292 Turbo Head Flow Tests

[vortecpro]

Larry

Thanks for the excellent information! This .020-.030 cut you post about are talking about below the 60 or 75, and what angle do you use?

[maxracesoftware]

Larry

Thanks for the excellent information! This .020-.030 cut you post about are talking about below the 60 or 75, and what angle do you use?

that small ridge Angle looked like 85deg or 90deg Angle ( hard to measure angle exactly )
and the Ridge Angle is more pronounced all around the beginning of the Short Turn Curve
its not always all the way around the circumference of the Valve Job
its more very much defined from 10:00 O'Clock -to- 2:00 O'Clock positions
looking at the short turn side towards the Intake Port Entry /Gasket .

i used a 0.100" wide x 90deg Angle then a lower what would be hand ground -15deg or a 105deg bottom angle narrowing
only from 10:00 O'Clock -to- 2:00 O'Clock positions, so it ends up being only 0.020" or 0.030" width from 10:00 O'Clock -to- 2:00 O'Clock positions
and ends up being around .080 or so all the rest of the way around .

i created 3 aluminum templates :
10deg , 15deg , and 20deg
which are really = 100deg,105deg,110deg(20/110deg lost a little Flow, 15/105deg=was best )

the 15deg or 105deg is the last bottom cut angle under the 90deg angle and is hand ground
to the template , then the actual Short Turn Curve starts there .... this Hand-ground Angle sets the little Ridge-Angle width
only there between 10:00 O'Clock -to- 2:00 O'Clock positions

[maxracesoftware]

15deg=Best
10deg=2nd best
20deg=worse , don't use

i tried the 10deg/100deg Angle first
next refined the template look for the 15deg/105deg Angle so i could hold it better/easier

20deg/110deg template just about hurt Flow CFM everywhere in the Flow Curve

template range is from about 1.880 to 2.600 Intake Valve OD

BottomAngleTemplates.jpg

[vortecpro]

Larry

Thanks for taking the time to explain all this, its much appreciated! Who's wheel dresser do you use?

[maxracesoftware]

Larry

Thanks for taking the time to explain all this, its much appreciated! Who's wheel dresser do you use?

Who's wheel dresser do you use?

i don't quite understand this question ???
if you mean dressing Seat Grinding Stones ? i use KwikWay Dresser ,
but i hardly use any Stones anymore , i just use Vertical Mill + Goodson 3D system

if you mean Valve Grinding Stones ... i use KwikWay Valve Grinder diamond dresser
the Stones i use are Goodson

if you mean dressing Porting Stones ?? i don't ever use them , i just use Carbide Burrs + Sanding Rolls

[vortecpro]

Dresser for the seat grinding stones, is what I was asking about. Thanks Mark

[Elroy]

Maxrace, do you recall what the final throat diameters were on the pictured 292 heads? Maybe you stated but i missed it.

[maxracesoftware]

Dresser for the seat grinding stones, is what I was asking about. Thanks Mark

i still have a large variety of Stones from KwikWay and newer ones from Goodson,
and have a bunch of KwikWay Electric Grinders + 1 KwikWay Air Grinder that works the best overall !

i don't do any Valve Jobs with any Seat grinding stones anymore .... i just do all Valve Jobs on Vertical Mill w/Goodson 3D tooling
i robbed the Rollover Head Fixture top part off my Peterson Seat and Guide Machine and bolted it down on the Vertical Mill table
that makes it a pretty quick setup , so no real need to use Stones anymore ,
i need the "accuracy" of Goodson 3D , way better than Valve Job with Stones !

Goodson has a great Valve Grinder Stone Wheel ,
i use that same Stone on all types of Valve materials/alloys
and it works great on Titanium Valves too , can get a mirror or close to mirror finish .

i've changed my Diamond dresser angle a few degrees from OEM
to help get the better finish + use the original Sunnen Block Honing Oil + Varsol mix

by Elroy » Tue Feb 01, 2022 7:40 am
Maxrace, do you recall what the final throat diameters were on the pictured 292 heads? Maybe you stated but i missed it.

its a nice warm Day here ... i'll go measure the Throat diameters and Post that info later on today

[maxracesoftware]

Maxrace, do you recall what the final throat diameters were on the pictured 292 heads? Maybe you stated but i missed it.

for old Benoit C/ED #292 Turbo Heads have new 2.055/1.600 valves with new 45deg Valve Job

Intake Throat = 0.9173% just under bottom cut ,
however , the Throat tapers down from 1.885"ID to 1.711"ID just above bronze liner valve guide center
the Throat is tapered downward only on the exhaust side , and drops straight down on the Cylinder wall side

Exhaust Throat = 0.885% 1.416"ID no tapers , just straight down Bowl , enlarging afterwards

---------------------------------------------------------------------------

for the other #292 Turbo Heads , they have 2.080/1.600 combo with new 50deg Valve Job

Intake Throat = 0.8942% just under bottom cut ,
however , the Throat tapers down from 1.860"ID to 1.700"ID just above bronze liner valve guide center
the Throat is tapered downward only on the exhaust side , and drops straight down on the Cylinder wall side

Exhaust Throat = 0.9094% 1.455"ID no tapers , just straight down Bowl , enlarging afterwards

=================================================

i use the Goodson GV-251 White colored Stone 5.000" OD wheel
in my KwikWay Valve Grinder

i use this GV-251 for all Valve materials / alloys

[MELWAY]

Maxrace, do you recall what the final throat diameters were on the pictured 292 heads? Maybe you stated but i missed it.

for old Benoit C/ED #292 Turbo Heads have new 2.055/1.600 valves with new 45deg Valve Job

