Chevy 193 Swirl port Mission Impossible

[PRH]

The head I have here looks to be unmolested from the factory.
The OD of the 45 angle of the valve job measures 1.91”, and the OE valves I took out are 1.94”.

IMG_3394.jpeg

IMG_3395.jpeg

IMG_3396.jpeg

There are also differences in opinion on the claimed chamber volume……76 or 64.
This head, which still has the factory deck finish on it measured 65cc.

I would say this is at least a “medium duty” truck head, with its hardened exhaust seat insert and 3/8” stem exhaust valves.

[juuhanaa]

Could it be that there are two sizes of chambers, which possible explain the difference in flow numbers?

And Charlie; Have you tried a different size bore adapter to see if it is sensitive like the chamber might be?



-juhana

[Tuner]

quote="Bob Hollinshead" post_id=535837 time=1422449129 user_id=6637
Wed Jan 28, 2015 4:45 am
From another thread on swirl ports: All I did was knock the casting flash off the intake, reworked the intake bowl area and swirl ramp (swirl ram is still in place), then reworked the exhaust like you would any small block head. I also unshrouded and opened up the chambers slightly around the intake and exhaust valves. The heads still exhibit very strong swirl. While cleaning them I sprayed water into the intake port and recieved an unexpected shower. The swirl port literally threw water out in about a 6' diameter area. The heads were flow benched at 28 in/h20 just like any other head.

Notice how much better the exhaust flow is than the intake considering the intake is through a 1.94" valve and the exhaust a 1.5"



Valve Lift------Intake Flow---------Exhaust Flow
.050--------------35.6----------------------31.0
.100--------------72.4----------------------60.5
.150-------------105.8---------------------87.3
.200-------------133.4--------------------124.2
.250-------------154.1--------------------147.3
.300-------------180.6--------------------171.5
.350-------------195.5--------------------184.7
.400-------------209.3--------------------196.3
.450-------------217.4--------------------203.7
.500-------------224.3--------------------215.6

So how do you cam a motor when the intake flows just about the same as the exhaust? And what's the power capability of the head? 300hp?

[HQM383]

quote="Bob Hollinshead" post_id=535837 time=1422449129 user_id=6637
Wed Jan 28, 2015 4:45 am
From another thread on swirl ports: All I did was knock the casting flash off the intake, reworked the intake bowl area and swirl ramp (swirl ram is still in place), then reworked the exhaust like you would any small block head. I also unshrouded and opened up the chambers slightly around the intake and exhaust valves. The heads still exhibit very strong swirl. While cleaning them I sprayed water into the intake port and recieved an unexpected shower. The swirl port literally threw water out in about a 6' diameter area. The heads were flow benched at 28 in/h20 just like any other head.

Notice how much better the exhaust flow is than the intake considering the intake is through a 1.94" valve and the exhaust a 1.5"



Valve Lift------Intake Flow---------Exhaust Flow
.050--------------35.6----------------------31.0
.100--------------72.4----------------------60.5
.150-------------105.8---------------------87.3
.200-------------133.4--------------------124.2
.250-------------154.1--------------------147.3
.300-------------180.6--------------------171.5
.350-------------195.5--------------------184.7
.400-------------209.3--------------------196.3
.450-------------217.4--------------------203.7
.500-------------224.3--------------------215.6

So how do you cam a motor when the intake flows just about the same as the exhaust? And what's the power capability of the head? 300hp?

Sim using above head flow:

3026 Iterator test, testing cam events for peak HP
355ci (4.030" x 3.480")
Compression 10:1 using 93 octane pump gas
high flow dual plane manifold
1.650" headers
Cam specs: int 265* @ .050" exh 250* @ .050". Lift .420" lobes with 1.6 int and 1.5 exh rockers with lash = int .652" exh .608. LSA 118*installed 4* advanced.
Peak HP 525hp @ 6500rpm

As above but testing for peak torque
Cam specs: int 235* @ .050" exh 237* @ .050". Lift .380" lobes with 1.6 rockers and lash = .586 int & exh. LSA 104 advanced 3*
Peak tq 480ft/lb @ 4000rpm

These would be roller due to acceleration rates and lift. They could be refined further but gives an indication where cam would be headed depending on goal of peak tq or peak hp

[Tom68]

quote="Bob Hollinshead" post_id=535837 time=1422449129 user_id=6637
Wed Jan 28, 2015 4:45 am
From another thread on swirl ports: All I did was knock the casting flash off the intake, reworked the intake bowl area and swirl ramp (swirl ram is still in place), then reworked the exhaust like you would any small block head. I also unshrouded and opened up the chambers slightly around the intake and exhaust valves. The heads still exhibit very strong swirl. While cleaning them I sprayed water into the intake port and recieved an unexpected shower. The swirl port literally threw water out in about a 6' diameter area. The heads were flow benched at 28 in/h20 just like any other head.

Notice how much better the exhaust flow is than the intake considering the intake is through a 1.94" valve and the exhaust a 1.5"



Valve Lift------Intake Flow---------Exhaust Flow
.050--------------35.6----------------------31.0
.100--------------72.4----------------------60.5
.150-------------105.8---------------------87.3
.200-------------133.4--------------------124.2
.250-------------154.1--------------------147.3
.300-------------180.6--------------------171.5
.350-------------195.5--------------------184.7
.400-------------209.3--------------------196.3
.450-------------217.4--------------------203.7
.500-------------224.3--------------------215.6

So how do you cam a motor when the intake flows just about the same as the exhaust? And what's the power capability of the head? 300hp?

