Joe,
Installing a header...and what you are talking about are two different
things!
Port matching is just that!...maybe a little material removed from the
header...maybe a little from the head! The initial fit should tell you
whether or not you have a poorly manufactured header... you wouldn't
want to remove a great deal of material from one port on the head just
to make the header fit!
NOTE: This is normally done with the head removed!
The actual procedure involves the use of DyKem steel blue in order to
get an idea as to how the two parts mate up.
As you pointed out...you need some sort of an accurate, repeatable,
baseline to go by...The header has to be worked until the smallest
possible clearance between the fasteners can be achieved. The port
matching will only be as accurate as the tolerance of the mounting
position. I use dowel pins...holes must be precisely reamed into the
head and corresponding parts, for both the intake and header. This
allows the header and intake manifold to be accurately mounted over and
over again to .001".
Spray the header mating surfaces with steel blue...immediately press the
header against the head and remove. There will be an imprint of the
header ports on the cylinder head...from this you can get a visual as to
far they are off.
If the header openings are slightly larger than the cylinder head
ports...I would leave well enough alone...and enjoy the added torque.
On the other hand if one of the header ports slightly overlaps one of
the head ports, I would make the correction with a die grinder. If it's
way off...scrap the header!
You will find DyKem by following the link below...
http://www.mscindustrial.com/
Best regards,
Jim Swarthout
-----Original Message-----
Subject: fitting Header
Hi list
About the time I'm about to give up on fitting my "free" Monza style
headers, I've finally got the flange square to the head. Next problem:
How
do you ensure that the ports are matched up? It seems pretty easy to
move
this thing around on the studs. Of course, one movement here, creates
another movement there. I'm sure there is a secret to this. Anyone
want to
share it?
(very close to going to a stock manifold)
Joe Davis
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