- Hi, I'm Kyle Smith with Hagerty.
Today we are going to be adjusting a timing
on a 350 Chevy small block
that happens to be in this 1972 Chevrolet pick up.
So today we just need a couple simple tools,
one will be a standard 9/16 open inch wrench,
and the other is our one specialty tool
that we've needed and that will be our timing light.
And then of course the wires associated to it.
And we'll go into how to use this one here in just a moment.
There's a couple reasons you might need to
reset the timing on a give an engine.
The first is if you've recently disassembled the engine
or remove the distributor.
You want to make sure everything is back in sync
prior to starting it for the first time,
or even starting it for the first time in a long time.
The second being if you've made changes to the distributor
or the overall engine set up,
such as changing the fuel that the engine will run on
or going from a point style ignition
to an electronic ignition style set up.
On this engine that were working on today
it is an HEI ignition so it is an electronic ignition
so we're not dealing with points or the well set up today.
So, there's two safety considerations
that I'll be taking in today.
One, I will be wearing safety glasses
just in case something were to fly off
of the engine while it's running.
The second is I have to be mindful of the mechanical fan.
This does have a standard metal flex fan
and for me to get my hand caught in that
would be a very bad day.
If you have electric fans you still need to be cautious,
but less so, most of those are fairly well guarded,
but it's just something we need to keep in mind.
So we'll go ahead and remove the air cleaner
just to make it a little bit easier,
both for me to reach the distributor,
and for you to see what I'm doing today.
So this is a fairly fresh restoration that we're working on
and when we put the engine in the truck and
we got everything initially set up
we set on the safe side which is slightly retarded
so it should start, and run, but
it's probably going to run a little bit rough.
We'll go ahead and fire it up and let you guys
hear what it sounds like now that it's
running just a little bit retarded.
(engine rumbing)
So you can hear this one, it's missing just a slight bit.
It's running just a little bit rougher
than it truly needs to.
As we get the timer closer and closer
to where it needs to be, it's going to run
smoother and smoother, have a lot better idle to it.
So at step one here and the first thing
that we're going to do is actually remove something,
and that is the vacuum advance,
so you can see here where the vacuum advance
is located on the side of the distributor.
There can be many different styles
but what it comes down to, is there should only be one
vacuum line running to the distributor,
so it will be very easy to spot.
So you'll see it's a small vacuum hose
that goes to a port on the carburetor,
you want to remove this and plug the line
so that we don't have a vacuum leak
going into the carburetor.
The reason we want to remove the vacuum advance
is so that we don't have any mechanical advance
or vacuum advance taking the distributor over
while we're trying to set that base timing.
The vacuum advanced functions
while the engine's at higher RPM,
or when you lay into the pedal as you're driving,
gives it just a little more advance so it's peppier.
Our next step, or our second step in this process,
we're actually going to take our 9/16 wrench,
we're going to loosen the distributor hold down
that's tucked right here at the base of the distributor.
Most standard Chevy small blocks
are going to have the same 9/16 size wrench.
I'm not sure of exactly what it is on Ford
so check your service manual and
make sure you've got the correct one.
This is the last bolt you want to round off on an engine.
As you loosen it up, you'll want it to where the distributor
still holds tight while it's running,
but you'll want to be able to move it
just a little bit by hand.
So you can see as I'm moving that back and forth,
it's still holding in it's place,
it's not fully rotating, but it allows me to move that.
Step number three brings in our first specialty tool
and that is our timing light.
So there's three connections that we need to make
on this one so it will do it's job.
The first one is going to be this inductive pick up
which senses when there is power going through
the number one spark plug wire.
So on a small block Chevrolet,
on the driver's side, all the way to the front of the engine
is going to be cylinder number one.
This is the odd numbers and those are the even numbers.
So we'll mark cylinder number one spark plug wire
and put the inductive pick up on there,
and then we have to power the timing light
with our standard two leads,
so we will go the negative terminal
and the positive terminal on the battery.
So there are many different timing lights
available for sale.
This one does have the option that you can adjust
exactly where you want the timing to be,
and then you adjust so the timing marks
line up at zero degrees.
I prefer to use this marked to zero,
so it's just flashing exactly when
the spark is going through that spark plug wire,
and then I use the marks on the engine.
It really depends on how your engine is set up,
or what your preference is, there's many
different ways to do it, this is just my method.
So what we are actually going to be using
to time the engine is these teeth marks right here
that come off of the timing chain cover,
and then there will be a mark on our
harmonic balancer or the main engine pulley.
As the timing light flashes with the spark
going to the number one cylinder,
it's going to show where the mark is
on the harmonic balancer against those marks
coming off the timing cover.
Those marks are going to tell us
exactly where the timing is set.
So whether it be 10 degrees before or
advanced or after or retarded,
we'll be able to rotate the distributor
to adjust where that mark is hitting,
where that spark is arriving in the cylinder.
(engine roaring)
So what I was adjusting that to
and our actual timing marks,
I wanted about 12 degrees before top dead center
or 12 degrees advanced.
We were looking at the timing marks coming off
of that timing cover to the marks on the balancer
and you can hear the engine smoothed out significantly,
just by bringing that into where it needs to be.
Look it up in your factory service manual
where you need to adjust it to
or consult a professional engine builder
if it's a custom application.
At this point you might be thinking to yourself,
"Why is timing so important and shouldn't I
"just go one direction over the other?
"Or even, why don't I just align it at straight up
"to where the spark is arriving at top dead center."
Now there's a couple things to discuss with that.
So when were looking at it too far advanced
or too far retarded for when the cylinder is getting a spark
can both have negative consequences.
One, however, is worse than the other.
If you retard the spark too much,
the engine will struggle to run, even if it runs at all,
and that's simply because the piston
is already on its way down through the combustion stroke,
when that cylinder is being ignited.
That means it does not have sufficient time to burn
all the air and fuel, it's not maximizing the potential
of that compressed air and fuel.
On the opposite side, if you have it too far advanced,
what's happening is, you are detonating
all of the compressed air and fuel
before the piston has reached top dead center
and that means essentially, the engine
is now fighting itself, it's a quick way
to end up with holes in pistons or
some really nasty cylinder heads,
especially if you have aluminum heads.
Something to be cautious of, because often times
you need to run on the advanced side
for a smooth running engine, but too much,
is very much dangerous.
So now we're going to go ahead and
disconnect our timing light and then we will
tighten down the hold down for the distributor
and reconnect our vacuum advance,
and then we'll see how it runs.
(engine rumbling)
Looks like we've got it running nice and good,
idling nice and smooth.
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