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3 angle valve seats
will121 - 24/11/11 at 07:44 PM

I recently brought a set of Neway valve seat cutter and cut 3 angle valve seats dont know what difference it will really make to flow but hopefully make lapping in of the valves easier



daviep - 24/11/11 at 08:06 PM

That looks very nice job, neway cutters are excellent in my opinion.

If you've ground the valves then lapping will take less tha 5mins a valve.

Davie

snapper - 24/11/11 at 08:10 PM

The 3 angle seat is worth more and more as you increase power.
I would blend the chamber floor to the first angle, the one that is the top cut.
Perhaps penny on a stick waisted stem valves would add some more bhp.
It's all about the little improvements that add up to the big difference.

Bare - 24/11/11 at 09:39 PM

Ermm. those seats look to be rough, almost as if the cutters were Bouncing .
Best see to that or it will all be for nowt

will121 - 24/11/11 at 09:55 PM

quote:
Originally posted by Bare
Ermm. those seats look to be rough, almost as if the cutters were Bouncing .
Best see to that or it will all be for nowt



As you say the 60deg cutter does not give as good a finish as the 30 and 45, as you can see from the cutters they have different blades, i might just swap them round to see if gives a better finish but in reality may visually apear rougher but not sure it will effect actual flow

snapper - 25/11/11 at 07:34 AM

As you know the valve only seats on the 45 deg cut the rest is for flow.
Also the 45 deg cut looks very wide, I believe you only need 1.5 mm

[Edited on 25/11/11 by snapper]

ncoll - 25/11/11 at 08:52 PM

hi will121
if the seats have chatter marks on the 45 degree cut, lap in with fine grinding paste, then check with engineers blue. If the chatter marks are too deep, you will need to practice on a spare head to improve your technique, Then give the seats a light cut and lap in again. With the valves, forget about the penny on a stick, that idea went out in the 1960's. Get the 45 degree seat refaced, then get them to cut a 30 degree backcut to get the seat width the same as in the head. Instead of trying to blend in the top cut, buy a 10 or a 15 degree cutter and lightly blend in with that.




ncoll

rusty nuts - 25/11/11 at 10:06 PM

You may find using cutting lubricant and varying the pressure on the seat cutter may help give a smoother finish, as said practice on a spare head if you can

will121 - 4/12/11 at 02:58 PM

Thanks for the info, Ive swapped the cutter blades around as you can see the 60deg cutter had a different blade and was the only cut that had a poor finish, now recut and looks fine and seats all about 1.5mm wide, looked at back cutting valves but that's not cheap when you times by 16