Cylinder Head 201 - Radius Cut Valve Job

This video covers the complete valve job process that your machinist might perform. If the 100 series videos didn't help you identify and correct a problem with your cylinder head, then this is the next step. This video is brought to you with permission from my machinist in full 1080HD, and covers cleaning up the head inside and out, preparation and setting up a radius cutter, cutting all 16 valve seats, valve grinding, and spans 3.5 hours of actual work in under 30 minutes. There's nothing like this anywhere else on YouTube.

THANK YOU BALLOS PRECISION MACHINE. Thank you for the professional explanation and execution of a job excellently-done, and un-precedented access to your facilities.

A valve job is done by re-grinding or replacing valves, and then having new seats cut to match the faces of the valves you're using. There are several different machines that might be utilized to achieve this result, but the process is the same no matter how it's done. There are seat cutters that utilize cutting stones. There are valve seat cutters with 3 separate angles installed 120° out-of-phase, and there are single cutters with all 3 angles (radius cutter) that cut with one blade in one pass. The machine demonstrated here is a Sunnen VGS-20 Radius Cutter. This machine (now out of production) produces a gradual curved seat that's superior to the shape of a traditional 3-angle seat. While a radius cutter does contain the 30, 45 and 60 degree angles, it does so without leaving any sharp edges between their faces.

My valve selection includes Supertech 1mm oversized nitride-coated stainless steel undercut and back-cut intake valves, and 1mm oversized Inconel back-cut exhaust valves. Inconel is a high-temperature alloy utilized in marine and forced-induction performance engines that can handle more abuse than steel can without melting. The other characteristics of the valves which are discussed typically yield bigger gains in airflow than simply using a bigger hole and a bigger valve.

Why I did this to a perfectly-good cylinder head:
I changed cams. Because the valves were previously recessed during another valve job 9 years ago, my valve installed height was increased and this raised the operating positions of my rocker arms. My new camshaft selection dictates using the stock valve install height. The only solutions to this valve install height problem are to either replace the valve seats, or install oversized valves. I opted for the latter.

Видео Cylinder Head 201 - Radius Cut Valve Job канала Jafromobile