How to PORT and POLISH

[Torchd]

I bought a rebuilt head for the 1.9 AAZ which i havn't installed so far....

It is assembled and i'd like to port and polish it before the install..

How do i port and polish?? and what things will i need for the job?  will i have to get new oil seals or anything that cannot be reinstalled once removed?

Thanks!!

[g-spec]

The way I did the head on my car is gasket matched. which means that you take the intake and exhaust gasket place it one the head and mark a circle on the inside of the gasket. Then I removed all extra material and smoothed it all the way to the valve seat. I also removed all the rough surfaces in the ports. The intake ports I left rougher...and the exhaust I polished smooth.
You will need some kind of rotary tool with all kinds of aluminum cutting and sanding bits. You will also need a valve spring compressor.

I hope that helps a little.
Cheers, Michal

[VW_Commuter]

Follow this google link and you will find many hits on how to port and polish a head.

[79rabbit4dr]

I always thought about using one of those cylinder honing ball things... if you could find a small enough one... i think that would work perfectly!

This is what I'm talking about, there's probably better articles/pictures, but this gives you an idea:
http://www.mrotoday.com/mro/archives/Uptime/08JJ_FlexibleCylinderHoning.htm

[chrisrandle1]

Has anyone done the port and polish by its self, meaning no other mods at the same time.  I was wondering what kind of gains I can expect from porting and polishing.

[hatemi]

One tip. Dont port match the exhaust. Or if you want to then fill the exhaust manifold and port that but dont make the exhaust exit any larger than it already is. Youll only kill the flow with that. And the exhaust gasket hole is actually larger than the hole in the manifold so there woldnt even be any reason to use it as the model. You can however make the exhaust port alot larger inside the head and around the valve stem.

[Pat Dolan]

Has anyone done the port and polish by its self, meaning no other mods at the same time.  I was wondering what kind of gains I can expect from porting and polishing.

WWAAYYY back when A2 were current, we bought an NA car that had been butchered by an idiot shop, and put it back together.  It was otherwise dead stock, except for the port job.  Performance was almost TD level.  I wanted to put a nice exhaust system behind it, but it sold too quickly (and boy did I ever get a lot of tickets in it!).

[Torchd]

Hayemi..... can you please clarify??  i didnt quite get you!

[hatemi]

If you make the exit of the exhaust port as large as the gascet is then its larger than the hole in the exhaust manifold. And by making it larger you slow the gas velocity thus making the turbo spool up later and work more ineficently. And the restriction in the port is behind the seat and around the valvestem anyway so no point in touching that area. My previos TDI head was practically untuched around the gascket areas but made 100% better where it counts.

[Torchd]

So u mean i shud't port the exhausts exits in the head?

[hatemi]

Yes. You will only kill the velocity of the gas and you dont want to do that.

[vanagonturbo]

Umm, if you port match the manifold too, then you have a result of great overall gains. I understand what you are saying about the gasses running into a wall if the exhaust manifold is not port matched too. I jsut spent 3 hours on my frankenmotor last weekend porting and polishing the exhaust ports. HUGE difference is area in the ports. Just gotta get the intakes done.

I do agree though, port matching the exhaust ports will not necessarily help. You need to do at least the inlet area of the exhaust manifold.

I wouldnt really worry about leaving the intake ports rough on a turbo engine, especially a Diesel. The turbulence caused by the roughness in the intake ports helps for better imulsification of the fuel when mixed with air. In the IDI application, the fuel is combusted in the swirl chamber so its not all that critical to have the intake ports rough.

[hatemi]

The only matching I would do would be done on the manifold side. You just DONT want to make the exhaust port on the head any larger than it already is. Smaler would propably work better!

If the exhaust manifold has a smaler hole than on the head(the gascket has alot larger hole than both) then by all means match it. If its larger then you either need to fill the gap by welding or just leave it be.

[tylernt]

You don't want to polish gasser intakes to a mirror finish because they need the turbulence to evenly mix the gasoline mist with the air. But on a diesel, polish that baby up. The swirl chamber gives you all the turbulence you need.

[DieselKraut]

I believe hatmi is correct about loss of velocity when porting the exhaust. But I would think a light polish on a TD would help. But on a N/A I think porting and polish w/ port matching would be the best. Since your not needing the exhaust press for the turbo.