Sim using above head flow:

3026 Iterator test, testing cam events for peak HP
355ci (4.030" x 3.480")
Compression 10:1 using 93 octane pump gas
high flow dual plane manifold
1.650" headers
Cam specs: int 265* @ .050" exh 250* @ .050". Lift .420" lobes with 1.6 int and 1.5 exh rockers with lash = int .652" exh .608. LSA 118*installed 4* advanced.
Peak HP 525hp @ 6500rpm

As above but testing for peak torque
Cam specs: int 235* @ .050" exh 237* @ .050". Lift .380" lobes with 1.6 rockers and lash = .586 int & exh. LSA 104 advanced 3*
Peak tq 480ft/lb @ 4000rpm

These would be roller due to acceleration rates and lift. They could be refined further but gives an indication where cam would be headed depending on goal of peak tq or peak hp

What's the peak torque with the 265 cam ?

[HQM383]

quote="Bob Hollinshead" post_id=535837 time=1422449129 user_id=6637
Wed Jan 28, 2015 4:45 am
From another thread on swirl ports: All I did was knock the casting flash off the intake, reworked the intake bowl area and swirl ramp (swirl ram is still in place), then reworked the exhaust like you would any small block head. I also unshrouded and opened up the chambers slightly around the intake and exhaust valves. The heads still exhibit very strong swirl. While cleaning them I sprayed water into the intake port and recieved an unexpected shower. The swirl port literally threw water out in about a 6' diameter area. The heads were flow benched at 28 in/h20 just like any other head.

Notice how much better the exhaust flow is than the intake considering the intake is through a 1.94" valve and the exhaust a 1.5"



Valve Lift------Intake Flow---------Exhaust Flow
.050--------------35.6----------------------31.0
.100--------------72.4----------------------60.5
.150-------------105.8---------------------87.3
.200-------------133.4--------------------124.2
.250-------------154.1--------------------147.3
.300-------------180.6--------------------171.5
.350-------------195.5--------------------184.7
.400-------------209.3--------------------196.3
.450-------------217.4--------------------203.7
.500-------------224.3--------------------215.6

So how do you cam a motor when the intake flows just about the same as the exhaust? And what's the power capability of the head? 300hp?

Sim using above head flow:

3026 Iterator test, testing cam events for peak HP
355ci (4.030" x 3.480")
Compression 10:1 using 93 octane pump gas
high flow dual plane manifold
1.650" headers
Cam specs: int 265* @ .050" exh 250* @ .050". Lift .420" lobes with 1.6 int and 1.5 exh rockers with lash = int .652" exh .608. LSA 118*installed 4* advanced.
Peak HP 525hp @ 6500rpm

As above but testing for peak torque
Cam specs: int 235* @ .050" exh 237* @ .050". Lift .380" lobes with 1.6 rockers and lash = .586 int & exh. LSA 104 advanced 3*
Peak tq 480ft/lb @ 4000rpm

These would be roller due to acceleration rates and lift. They could be refined further but gives an indication where cam would be headed depending on goal of peak tq or peak hp

What's the peak torque with the 265 cam ?

440ft/lb @ 5500rpm

[Carnut1]

Could it be that there are two sizes of chambers, which possible explain the difference in flow numbers?

And Charlie; Have you tried a different size bore adapter to see if it is sensitive like the chamber might be?



-juhana

I have I will be using a 400 block so I am set to 400 gasket size. It was a few cfm over 350 gasket size. Thanks

[Carnut1]

20231217_191935.jpg

Could it be that there are two sizes of chambers, which possible explain the difference in flow numbers?

And Charlie; Have you tried a different size bore adapter to see if it is sensitive like the chamber might be?



-juhana

I have I will be using a 400 block so I am set to 400 gasket size. It was a few cfm over 350 gasket size. Thanks

Where this is headed. Thanks

[juuhanaa]

20231217_191935.jpg

Could it be that there are two sizes of chambers, which possible explain the difference in flow numbers?

And Charlie; Have you tried a different size bore adapter to see if it is sensitive like the chamber might be?



-juhana

I have I will be using a 400 block so I am set to 400 gasket size. It was a few cfm over 350 gasket size. Thanks

Where this is headed. Thanks

Your work truck, of course



-juhana

[Carnut1]

I have been thinking of a set for the old work truck...

[F-BIRD'88]

Carnut: Will you be flow testing your heads before you start port modifications to get a baseline?

[Carnut1]

Carnut: Will you be flow testing your heads before you start port modifications to get a baseline?

Yes, first video of series 1.94/1.5 combo 175 / 125 cfm more or less. Pretty bad!

[juuhanaa]

How much the swirl would change if the manifold runners were like in this Edelbrock Scorpion2 ?

6050077615.jpg

-juhana

[Carnut1]

Alot.

[Carnut1]

20231219_152204.jpg

Intake flows and air speeds as of now. Not a small port 228cc with 100cc bowl!