Chamber Mods vs Material Volume Removed Question

[skinny z]

I'd posted earlier regarding the tools required to clean up the chamber's in my aftermarket iron heads.
While I had my question answered it also gave me some real insights into the kind of mods that might be done.
So, further to that, the next question is, how much material can I expect to be removed if I were to go from the pictures of my heads , with a measured 65.4 cc chamber, to one of the forms in the following pictures.
I would expect maybe 2 cc's. Sound reasonable?
It was suggested that my objective is to smooth the sharp edges from the top relief cut which was added in an effort to reduce chamber volume.
I'm not sure if there's any substantial valve shrouding to the chamber walls although I haven't physically measured (but I intend to).

Chamber 1.jpg

Mine

Chamber 2.jpg

Mine

20201214_114405.jpg

Proposed

C19697C0-4B6A-41AF-BC7A-D4AE05F96BDA.jpg

Proposed

[maxracesoftware]

just do the least amount of blending all around the Seat's top angles
into a smooth transition into the Chamber .

sort of like the "Proposed" 1st picture's blending
download/file.php?id=28653&mode=view

[skinny z]

just do the least amount of blending all around the Seat's top angles
into a smooth transition into the Chamber .

sort of like the "Proposed" 1st picture's blending
download/file.php?id=28653&mode=view

Any idea of the volume of material that might be removed?
Would you think 1 or 2 cc's?
As you suggest, I intend to do the least amount but yield reasonable results.

[maxracesoftware]

Any idea of the volume of material that might be removed?
Would you think 1 or 2 cc's?
As you suggest, I intend to do the least amount but yield reasonable results.
Kevin

Yes, 1 to 2 CC's would be a pretty close guess
use 2 old Valves you ground both valve margins down to razor sharp @ a 50 or 55 deg seat angle
to protect your Valve Job seats (45deg)

i had a similar problem come up that a new local machine shop
was doing a Valve Job on #292 Turbo Heads when all of a sudden the Spindle dropped down and sunk the Seats about 0.140" down
ruined that Head ... then they did the 2nd Head ... same thing happened to it .. ruined that Head too
They installed Seat inserts , but they all leaked water ... so Customer gave me the Heads to experiment with .

so i've been wanting to try a 50deg VJ Seat angle on a #292 Turbo Head
and i had a lot of seat top angle to blend into the Chamber (0.140" +), and it worked pretty well , had decent Flow Numbers
for such sunken Seats ... the "blending" into the Chamber does the trick !

[skinny z]

Any idea of the volume of material that might be removed?
Would you think 1 or 2 cc's?
As you suggest, I intend to do the least amount but yield reasonable results.
Kevin

Yes, 1 to 2 CC's would be a pretty close guess
use 2 old Valves you ground both valve margins down to razor sharp @ a 50 or 55 deg seat angle
to protect your Valve Job seats (45deg)

i had a similar problem come up that a new local machine shop
was doing a Valve Job on #292 Turbo Heads when all of a sudden the Spindle dropped down and sunk the Seats about 0.140" down
ruined that Head ... then they did the 2nd Head ... same thing happened to it .. ruined that Head too
They installed Seat inserts , but they all leaked water ... so Customer gave me the Heads to experiment with .

so i've been wanting to try a 50deg VJ Seat angle on a #292 Turbo Head
and i had a lot of seat top angle to blend into the Chamber (0.140" +), and it worked pretty well , had decent Flow Numbers
for such sunken Seats ... the "blending" into the Chamber does the trick !

Thanks for that.
These heads are supposed to have a pretty good valve job. 5 angles. Reputable shop. Plus the relief cut that came before.
Flow on the intake is 255@.500" and a small 170-175 cc port but drops a bit (245) past that.
Once I have them disassembled I'll have another look at their work.
I have a couple of old valves modified and ready to go. Haven't checked their fit yet but should be good to go.
Thanks again.
2 cc would make a real difference as there's nowhere to go otherwise as it already has a .040" deck. Would like to keep a 5 cc piston and compression about 10.2:1.
Nothing is finalized yet though.

