Destroying Flatheads for Science - Will They Handle Big Boost?
- Thread starter Ziggster
- Start date
Ronnieroadster
Well-known member
Well I will say there's a whole lot more that needs to be determined than what this guy is talking!
One example there's the wrong way to gain valve clearance and what I consider the right way.
Since the valve seat is at an angle to the deck when valve clearance is needed you don't hog out the entire valve pocket that's the wrong way!
The correct way only area that needs to be modified is the top area of the pocket where the valve will actually touch upon full lift. To do this the head is placed in the mill so the deck surface is now at the same angle as the valve. Now using a radius edged end mill just the material needed for clearance along the top inner and side edge can be removed. Doing it this way will not reduce the strength of the valve pocket.
If someone is interested in the actual strength of the head it should be cut straight across the center of the dome. How thick is that area of the head?
On a supercharged Ford flathead engine the failure will take place in the dome area. Failures that happen will be related to a lean condition which will create so much heat a hole will burn into the center of the head or the center of the piston dome.
When it comes to actual boost numbers you need to understand the intake port flow acts like a water valve it can only flow so much. So a big boost number really only means the port may not be flowing as well as one would like.
As Tim wrote above we have run high boost up to 23 pounds BUT doing this was during our engine development. To develop a Ford flathead block that will survive for numerous 5 mile runs turning 6500 RPM at every shift point the boost levels needed are now under 20.
There's lots more than just the combustion chamber involved to be able to run over 200 MPH burning gasoline. Setting records with a 292 cubic inch Ford flathead V-8 block with three exhaust ports can be done our results show its possible. Our development has shown reliability is possible with a Ford flathead block one of our engine's has over 50 miles on it running over 200 MPH on every run. Its also set and reset records for a number of years.
WARNING YOUR RESULTS MAY VARY
Ronnieroadster
One example there's the wrong way to gain valve clearance and what I consider the right way.
Since the valve seat is at an angle to the deck when valve clearance is needed you don't hog out the entire valve pocket that's the wrong way!
The correct way only area that needs to be modified is the top area of the pocket where the valve will actually touch upon full lift. To do this the head is placed in the mill so the deck surface is now at the same angle as the valve. Now using a radius edged end mill just the material needed for clearance along the top inner and side edge can be removed. Doing it this way will not reduce the strength of the valve pocket.
If someone is interested in the actual strength of the head it should be cut straight across the center of the dome. How thick is that area of the head?
On a supercharged Ford flathead engine the failure will take place in the dome area. Failures that happen will be related to a lean condition which will create so much heat a hole will burn into the center of the head or the center of the piston dome.
When it comes to actual boost numbers you need to understand the intake port flow acts like a water valve it can only flow so much. So a big boost number really only means the port may not be flowing as well as one would like.
As Tim wrote above we have run high boost up to 23 pounds BUT doing this was during our engine development. To develop a Ford flathead block that will survive for numerous 5 mile runs turning 6500 RPM at every shift point the boost levels needed are now under 20.
There's lots more than just the combustion chamber involved to be able to run over 200 MPH burning gasoline. Setting records with a 292 cubic inch Ford flathead V-8 block with three exhaust ports can be done our results show its possible. Our development has shown reliability is possible with a Ford flathead block one of our engine's has over 50 miles on it running over 200 MPH on every run. Its also set and reset records for a number of years.
WARNING YOUR RESULTS MAY VARY
Ronnieroadster
