Page 40 - April 2023

The Fixit Corner continues from page 39

It all started with 60 grit on a mini belt sander to remove
the casting marks, followed by 80 grit, 120, 180, 220, 400,
600, 800 and finally polish with Briliant Stainless and
Aluminum polish on a buff wheel and drill. I absolutely love
this polish!

I sanded so much that I went through a whole bottle of
Aleve during the process. The result is something most
people have never seen before; a TR6 intake manifold with
a chrome like shine, (good for at least 5 hp I?m sure) but a
perfect match for the polished SU carb dashpots, polished
Goodparts 621 header, and polished fuel pump. This
should make for a classy (and shiny) engine bay.

BTW that is the head covered in cardboard where I
mounted the manifold o during most of the process to
hold it in place while I sanded and polished. Of course, I
used a dust mask, and safety glasses for the entire
process.

Finally, to ensure the engine is tuned to the highest power
and efficiency, I bought a carb synchronizer tool, and a
AEM Air/Fuel (A/F) ratio sensor and gauge. This will allow
us to not only tune the idle mixture to the proper A/F ratio,
but we can also see what it is doing at higher RPMs.
On the SU carburetors, the idle mixture is controlled by
adjusting the position of the jet under the needle. The
mixture throughout the rest of the RPM range is controlled
by the varying thickness of the needle, piston spring
strength and oil thickness in the damper. If the mixture is
off at any point in the rpm range, the needle can be
modified or replaced to give more or less fuel at different
points in the range. There are over 300 needles available
to get the curve just right.

Sounds complicated, but hopefully using the A/F gauge to
measure the results will make things a bit easier. I can also
now connect it to a computer with tuning software if I
choose to do so. In the end I hope to have a clean running
engine operating at peak efficiency and power.

The next big decision is whether to paint the block red again or go back to the original gloss black. I have
heard mixed opinions. What do you think?
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