Baffling Straight-8 Timing Problem

Hi,

I'm working with a friend on his 1931 Marmon 88 straight-8 engine. He
pulled the fully functional engine about a year ago, had the whole
thing miked out, replaced all the parts that needed it etc. in prep
for a rebuild to fix leaks and generally restore the engine. The
engine is now all back together, and we can get it to turn over and
run under its own power, but are having some serious complications
with timing it properly.

The problem we're running into is somewhat complicated and very
confusing, so I will explain it in detail in the hopes that we get
some useful advice.

1. The distributor worked perfectly in the car before the engine tear-
down. It's a dual-point distributor, and he's getting his
synchronization equipment ready to double-check, but it was
synchronized when the thing was taken apart and hasn't been touched
since.

2. We have verified that the cam and crank are timed correctly. They
were installed to spec using the embossed teeth on the timing gears to
align them for the installation of the timing chain, and we have
verified that at Cyl. No. 1 TDC (hereafter referred to simply as TDC)
the intake valve begins to open at exactly TDC on the intake stroke,
which is exactly as the Marmon manual (which he has, correct to his
year and model) specifies.

3. We have verified the firing order against the Marmon manual. I
believe, off the top of my head, that it is 1-6-2-5-8-3-7-4, but can't
confirm this- he has the book since it took him about 20 years to find
one in good condition. In any case, we have verified that the
distributor cap is wired correctly in that order.

4. We have verified that the distributor sparks Cylinder No. 1 at just
before TDC on the power stroke- in other words, we have statically
timed the engine to two flywheel teeth BTDC for the power stroke
according to the spec in the manual. We've verified that we're not 180
degrees out of time (of course, the engine wouldn't run at all if we
were, but we checked anyway).

So, the problem:

We can get the engine to start and run on its own. The starter motor
labours intensely to turn the thing over at correct static time, and
it barely starts and runs very ragged with *lots* of partially-
combusted gas in the form of black smoke in the exhaust. This is
frustrating but could be attributed to any number of things, but the
odd thing is: if we loosen the distributor bracket and *RETARD* the
timing by approximately 30 degrees of distributor rotation, which
corresponds (unless I'm mistaken) to 60 degrees ATDC, the engine runs
much smoother and cleaner, and the starter turns it over easily
instead of labouring. That's as far as we can retard the timing before
the condenser hits the retard arm spring screw and we can't turn it
any more. I would normally think that we should get better performance
out of the engine by advancing the timing, albeit at the cost of
hotter and less reliable valves.

Additionally, the more we choke the carb, the easier the thing is to
start and the better it runs, even with the throttle wide open it runs
better if we partially block the air intake.

The two "shots in the dark" we're going to take next time we drive the
50 miles to where the engine currently lives are a) checking the
timing with a dynamic timing light to see if it's flashing TDC when we
retard the distributor way past where we think TDC should be, and b)
checking the synchronization on the points.

Any ideas on what could be causing this? The distance between us and
the engine makes it inconvenient to go back and forth a lot, so we'd
appreciate any tips on things to look for when we try again after the
weekend.


Jon Harvey

wrote:
> Hi,
>
> I'm working with a friend on his 1931 Marmon 88 straight-8 engine. He
> pulled the fully functional engine about a year ago, had the whole
> thing miked out, replaced all the parts that needed it etc. in prep
> for a rebuild to fix leaks and generally restore the engine. The
> engine is now all back together, and we can get it to turn over and
> run under its own power, but are having some serious complications
> with timing it properly.
>
> The problem we're running into is somewhat complicated and very
> confusing, so I will explain it in detail in the hopes that we get
> some useful advice.
>
> 1. The distributor worked perfectly in the car before the engine tear-
> down. It's a dual-point distributor, and he's getting his
> synchronization equipment ready to double-check, but it was
> synchronized when the thing was taken apart and hasn't been touched
> since.
>
> 2. We have verified that the cam and crank are timed correctly. They
> were installed to spec using the embossed teeth on the timing gears to
> align them for the installation of the timing chain, and we have
> verified that at Cyl. No. 1 TDC (hereafter referred to simply as TDC)
> the intake valve begins to open at exactly TDC on the intake stroke,
> which is exactly as the Marmon manual (which he has, correct to his
> year and model) specifies.
>
> 3. We have verified the firing order against the Marmon manual. I
> believe, off the top of my head, that it is 1-6-2-5-8-3-7-4, but can't
> confirm this- he has the book since it took him about 20 years to find
> one in good condition. In any case, we have verified that the
> distributor cap is wired correctly in that order.
>
> 4. We have verified that the distributor sparks Cylinder No. 1 at just
> before TDC on the power stroke- in other words, we have statically
> timed the engine to two flywheel teeth BTDC for the power stroke
> according to the spec in the manual. We've verified that we're not 180
> degrees out of time (of course, the engine wouldn't run at all if we
> were, but we checked anyway).
>
> So, the problem:
>
> We can get the engine to start and run on its own. The starter motor
> labours intensely to turn the thing over at correct static time, and
> it barely starts and runs very ragged with *lots* of partially-
> combusted gas in the form of black smoke in the exhaust. This is
> frustrating but could be attributed to any number of things, but the
> odd thing is: if we loosen the distributor bracket and *RETARD* the
> timing by approximately 30 degrees of distributor rotation, which
> corresponds (unless I'm mistaken) to 60 degrees ATDC, the engine runs
> much smoother and cleaner, and the starter turns it over easily
> instead of labouring. That's as far as we can retard the timing before
> the condenser hits the retard arm spring screw and we can't turn it
> any more. I would normally think that we should get better performance
> out of the engine by advancing the timing, albeit at the cost of
> hotter and less reliable valves.
>
> Additionally, the more we choke the carb, the easier the thing is to
> start and the better it runs, even with the throttle wide open it runs
> better if we partially block the air intake.
>
> The two "shots in the dark" we're going to take next time we drive the
> 50 miles to where the engine currently lives are a) checking the
> timing with a dynamic timing light to see if it's flashing TDC when we
> retard the distributor way past where we think TDC should be, and b)
> checking the synchronization on the points.
>
> Any ideas on what could be causing this? The distance between us and
> the engine makes it inconvenient to go back and forth a lot, so we'd
> appreciate any tips on things to look for when we try again after the
> weekend.
>
>
> Jon Harvey
>

