I have had several people ask about what I do to equalize the combustion chambers when I resurface a cylinder head so I thought I would post it here.
I found that it was pretty common to find cylinder heads with uneven chamber sizes when I checked them with a burrette. What I found was often the measurement from the gasket surface to the squish band varied from one chamber to the other and when I would machine the surface to make the squish band depth the same- then the chambers would be pretty close to the same volume.
Here is what I started doing several years back whenever I resurfaced a cylinder head.
First I put two identical machined rings in the chamber. They set in the recess against the squish area.
Then I bolt the head to the jig with the rings supporting the head and surface the three mounting pads on top of the head.
Now the three mounting pads are parallel with the squish band so I install studs to bolt the head to the jig.
Now when I machine the gasket surface I know it will be parallel with the squish band
Now the measurement from the gasket surface to the squish band is equal all the way around.
Now I know that the volume of the chambers is pretty close from one side to the other.
Granted it is not as accurate as CCing a head which I would still do on a maximum effort race motor but it is good enough for a performance street motor and a lot cheaper. Jim
I found that it was pretty common to find cylinder heads with uneven chamber sizes when I checked them with a burrette. What I found was often the measurement from the gasket surface to the squish band varied from one chamber to the other and when I would machine the surface to make the squish band depth the same- then the chambers would be pretty close to the same volume.
Here is what I started doing several years back whenever I resurfaced a cylinder head.
First I put two identical machined rings in the chamber. They set in the recess against the squish area.
Then I bolt the head to the jig with the rings supporting the head and surface the three mounting pads on top of the head.
Now the three mounting pads are parallel with the squish band so I install studs to bolt the head to the jig.
Now when I machine the gasket surface I know it will be parallel with the squish band
Now the measurement from the gasket surface to the squish band is equal all the way around.
Now I know that the volume of the chambers is pretty close from one side to the other.
Granted it is not as accurate as CCing a head which I would still do on a maximum effort race motor but it is good enough for a performance street motor and a lot cheaper. Jim
