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
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
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.
Cylinder Head 105 - Valve Job Basics
Valves not sealing? Valves not bent? This is how you fix that problem.
In this video I outline the basic valve job procedure. Cleaning the
valves, cleaning the seats, cleaning the combustion chamber and lapping the
valves in to make a better seal.
Here I cover the process start-to-finish. It's the same exact process for
pretty much all non-rotary combustion engines. It takes patience and
perseverance to do this job, but anyone can do it. Reference your service
manual for measurements and service limits. Everything else that's not in
your service manual is in this video.
I apologize for not having broken busted crap to work with in this video.
It's more beneficial to all of you when bad fortune falls on me because it
gets well documented, and many people watching these videos are looking for
answers. If you have bent valves, you will discover it quickly once you
chuck one up in the drill. You'll see the face of the valve wobble around
while it spins. You'll see evidence of this damage on the valve seat. If
it's bad, you may see damage on the valve guides in the form of cracks or
missing pieces where the valve guides protrude through the head ports.
Give all that stuff a good visual inspection. ...and if you doubt yourself,
never hesitate to get a second opinion or consult a machine shop. They
will have access to expensive tools that you wont find in your average
Volvo Engine head porting / port matching prep work !
Music : Mr oizo and Gaspard Augé "tricyle express"
Step two in the project :
Gasket matching is a good way to improve the flow in your head (engine
heads only) and to avoid the bad turbulences where they are not supposed to
be : between parts.
It's the first step in your porting job that you should think about ,and do
with your brain and hands.
The castings patterns are often quite "bad quality" (or i should say the
consequence of the application of a mass production process ) and it's the
way to start this kind of job.
MGB Cylinder Head Skim
Anthony at CK Motor engineers in High Wycombe skims the head of our Project
A previous reconditioner had skimmed the head and block out of true, so one
side of each was higher than the other. Anthony corrected this on the CKM
lathe by skillfully setting the lathe bed up after numerous checks and