Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Port and Polish?

Since the SVT UIM I got has already been ported nad polished, I'm thinking maybe I should do the lowers and the heads too to match them... But I know it'll cost quite a bit of money to do the heads. So, my question would be - will I loose HP if I leave both the LIM and heads as is with the UIM ported and polished?

The SVT's UIM & heads are Extrude Honed. Big difference.

The LIM has no need for EH or polishing. It's machine bored aluminum.

Stock head ports could use some touching up (porting) but skip the polishing.

Don't forget all the port matching.

The thing is though, the SVT UIM I got has already been ported and polished. I just want to port the lower and the heads to match the larger bore on the UIM.

The SVT heads already have the extrude hone process applied. The 98 to just the secondary intakes, and the 99 and 00 to the primary and secondary intakes. I guess you could to the exhausts though.

It sounds like what you are describing is "port matching". In port matching, you match the ports of the heads to the ports of the manifold (and between the upper and lower intake manifold as well). This is usually done by using the gaskets as a template. Lay the gasket in place, and scribe the head or mainfold at the opening of the gasket. Then with a dye grinder gently open the port to match the gasket. It would be wise to study the topic a bit before you try it.

Yeah, I think I'm talking about port matching. The UIM I bought with the 3L engine has already been ported and polished so I won't be doing anything to them. I just want to know if I should do the same to the LIM and heads.

NOT Port & polished!!!

Extrude Honed!

I also mentioned port matching!

Please read my first post... :rolleyes:

BTW - the 3L UIM is also not P&P'd nor EH'd!

IIRC, he got a deal from Bill P including the SVT intakes and the 3 liter block, right?

Bill had done some after market work on these parts that would need to be finished on the heads to match the ports on the manifolds.

You may not want to gasket match the LIM to the UIM since the gasket holes are waaaaaaaay larger than the internal ports of the UIM, meaning you'd have larger ports in the LIM which will cause a reduction in air speed. Match the LIM to the UIM ports and you'll be better off. Port matching is different than gasket matching in this case...

Dude, it got extra port and polishing to the stock UIM. I know the stock one got extrude honed, but Bill P (yes, I got the engine and stuff from him) had it ported and polished when he was going to do the 3L on his Focus.

A couple observation I made while swapping in the SVT UIM last weekend:

1. First off, the SVT UIM is a completely different casting from the stock one, just FYI. It's not a modified stock one.

2. The TB side of the SVT one has a smoother interior wall....but on the exit side, the finish is sandpaper-like and is covered in overspray from the black powdercoat. It confuses me how or if extrude honing was done.

At first, I was actually saving the UIM for a future engine build, but when I had everything apart for cleaning, I noticed the SVT ports EXACTLY matched my stock LIM ports. The primaries on the stock UIM looked puny in comparison (27mm to be exact).

And yes, the UIM to LIM gaskets are big, 35 and 36mm, just adding numbers to what Brad said.

How did they ported & polished the UIM?

It's not possible. Not in the truest sense of the terms.

They could do it to the last few inches of each port, but not any deeper. Hence the reason for needing the EH process...

Also you do not want the sides of the manifold to be polished smooth.

Wayne - The EH process was done on a bare UIM. Then the manifold was powdercoated. Then the surfaces were machined.
This is why you can get powdercoating (sand paper) inside the ports (I had none personally) and the mating surfaces roll into the airflow of the ports. (I had that on every port!)