Wednesday, March 9, 2011

Competition Heads. Part 1

These heads are going on a 110CI engine, using 1.990" intakes and 1.610" exhausts. Stock valve sizes are 1.800" and 1.570" respectively.
Pic1: I have already installed the bronze guides and reamed them to size, machined the counterbore for the new seats and installed them. The head to the left has the valve job cut.
Pic2: Shows that I rough out the port work around the guides before they are installed. This allows a nice finish/shape all the way tight to the guide.
Pic3: Cutting the VJ on the exhaust side. I am also setting the depth at the same time allowing for enough valve to valve clearance and correct installed height.
Pic4: This shows a completed VJ. This is very critical to the engines performance, if it is not correct the heads will never flow good air, and the engine will not make good power.
Pic5: This is the fixture I built to open the valves. I use this to check valve to valve clearance and to accurately open the valves on the flowbench.
Pic6: Shows the VtoV clearance. As the exhaust valve is closing the intake valve is opening. This particular engine has a TDC lift of .212" and .196", with .035" VtoV. If this clearance is not adequate the valves clip each other at first rotation, leaving you with junk.
Pic7: These heads are going on a engine with a 4" bore. Since the valves have been sunk to to gain VtoV the chamber is slightly shrouding them. This relief work gained over 10cfm on the intake side.
Pic8: Blending the chamber before polishing. Those valves are just there to protect the seats.
Stay tuned for Part 2!

1 comment:

BonerDonor said...

MAN O MAN! throwing the book o' tricks out there! don't let em have all the secrets now PAT!!