Angle Mill vs. Flat Mill: Piston to valve question-->
Thread Starter
Racer
Joined: Aug 2001
Posts: 445
Likes: 2
From: Austin Texas
Angle Mill vs. Flat Mill: Piston to valve question-->
If you had a head with a 110cc chamber that had been flat milled to that volume and had no piston to valve interference, could you make a leap of faith and say that a head with the same 110cc chamber that had been ANGLE MILLED to that cc would also have NO piston to valve interference???
Thanks in advance to the gurus.
Bryan
Thanks in advance to the gurus.
Bryan
Melting Slicks
Joined: Apr 2000
Posts: 3,341
Likes: 6
Originally Posted by 300ZXTwinTurbo
...could you make a leap of faith...
Safety Car
Joined: Oct 2004
Posts: 3,924
Likes: 735
From: Youngstown Ohio
Originally Posted by 45ACP
No. Never. Either from experience, careful calculations or test fitting you must KNOW that there is no interference before lighting her off.
ANY milling yields less clearance......from knowledge or test fitting, be certain.
Thread Starter
Racer
Joined: Aug 2001
Posts: 445
Likes: 2
From: Austin Texas
No doubt I appreciate all of the words of caution in terms of checking / measuring; that is something that my machine shop will no doubt do.
I suppose the real information I was looking to gather had to do with how the valves sit relative to the piston and how that relationship changes when you choose to angle/flat mill a head.
In other words, which choice of milling would cause you to run into interference with a piston more readily?
Anyone have that answer?
Thanks.
Bryan
I suppose the real information I was looking to gather had to do with how the valves sit relative to the piston and how that relationship changes when you choose to angle/flat mill a head.
In other words, which choice of milling would cause you to run into interference with a piston more readily?
Anyone have that answer?
Thanks.
Bryan
Safety Car
Joined: Oct 2004
Posts: 3,924
Likes: 735
From: Youngstown Ohio
Originally Posted by 300ZXTwinTurbo
No doubt I appreciate all of the words of caution in terms of checking / measuring; that is something that my machine shop will no doubt do.
I suppose the real information I was looking to gather had to do with how the valves sit relative to the piston and how that relationship changes when you choose to angle/flat mill a head.
In other words, which choice of milling would cause you to run into interference with a piston more readily?
Anyone have that answer?
Thanks.
Bryan
I suppose the real information I was looking to gather had to do with how the valves sit relative to the piston and how that relationship changes when you choose to angle/flat mill a head.
In other words, which choice of milling would cause you to run into interference with a piston more readily?
Anyone have that answer?
Thanks.
Bryan
Racer
Joined: Jul 2005
Posts: 317
Likes: 0
From: PA
I know from experience with pistons at .240 dome (in bbc's) that when you start getting around .520" lift it's close and you start to check, if your using .100" domes or less you can get more without worry. Watch your valve springs... not enough pressure will send them into the piston at high rev's.
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Brett Foote
Team Owner
Joined: Sep 2003
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From: eville in
Originally Posted by 300ZXTwinTurbo
If you had a head with a 110cc chamber that had been flat milled to that volume and had no piston to valve interference, could you make a leap of faith and say that a head with the same 110cc chamber that had been ANGLE MILLED to that cc would also have NO piston to valve interference???
Thanks in advance to the gurus.
Bryan
Thanks in advance to the gurus.
Bryan
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Angle milling rolls the head over slights, It changes slightly the angle at which the valve strikes the piston, well we hope it doesn't hit but the angle changes so the chances of the upper corner stricking the piston are greater but it increases flow more then flat milling.
The intake becomes a problem and the head/intake surfaces need to be changed along with the head bolt holes.
Rolling the head over changes the hole through the head for the head bolts. Too much angle mill and the bolt holes need to be opened up.
Also the bolt holes need to be spot faced to straighten up the bolt hole for the head of the bolt to rest flat on the head.
The intake becomes a problem and the head/intake surfaces need to be changed along with the head bolt holes.
Rolling the head over changes the hole through the head for the head bolts. Too much angle mill and the bolt holes need to be opened up.
Also the bolt holes need to be spot faced to straighten up the bolt hole for the head of the bolt to rest flat on the head.
