Sounds like the rings are toast.
Colortunes are fine for setting idle mixtures--used them on motorcycles for
years. They can't handle the temperature and pressure of a dyno run, or
they'd be great for main jets settng too. They carbon up fairly quickly and
require careful cleaning. At one time I knew of a solvent that cleans them
well, but I don't recall what it was, only that it was a little exotic.
-----Original Message-----
From: owner-fot@autox.team.net [mailto:owner-fot@autox.team.net] On Behalf
Of WEmery7451@aol.com
Sent: Monday, August 07, 2006 8:52 AM
To: fot@autox.team.net
Subject: [FOT] Color Tune & MG Ideas
Dear FOT,
We were in Ireland for a couple of weeks to visit our middle daughter and
first born grandchild. Son-in-law told me that he was going to have the
engine torn out of his MG, and replaced. It was running poorly, gobbling
quart after quart of oil, and blowing a big smoke screen.
I noticed that the car was blowing black blotches onto the garage wall when
he started the engine, and figured that it was running rich. He had
recently bought a compression gage and a color tune tool. We adjusted the
mixture using the color tune tool: yellow-rich, blue-just right, and
white-lean. We then went for a test drive on the narrow, windy, road by the
Irish Sea between Dublin and Malihide. He said that the MG was now running
like a new car.
Question: Is there any application for using the color tune tool for setting
the mixture on a race engine?
I had bought a color tune tool years ago, but never got around to trying it.
I have always set the mixture by turning the jet nut out fifteen flats,
checking with a depth gage to see if the jets were down an equal amount, and
then occasionally looking at plugs after a run. Now I have installed an EGT
gage, which I can't easily see in the cockpit while racing. I can check the
difference in the two temperature readings after I stop.
The two sensors were mounted on the number one and number four cylinders.
We moved them to the number two and number three cylinders based on Kas's
recommendations.
The MG smoke screen was still there. We checked the compression on the four
cylinders. They were all relatively equal, only on the lower end of the
acceptable range. I then figured that there might be some decompression kit
installed under the head due to the 85-octane gasoline. At any rate, all of
that oil was not blowing past the rings.
There is a crank case breather hose that runs through a filter bolted on the
side of the engine, and then to the carburetors. We disconnected this hose,
and plugged the connection to the carburetors. The smoke screen was gone,
but oil was blown around under the hood - too much for installing a catch
tank.
We also discovered that we could no longer get the blue spark with the
breather hose disconnected from the carburetors.
The only thing that we can conclude is that the media in the filter is gone,
and maybe a little extra pressure is getting past the rings. The filter is
not readily available. We found one article showing the casing of this
filter being cut open, and a metal mesh pot and pan-scrubbing pad being
installed in it. The casing was then welded closed.
Any other ideas on the above problem would be appreciated.
|