For the next step, Tom used this cutter to unshroud the valves. Unshrouding involves cutting back the combustion chamber wall so it does not interfere with flow as the valve begins to open. Most head guys use a cutter and die grinder to grind the chamber back by hand. To speed this process and to make the cuts all consistent, Tom uses this cutter instead, cool!
Tom adjusts the depth of the cut before it’s done. The cut goes all the way out to the fire ring of the head gasket to help flow.
|The Serdi makes the cut.|
|Once again a dial indcator is used to make sure each cut is consistent.|
The unshrouded valve pocket is on the left. Look at the top cut in the chamber, nice and consistent. In the next step Tom used a rounded cutter and cut the radius for his famous radius valve job. Tom is very secretive on how he does this and what sort of radius he uses so we didn’t show it. Most head guys do a three angle or more valve job so the air can have a nice smooth approach to the valve seat and the exhaust can have an unobstructed exit. Tom’s valve jobs have a smooth sweeping and gentle radius leading to the seat that plunges deeply into the valve bowl, no angled cuts here. Tom has found that his method flows better than any other. No wonder he keeps exactly how he does this secret. Look at the machined radius on the seat on the left. You can see how the cut extends past the seat and into the bowl itself. It opens up the seat and gets the bowl ready for hand blending all in one cut! Good performance, fast completion and reasonable price. Tom will get your stuff done!