Head porting and polishing
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Junior User
Joined: Sep 2002
Posts: 67
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From: Puebla Mexico
Head porting and polishing
Hey guys
I have a spare set of heads that would like to use for practicing porting and polishing by my sellf.
I have no idea so far of how should this been done in order to do it right, does anybody can explainme the proper way for oding it? Is there any place on the net where to find instructions on how to do it?
Also whould like to know how does porting and polishing affects (positibelly and negatibelly) the performance on the engine? Whats the efect on porting and polishing? What the benefits are?
Thanks a lot for your help.
Regards
Ray
I have a spare set of heads that would like to use for practicing porting and polishing by my sellf.
I have no idea so far of how should this been done in order to do it right, does anybody can explainme the proper way for oding it? Is there any place on the net where to find instructions on how to do it?
Also whould like to know how does porting and polishing affects (positibelly and negatibelly) the performance on the engine? Whats the efect on porting and polishing? What the benefits are?
Thanks a lot for your help.
Regards
Ray
New User
Joined: Jan 2003
Posts: 13
Likes: 0
From: Greensboro,NC USA
Head porting and polishing
Just a few things from David Vizard's "How to Build Horsepower":
Porting: do not remove any material from bottom of the runners, open up and widen the tops only. Smooth transition from port to valve seat. He says you don't need to really polish the runners since the rougher surfaces will keep fuel from collecting on the port walls. Get a three-angle seat and valve job from machine shop.
Combustion Chamber: Don't remove much material so CR doesn't drop. polish the surfaces. Remove only sharp material that interrupts flow in the chamber.
Never tried it myself.
Porting: do not remove any material from bottom of the runners, open up and widen the tops only. Smooth transition from port to valve seat. He says you don't need to really polish the runners since the rougher surfaces will keep fuel from collecting on the port walls. Get a three-angle seat and valve job from machine shop.
Combustion Chamber: Don't remove much material so CR doesn't drop. polish the surfaces. Remove only sharp material that interrupts flow in the chamber.
Never tried it myself.
Senior User
Joined: Jun 2002
Posts: 423
Likes: 0
From: Oklahoma
Head porting and polishing
Porting and polishing simply removes restrictions in air flow through the motor; ie. the engine can breathe better. You can use FelPro gaskets, #1415 exhaust and #1250 intake, to establish port opening size. The main area of gain is smoothing bowls, tapering the guides and smoothing the valve seat to port junction. On the exhaust side, remove the Thermactor bump as well. Although polishing the intake port is generally considered a bad idea due to possible mixture separation, the exhaust port doesn't have that problem and benefits from polishing.
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fred_darrel
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
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Feb 7, 2003 06:14 PM