Intake Throat = 0.9173% just under bottom cut ,
however , the Throat tapers down from 1.885"ID to 1.711"ID just above bronze liner valve guide center
the Throat is tapered downward only on the exhaust side , and drops straight down on the Cylinder wall side

Exhaust Throat = 0.885% 1.416"ID no tapers , just straight down Bowl , enlarging afterwards

---------------------------------------------------------------------------

for the other #292 Turbo Heads , they have 2.080/1.600 combo with new 50deg Valve Job

Intake Throat = 0.8942% just under bottom cut ,
however , the Throat tapers down from 1.860"ID to 1.700"ID just above bronze liner valve guide center
the Throat is tapered downward only on the exhaust side , and drops straight down on the Cylinder wall side

Exhaust Throat = 0.9094% 1.455"ID no tapers , just straight down Bowl , enlarging afterwards

=================================================

i use the Goodson GV-251 White colored Stone 5.000" OD wheel
in my KwikWay Valve Grinder

i use this GV-251 for all Valve materials / alloys

Larry
Is the radical taper of throat in intake from 1.860” down to 1.700” by design to help bias turn the air into cylinder
Or is it because of limitations due to water jackets?

[maxracesoftware]

Maxrace, do you recall what the final throat diameters were on the pictured 292 heads? Maybe you stated but i missed it.

for old Benoit C/ED #292 Turbo Heads have new 2.055/1.600 valves with new 45deg Valve Job

Intake Throat = 0.9173% just under bottom cut ,
however , the Throat tapers down from 1.885"ID to 1.711"ID just above bronze liner valve guide center
the Throat is tapered downward only on the exhaust side , and drops straight down on the Cylinder wall side

Exhaust Throat = 0.885% 1.416"ID no tapers , just straight down Bowl , enlarging afterwards

---------------------------------------------------------------------------

for the other #292 Turbo Heads , they have 2.080/1.600 combo with new 50deg Valve Job

Intake Throat = 0.8942% just under bottom cut ,
however , the Throat tapers down from 1.860"ID to 1.700"ID just above bronze liner valve guide center
the Throat is tapered downward only on the exhaust side , and drops straight down on the Cylinder wall side

Exhaust Throat = 0.9094% 1.455"ID no tapers , just straight down Bowl , enlarging afterwards

=================================================

i use the Goodson GV-251 White colored Stone 5.000" OD wheel
in my KwikWay Valve Grinder

i use this GV-251 for all Valve materials / alloys

Larry
Is the radical taper of throat in intake from 1.860” down to 1.700” by design to help bias turn the air into cylinder
Or is it because of limitations due to water jackets?

its only because there's a waterjacket in that location in the bridge between the Intake and Exhaust Valves
i don't want to take a chance of breaking thru by using a 70deg or 75deg last bottom Cut , neither do i want to use a 90deg Bowl cutter,
instead i'd rather just Hand Port blend in Bowl area on the exhaust side of the Intake Bowl,
and i'll maxout the opposite wall on the Cylinder Wall side

i just do a 39/45seat/60 Valve Job ... then Hand Port / Blend into Bowl areas

only on most all aluminum Heads do i use 39/45seat/60/75/90 degree Cuts

[Fatman]

15deg=Best
10deg=2nd best
20deg=worse , don't use

i tried the 10deg/100deg Angle first
next refined the template look for the 15deg/105deg Angle so i could hold it better/easier

20deg/110deg template just about hurt Flow CFM everywhere in the Flow Curve

template range is from about 1.880 to 2.600 Intake Valve OD

BottomAngleTemplates.jpg

Will you try either side of 15 deg to see if they are better? eg 14 and 16? If a 1 deg change is too difficult, maybe 13 and 17?

[maxracesoftware]

by Fatman » Wed Feb 02, 2022 7:00 pm
Will you try either side of 15 deg to see if they are better? eg 14 and 16?
If a 1 deg change is too difficult, maybe 13 and 17?

if i get another Head to test on , i'll test more Angles

just for clarity , more Info :
that Template is only for around a 0.080" to 0.100" wide hand ground Angle
then at that point , the Short Turn Curve starts -to- the Floor's Apex Height
... Purple colored width = 0.080" to 0.100" wide Template Angle like a 15deg/105deg Hand Ported Angle
... Green colored line = Short Turn Curve example

BottomAngleTemplatesCurve.jpg

[Fatman]

15deg=Best
10deg=2nd best
20deg=worse , don't use

i tried the 10deg/100deg Angle first
next refined the template look for the 15deg/105deg Angle so i could hold it better/easier

20deg/110deg template just about hurt Flow CFM everywhere in the Flow Curve

template range is from about 1.880 to 2.600 Intake Valve OD

BottomAngleTemplates.jpg

Was this testing done on the 292 turbo head or something else?

[maxracesoftware]

by Fatman » Fri Feb 04, 2022 7:27 pm

Was this testing done on the 292 turbo head or something else?

not on these #292 Heads in this Thread .

some of the latest tests were with :
Chevy SBC 18deg
Brodix SBC Track 1
ProFiler_Raylar_8.1_BBC
bunch more

What's "pretty sad" on my part :
i did something like 105deg very bottom cut + clay buildup in a sort of "D-shape" only above the 105deg cut -to- the Bottom of 60deg Angle
on a sectioned 1 Cylinder piece of a #292 Turbo Head around 1978 to 1981, that i kept in a Freezer everytime i finished doing test on it
so to keep the modeling clay hard not to disturb its shape... picked up the Flow CFM everywhere
made some of the highest CFM numbers for a Turbo Head i've ever flow tested since ,
but i can't remember ever using it on a Customer's Heads , because it was way too critical to duplicate the shape
and the Intake Seat area had to have enough material to shape on the Short Turn Curve side .