floor crest radius's for very last final blending.

5---machine valve seats for new oversize valves or for stock diameter.
----sink valves enough to get seats to outer edge of the valves.
----intakes get 45/60/75/80 angles
----exhaust get 45/54 angles only----hand blend exhaust right up to bottom of the 45.
----don't use any top cut on chamber side.
----maintain all intake depths to within .002" total variation.
----maintain all exhaust depths to within .002" total varation.
----maintain all valve seat runouts to less than .0009".
----number all valves to each specific cylinder---and front or rear.

6---hand blend exhaust bowls to bottom of seats after machining of the seats.
----hand blend intake to top of the 80 degree angle.

7---lightly fluff & buff chambers and blend the area around the sparkplug threads.

8---flowtest one head twice---as received and again after totally finished with porting etc----for before and after flow numbers.

9---mill both heads minimum amount to get a clean surface (.003)
How are holding .0009 concentricity, what tooling/process? What tool are you verifying this with? This is impressive, as results I have seen and paid for, have not even come close.
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Old 05-05-2016, 04:49 PM   #5
fwillyj
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-I use a tenth reading dial indicator mounted onto a fixture I built and this fits onto the valve guide pilots.

-I also have made several very precise flattop pieces pieces that rotate under the dial indicator tip with a register surface off the seat.

-sort of similar to the high dollar Sunnen seat runout gauge.

-there are a few other details that help with the process but basically it's matter of knowing and believing that my stuff is as perfect as it can be----and it's somewhat time consuming so it requires plenty of patience.
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Old 05-05-2016, 05:40 PM   #6
albersondh
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Quote:
Originally Posted by fwillyj View Post
-I use a tenth reading dial indicator mounted onto a fixture I built and this fits onto the valve guide pilots.

-I also have made several very precise flattop pieces pieces that rotate under the dial indicator tip with a register surface off the seat.

-sort of similar to the high dollar Sunnen seat runout gauge.

-there are a few other details that help with the process but basically it's matter of knowing and believing that my stuff is as perfect as it can be----and it's somewhat time consuming so it requires plenty of patience.
That is impressive. Got any pics of your rig and/or work you would be willing to share?
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Old 05-05-2016, 07:40 PM   #7
fwillyj
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-this nasioc website does not allow us to insert pictures.
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Old 05-05-2016, 08:33 PM   #8
68Cadillac
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Imgur is a free photo hosting site. Upload your images there, then link them here.
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Old 05-05-2016, 09:16 PM   #9
spoolinsti05
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I use photobucket still lol
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Old 05-06-2016, 08:06 AM   #10
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Quote:
Originally Posted by spoolinsti05 View Post
I use photobucket still lol
I love photobucket lol

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Old 05-06-2016, 09:17 AM   #11
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Quote:
Originally Posted by Turbo_Mike View Post
I love photobucket lol




Ouch what happened with that? Leaky valve seat?
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Old 05-06-2016, 09:45 AM   #12
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Quote:
Originally Posted by spoolinsti05 View Post
Ouch what happened with that? Leaky valve seat?
Bugeye heads. BC272 cam swap without measuring or changing buckets. Valve was a bit tight.

Lasted 26k miles after cam swap like that, and had roughly 100k on the heads before that.
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Old 08-11-2018, 10:21 PM   #13
rlew21
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Bringing this thread back from the grave! What purpose does shortening the divider between the ports serve? I'm assuming that a shortened divider creates a "short runner" with better high rpm flow/response and a longer divider would be more suited for low rpm. Then again the dividers are between runners on the same cylinder so maybe the length doesn't matter as much as maintaining a low angle (keeping laminar flow) while the gasses split/meet as they enter/exit the runners?

It looks like on 68caddilac's heads the exhaust port divider was shortened, but not the intake (opposite of what fwillyj does). I imagine that this helps even out the flow between the dog-legged exhaust port and the other more straight ports. I'm considering doing this to my heads, but don't have access to a flow bench to confirm results. Leaning towards just cleaning up the casting to a polish on exhaust, 120 grit on intake, r.emoving ledges on the seat/bowl area, edges around the valves, and polishing the CC.

