Bill Noble wrote:

"Steve W." wrote in message
...
Bill Noble wrote:
so the metal is my car's engine - a horizontally opposed 6, that has
some air passages (supplementary air injection) that are clogged by
carbon,

snip

So, any ideas? (I've used spray carb cleaner and fuel injector
cleaner, the former works a lot better than the latter) - I've tried
wire probes (access is quite limited), a micro rotor-rooter type thing I
made from a speedo cable, and other mechanical means - none worked worth
a darn.

GM Top cylinder cleaner OR Sea Foam. Both work well for this.

Move vehicle OUTSIDE!!!

Start engine let it warm up.
Pull off a vacuum line ABOVE the areas you want to de-carbon.
VERY IMPORTANT STEP.

Now with the engine idling allow the engine to draw 1/2 - 3/4 of the can
of cleaner into the hose. When it gets to that point invert the can and
stall out the engine with the cleaner (it won't lock up, just quit
because of the mix). Now let it set for 1/2 - 1 hour. When you start it
back up you will get a HUGE cloud of smoke with a LOT of carbon in it.
Make sure your exhaust isn't pointed towards anything you want to keep
clean. Run it a bit until the smoke clears up, then change out the
oil/filter, you may want to do this again after a couple days. There
will be a LOT of carbon and crud flushed into the oil.



--
Steve W.

ok, so top cleaner or sea foam - right..... how do these things go about
doing their job? I ask because the carbon in question is not inside the
combustion chamber - so putting the goop into the intake will do nothing
- the car runs perfectly. The problem is some passages wtihin the head
that connect to little tiny ports above each exhaust valve. The ports
are in the manifold section, not in the cylinder internals, so they are
not under engine pressure.

This site here http://www.systemsc.com/pictures.htm has a good
description of the problem, though I don't agree with the guess at the
cause. My car in particular does not burn inappropriate amounts of oil
and it has 130K miles - the problem first appeard well after 100K, so
my theory is that if I can get a goodly fraction of this carbon out, I
should be good for another 100K miles or so before it comes back

I have made block off covers, so I can block off all but one exit and
pressurize the system - this will sometimes pop out whatever is blocking
the one port, but some times not. I could pour lots of sea foam into
the air passage where the pump blows in air and hope for the best, and I
can keep it there by plugging up the little exit ports that go into the
head.

If the passages get hot enough to cause carbon it will work. The
question will be getting the cleaner into the passages. In this case you
could heat up the car, then spray the cleaner into the air injection
intake.
It works by breaking the bonds in the carbon chemically. the trick will
be getting it into the passages.
IF you could get some 1/8" stiff tubing you could shove it into the
passages and spray through that.

--
Steve W.