hand finishing cnc'd heads ???

Reply Subscribe

Thread Tools

Search this Thread

Dec 16, 2006 | 01:51 AM

vader99

Thread Starter

TECH Enthusiast

iTrader: (4)

Joined: Dec 2001

Posts: 551

Likes: 4

From: Canada

hand finishing cnc'd heads ???

What all is done when someone hand-finishes a set of cnc'd cylinder heads?

Is it just taking out the cnc ridges or is it a little more extensive than that?

Dec 16, 2006 | 09:16 AM

GuitsBoy

TECH Senior Member

iTrader: (4)

Joined: Apr 2003

Posts: 6,249

Likes: 3

From: Long Island, NY

Quote:

Originally Posted by vader99

What all is done when someone hand-finishes a set of cnc'd cylinder heads?

Is it just taking out the cnc ridges or is it a little more extensive than that?

Usually, its just hand blending everything, and possibly getting any areas the CNC mill couldnt easily reach if it wasnt equipped with a tablet or rocker and the head was bolted flat to the table. Also, many times a CNC program will be set up conservatively to allow for any tiny variations in the casting. Hand finishing lets a person intelligently decide how close to take things.

Dec 16, 2006 | 09:18 AM

eamador11

TECH Resident

Joined: Jul 2005

Posts: 907

Likes: 1

From: NJ

Unless your an expert head porter, you can lose the chamber consistency real fast!

Dec 16, 2006 | 09:22 AM

GuitsBoy

TECH Senior Member

iTrader: (4)

Joined: Apr 2003

Posts: 6,249

Likes: 3

From: Long Island, NY

Quote:

Originally Posted by eamador11

Unless your an expert head porter, you can lose the chamber consistency real fast!

True, but i dont think youd want to take the grinder or cartridge roll to the chamber. I small wire wheel followed by a buff will start to shine the chambers up without taking off any material.

Dec 16, 2006 | 02:22 PM

vader99

Thread Starter

TECH Enthusiast

iTrader: (4)

Joined: Dec 2001

Posts: 551

Likes: 4

From: Canada

From what I have heard, you don't want to really touch the intake runners at all when hand-finishing, is that right? Smooth up the exhaust good, etc.

Dec 16, 2006 | 02:40 PM

GuitsBoy

TECH Senior Member

iTrader: (4)

Joined: Apr 2003

Posts: 6,249

Likes: 3

From: Long Island, NY

Quote:

Originally Posted by vader99

From what I have heard, you don't want to really touch the intake runners at all when hand-finishing, is that right? Smooth up the exhaust good, etc.

Well, you could touch them up with a sanding cartridge roll, maybe an 80 grit or so. Most say not to polish the intake runners though. The exhaust runner and combustion chamber can be polished to a mirror finish to keep the carbon from sticking and causing hotspots and to reflect heat back into the cylinder.

Reply Subscribe