Any thoughts on shortening the port dividers?
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Old 08-12-2018, 10:01 AM   #14
fwillyj
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-here is an old link to some of my Subaru machining back in 2006.

http://www.ryanbrownracing.com/Bill_Jones_Page_14.html

------------------------------------
-I have since improved my skills and learned how to better deal with the machining of seats.


-this was all before we were doing the shortening of the intake divider wall.

-the method I used for shortening the divider wall was worth around a positive 10 CFM gain.

-issues here is that divider wall is a major support to the entire combustion chamber surfaces so the wall can be narrowed up much or fully removed.

-so the amount of wall that was cut back was NOT the full one inch height of the divider---but was a narrowed shape that left as much chamber support as possible.

-I don't have any way to show pictures of the divider walls.
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Old 08-13-2018, 03:11 AM   #15
rlew21
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fwillyj: That's a pretty cool link you shared, definitely makes me want to try and machine some heads myself! How did you have the heads fixtured? I'm guessing they're resting on angle blocks and held down to the bed with some sort of custom t-slot nut. I might try to convince the school to get some of the tooling so i can play with our under-utilized HAAS

What are the ticks you learned on cutting the seats since that post? I've read about some guys opening up the throat of the valve seats on the exhaust side (especially with oversized valves) to help improve flow

I don't have the courage to cut seats/ ream the guides on the good subaru heads yet, but have a set of junk heads and might play around with some cbr600 heads if that goes well :-)

With shortening the divider wall are you saying you'd cut it back in a crescent shape (looking from the side) with the center measuring 1" further back from original or that the divider wall was cut less than 1"? it sounds like a whole lot of material to remove, and a good bit more than I'd feel comfortable doing right now, but if there's an easy to measure benchmark on how far back I can cut it I might just give it a shot. Like I mentioned I don't have a flow bench so I don't want to make drastic changes that could create a significant variance in the flow between the different ports.

Would you recommend shortening the divider on the exhaust side or are there not any gains to be had there? As someone who's just getting into this it seems like in order to get an engine that's well balanced between the different cylinders that getting more flow out of the dog-legged exhaust ports would be the biggest factor (talking about a reliable street build here)
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Old 08-13-2018, 10:19 AM   #16
fwillyj
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-this link shows my tilt tables that I built for my mill---and an aluminum piece that is doweled that I made specifically to set up Subaru heads on my mill.

http://www.ryanbrownracing.com/Bill_Jones_Page_12.html
-----------------------------------------------
----roof of that divider wall breaks thru into the water jacket so there needs to be a full length hump.


---I do 50 and 80 angle cut using a long 1/2" ball nose end mill cutting 1" away at the original center area of the divider--then hand blend and leave the roof with a nice rounded area of the length of roof cut.
-----------------------------------------------

---I use a .0001" dial indicator to measure runout---dead Sioux pilots with a dot of heavy grease to lube the cutter head.


---built my own runout gage mount fixture and built my own various sized runout sweepers that sweep the seat diameter and the runout out gauge rides on top of that precisely ground flat surface.

---I built a different method of holding the ball heads up into the driver head instead of that stiff bent wire spring I once had.

---I religiously test every seat every time it gets touched with the cutter or anytime I touch the seat with a Sioux stone.


---Valve seats are a very tedious job---especially when you are attempting to get all the seats the same exact final depth---with virtually zero runout like maybe a total tolerance of .0003".

----------------------------------------
---I would not even consider messing with the exhaust divider wall---and lowering the lower corner of the dogleg doesn't take much to get into the water jacket.
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Old 08-14-2018, 07:01 PM   #17
fwillyj
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---this link shows some of the evolution of my valve seat runout gauge that measures accurately to .0001"---even after a number of years it is still a jewel.

http://www.ryanbrownracing.com/Bill_Jones_Page_9.html
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