will121
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| posted on 24/11/11 at 07:44 PM |
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3 angle valve seats
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
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daviep
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| posted on 24/11/11 at 08:06 PM |
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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
“A truly great library contains something in it to offend everyone.”
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snapper
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| posted on 24/11/11 at 08:10 PM |
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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.
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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Bare
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| posted on 24/11/11 at 09:39 PM |
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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
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will121
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| posted on 24/11/11 at 09:55 PM |
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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
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snapper
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| posted on 25/11/11 at 07:34 AM |
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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]
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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ncoll
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| posted on 25/11/11 at 08:52 PM |
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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
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rusty nuts
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| posted on 25/11/11 at 10:06 PM |
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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
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will121
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| posted on 4/12/11 at 02:58 PM |
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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
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