Port matching

[mardak at cogeco.ca (Mark)]

Scourge wrote:
> So, while I've got the head off and manifoldness I was thinking some
> port matching(right term?) may be a good idea. I've been told it can
> make a huge difference. What's the best way to go about this? I was
> thinking: 1 bolt gasket to intake manifold and mark any areas that
> don't match up. 2 very carefully grind away excess material 3 bolt
> gasket to head and mark any material to be taken off. 4 again, very
> carefully grind away excess material.


Here's some things I'd recommend in your situation (not rebuilding the 
head at the time you're port matching it)

- Buying the Standard Abrasives Porting kit might be a bit overkill if 
you're just port matching.  I highly recommend it if you're doing a full 
P&P, but you can get by with a bunch of tapered (and not) rolls and some 
stones if you're just port matching...

- Stuff rags or whatever into the ports (leave 1"-2" open) to minimize 
the metal shavings/sand that can get deep into the ports

- Clean the mating surfaces of the head/manifolds with a file or 
sandpaper block until it's nice and shiny new metal (do it upside down 
if you're paranoid, so any sand/filings falls to the floor, and not into 
your head).

- Wipe off the surfaces with rag and thinners/brake cleaner.

- Use a Sharpie (black marker) to blacken the area around the port holes 
(or use machinist's blueing (?) (spray on, not the stuff in a tube)

- Put the studs in the head and place the gasket so it's centered nicely.

- Use a scribe to scribe a line of the outline of the gasket.  Do this 
on both the head and manifolds.

- Remove the metal to the scribed line. (a dremel will work, but it's a 
bit undersized for the job - a die grinder, electric or pneumatic, is a 
better tool - especially with foot operated speed control). When you 
line the gasket up, everything has a bit of play in it, so what I did 
was removed a bit more on the intake ports of the head, and also the 
exhaust manifold holes.  Some people actually recommend bigger exhaust 
manifold holes to create a "reversion dam"...  There is debate about 
whether or not it's a good idea, but with this less than perfect method 
of determining how much metal to remove you're better off with a step 
that opens up with the airflow instead jutting out into the airflow...
When you have removed the metal to the scribed lines "blend" it in to 
the ports over about one to two inches.

- Vacuum the crap out of everything (if you're extra-anal run the vacuum 
the whole time, sucking out the grit and metal before it gets a chance 
to get further into the head).  Pull out the rags, and then vacuum again.

- THEN blow the crap out of everything with an air hose.  Sand is a 
nasty thing to have in an engine.  You may even want to slowly turn the 
camshaft while blowing to make sure you get everything out of the ports.

- You're done!

HTH,

Mark.
75 x2
80 S
81 S x2
81 Caddy




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