I find it really easy to read plugs on motorcycles (especially air-cooled)
and really hard on cars. They just don't seem very sensitive. But I just
pulled the plugs from the cylinder head that was in place when I toasted
my number four piston, and lo and behold--I've got aluminum balls!
(they're much lighter than the old stock brass ones). The number three
cylinder had 'em too, though the piston looked ok.
-----Original Message-----
From: kas kastner [mailto:kaskas@cox.net]
Sent: Thursday, September 18, 2003 9:07 AM
To: Catpusher@aol.com; fot@autox.team.net
Cc: tarch@bellsouth.net
Subject: Re: Subject: ignition timing
One of the problems with the stock distributor is that the shaft is easily
bent and this leads to an alternate point gap for opposite cylinders.
Checking you will see that the static timing for example the number one
cylinder is perhaps 10 degrees, but when you turn the engine over to the
number four cylinder the timing is as much as 2 or 3 degrees less or MORE.
Therefore you have an engine that is operating with either too much timing
on alternate cylinder or not enough. In the end you find that though you
have programmed only 30 degrees of total timing into the engine you are in
fact carrying 32 degrees or more on other cylinders, and those cylinders
then are more prone to detonation.
In the end the check for detonation is the window to the combustion
chamber, the spark plug. Install clean (not necessarily new) plugs or even
a couple cleaned plugs and run a lap or test length, pull the plugs and
look for carbon specks and worse yet is tiny aluminum balls. If you find
the tiny aluminum balls on the center insulator of the spark plug, unless
you immediately do something about the timing the piston in that cylinder
is not long for this world. If you are doing this check on a race track
without air filters, do not confuse the tiny BLACK shiny balls for
aluminum. The tiny black balls are RUBBER. They don't appear black until
you look very closely and are easily confused in appearance with aluminum
which are also very shiny.
----- Original Message -----
From: <Catpusher@aol.com>
To: <fot@autox.team.net>
Cc: <tarch@bellsouth.net>
Sent: Wednesday, September 17, 2003 11:42 PM
Subject: Re: Subject: ignition timing
> > The way I set the ignition timing on my TR-4 is whilst driving to
> > the
race
> > and
> > cruising at say 4000 rpms, I press down on the accelerator and if
> > the
engine
> > pings, I stop and retard the spark. If it doesn't ping I advance it
until it
> > does then back off again until it doesn't do it any more. After
> > buying
race
> > gas at the track, I do it all over again during practice and then I
> > go
on to
> > worry about something else because this seems to always work.
>
> <HP>This may work for street use, and is the way I used to time my
> street TR3, but for a race motor the advance curve may exceed normal
> combustion at any point
> in the RPM range; and at high track speed you might not be able to hear
> abnormal combustion until it is too late.
>
> >>BTW: bronze valve guides should be honed, not reamed (trackside
emergencies
> excepted)
> Road Atlanta knows this!
>
> >
> > It also appears that the engine will run a little hotter if the
> > spark is retarded. This seems counter-intuitive, doesn't it?
>
> <HP> Retarded ignition sends the heat of combustion into the cooling
system,
> not out
> via the flywheel.
>
> >
> > So the question is, how do you real guys set your spark par excel
> > lance?
And
> > how do you check it for each cylinder?
>
> <HP> 1 and 4 are easy, but make certain that your timing light will
> work
at
> high
> RPM (many do not work well there)
>
> You have, I hope, verified the motor timing marks???
>
> On the Dyno, under Load, is the only safe way I know to do
this............
>
> Just mark the crank pulley for BDC & BDC max advance when you degree
> the
cam,
> and you have 2 & 3
>
> <HP>
>
> >
> > Richard Taylor
> >
> > TR-4
> >
> > Atlanta
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