Sorry for the dumb question but I don't understand all the fuss about 3-angle jobs.
According to Honda shop manual for B16A1 (EDM) the valve seat has a 3-angle jobs standard from the factory (30, 45, 60).

When people advise to get a 3-angle job for more flow what does that actually mean? Reconditioning of the valve seat (standard angles), different more high-flowing angles or have I totally misunderstood the whole thing?

Would really appreciate if someone could shed some light on this issue.

 

The term 3 angle is a very generic term like say "3 piece suit".

Angles, length of angles and where they are relative to the valve is critical.

The stock VJ is pretty good for low lift cams such as stock cams.

 

Thanks a lot!

I'm still a little confused though. Do many tuners/engine builders use any other actual valve seat angles than 45 (in Honda tuning heaven)? If not I don't understand why so many uses 3-angle and not 4-5 angles. I mean a 3-angle with an actual seat angle of 45 will be very limited. I guess 40-45-70 is a good compromise but why not go 4-angle 40-45-67-82 or even 5-angle?

The reason I ask is because here in Sweden the only performance shops available are specialized in muscle cars or turbo and I don't trust them with high-tech NA Honda engines. Thats why you have to do everything here by yourself or assure that the "engine tuners" do it right. If I had a Volvo or V8 I could just drop my stuff off at any neighbour, farm, bum, dog and get it done but building an NA Honda isn't that easy in Sweden.

Appreciate all the help I get from all you Honda tuning Gods in Honda tuning heaven.

 

Depends, my valve job guy does mostly V8 but is also good at BMW and motorcylce 4 valve heads.

Alot of times the extra angles doesn't direct the air as one long angle would. It depends on the interaction of the valve face and seat angles. On long throat ports using high lift cams some heads have 50 degree seats.

Usually if the shop has Serdi or Newn machine they prolly can get something good.