[steve cowan]

Kevin,
That photo is a 50 deg seat with 40 deg top cut 0.100" wide blended into chamber,
Larry gives excellent advice

[In-Tech]

i had a similar problem come up that a new local machine shop
was doing a Valve Job on #292 Turbo Heads when all of a sudden the Spindle dropped down and sunk the Seats about 0.140" down
ruined that Head ... then they did the 2nd Head ... same thing happened to it .. ruined that Head too
They installed Seat inserts , but they all leaked water ... so Customer gave me the Heads to experiment with .

Ouch, big ouch

[maxracesoftware]

Ouch, big ouch
Heat is energy, energy is horsepower...but you gotta control the heat.
-Carl

his #292Turbo Heads were ran for 2 years ,
they had no cracks , they were perfect "as is " ,
then he had his new Machine Shop Buddy refreshen them up .
now they had a few Exhaust and Intake Seats installed after their Machine's Spindle messup ,
all those seat inserts leaked water .

here's the same #292 Turbo Heads after i redid the Valve Job
to 2.080/1.600 combo with 50 degree seat angles
will Post a separate Thread later on them with FlowSheets + more detailed Pictures

Turbo292_SunkenSeats1024x1365.jpg

Turbo292_SunkenSeats1024x768.jpg

Turbo292_SunkenSeatsAfterPorting.jpg

[skinny z]

Kevin,
That photo is a 50 deg seat with 40 deg top cut 0.100" wide blended into chamber,
Larry gives excellent advice

Hi Steve.
That would be this picture?

20201214_114405.jpg

Pretty sure these are yours. Which heads?

[skinny z]

Turbo292_SunkenSeats1024x768.jpg

Larry. Question for you.
Do you get that contact imprint from lapping them on to the bluing or do you have to touch them with a stone to get that detail?

Turbo292_SunkenSeats1024x768.jpg

I've checked mine just by lapping them with compound but don't get that detail.

[maxracesoftware]

Larry. Question for you.
Do you get that contact imprint from lapping them on to the bluing or do you have to touch them with a stone to get that detail?
I've checked mine just by lapping them with compound but don't get that detail.
Kevin

i Lap them for 3 to 5 seconds max with Clover 280 Grit compound
while the Vertical Mill is still centered on the either the Intake or Exhaust valve guide
and with the Vertical Mill's Table is still locked in place ,
the lapping is to help me out to see while i'm Porting the Bowls and Chambers .

[steve cowan]

Kevin,
That photo is a 50 deg seat with 40 deg top cut 0.100" wide blended into chamber,
Larry gives excellent advice

Hi Steve.
That would be this picture?


20201214_114405.jpg


Pretty sure these are yours. Which heads?

Dart 165cc 1.94" - 1.5" valves
Out to 186 cc with a 62 cc chamber

[skinny z]

Kevin,
That photo is a 50 deg seat with 40 deg top cut 0.100" wide blended into chamber,
Larry gives excellent advice

Hi Steve.
That would be this picture?


20201214_114405.jpg


Pretty sure these are yours. Which heads?

Dart 165cc 1.94" - 1.5" valves
Out to 186 cc with a 62 cc chamber

Thanks Steve.

[skinny z]

Something very timely from Weingartner Racing.
At about the 5 minute mark he describes exactly the condition of my combustion chambers.

https://www.youtube.com/watch?v=iVR0BctDhjM

The general consensus of the crowd here aligns with his approach to correcting the problem as well.

Weingartner.jpg

Weingartner (Brodix IK200)

Mine.jpg

Mine (RHS Pro Torker)

Time to grind.

[408swinger]

I watched that video the other day .
I couldnt figure out if he was recommending to smmoth out the step on both the intake and exhaust or just the intake.
I have a set of heads that have about a .040 step on the exhaust seat and when I mentioned it to the porter he said to leave it alone .