The only time I've seen this is when the distributer isn't in the
right position we fixed it by lifting up the distributer and dropping it
down again this would move it several degrees we did this several times
untill it ran well in the middle of the advance adjustment maybe a crude
way of doing things but it ran fine and timed ok.

On Sep 8, 1:11 am, wrote:
> Hi,
>
> I'm working with a friend on his 1931 Marmon 88 straight-8 engine. He
> pulled the fully functional engine about a year ago, had the whole
> thing miked out, replaced all the parts that needed it etc. in prep
> for a rebuild to fix leaks and generally restore the engine. The
> engine is now all back together, and we can get it to turn over and
> run under its own power, but are having some serious complications
> with timing it properly.
>
> The problem we're running into is somewhat complicated and very
> confusing, so I will explain it in detail in the hopes that we get
> some useful advice.
>
> 1. The distributor worked perfectly in the car before the engine tear-
> down. It's a dual-point distributor, and he's getting his
> synchronization equipment ready to double-check, but it was
> synchronized when the thing was taken apart and hasn't been touched
> since.
>
> 2. We have verified that the cam and crank are timed correctly. They
> were installed to spec using the embossed teeth on the timing gears to
> align them for the installation of the timing chain, and we have
> verified that at Cyl. No. 1 TDC (hereafter referred to simply as TDC)
> the intake valve begins to open at exactly TDC on the intake stroke,
> which is exactly as the Marmon manual (which he has, correct to his
> year and model) specifies.
>
> 3. We have verified the firing order against the Marmon manual. I
> believe, off the top of my head, that it is 1-6-2-5-8-3-7-4, but can't
> confirm this- he has the book since it took him about 20 years to find
> one in good condition. In any case, we have verified that the
> distributor cap is wired correctly in that order.
>
> 4. We have verified that the distributor sparks Cylinder No. 1 at just
> before TDC on the power stroke- in other words, we have statically
> timed the engine to two flywheel teeth BTDC for the power stroke
> according to the spec in the manual. We've verified that we're not 180
> degrees out of time (of course, the engine wouldn't run at all if we
> were, but we checked anyway).
>
> So, the problem:
>
> We can get the engine to start and run on its own. The starter motor
> labours intensely to turn the thing over at correct static time, and
> it barely starts and runs very ragged with *lots* of partially-
> combusted gas in the form of black smoke in the exhaust. This is
> frustrating but could be attributed to any number of things, but the
> odd thing is: if we loosen the distributor bracket and *RETARD* the
> timing by approximately 30 degrees of distributor rotation, which
> corresponds (unless I'm mistaken) to 60 degrees ATDC, the engine runs
> much smoother and cleaner, and the starter turns it over easily
> instead of labouring. That's as far as we can retard the timing before
> the condenser hits the retard arm spring screw and we can't turn it
> any more. I would normally think that we should get better performance
> out of the engine by advancing the timing, albeit at the cost of
> hotter and less reliable valves.
>
> Additionally, the more we choke the carb, the easier the thing is to
> start and the better it runs, even with the throttle wide open it runs
> better if we partially block the air intake.
>
> The two "shots in the dark" we're going to take next time we drive the
> 50 miles to where the engine currently lives are a) checking the
> timing with a dynamic timing light to see if it's flashing TDC when we
> retard the distributor way past where we think TDC should be, and b)
> checking the synchronization on the points.
>
> Any ideas on what could be causing this? The distance between us and
> the engine makes it inconvenient to go back and forth a lot, so we'd
> appreciate any tips on things to look for when we try again after the
> weekend.
>
> Jon Harvey

It's a quickie and unlikely, but I would stick a probe into cylinder
#1 and make sure that it was sticking up the highest when the
(flywheel?) pointer said that it should be.
In other words, is "TDC" on the timing gauge the same as with the
piston itself?

On Sep 8, 3:37 pm, Stude > wrote:
> On Sep 8, 1:11 am, wrote:
>
>
>
> > Hi,
>
> > I'm working with a friend on his 1931 Marmon 88 straight-8 engine. He
> > pulled the fully functional engine about a year ago, had the whole
> > thing miked out, replaced all the parts that needed it etc. in prep
> > for a rebuild to fix leaks and generally restore the engine. The
> > engine is now all back together, and we can get it to turn over and
> > run under its own power, but are having some serious complications
> > with timing it properly.
>
> > The problem we're running into is somewhat complicated and very
> > confusing, so I will explain it in detail in the hopes that we get
> > some useful advice.
>
> > 1. The distributor worked perfectly in the car before the engine tear-
> > down. It's a dual-point distributor, and he's getting his
> > synchronization equipment ready to double-check, but it was
> > synchronized when the thing was taken apart and hasn't been touched
> > since.
>
> > 2. We have verified that the cam and crank are timed correctly. They
> > were installed to spec using the embossed teeth on the timing gears to
> > align them for the installation of the timing chain, and we have
> > verified that at Cyl. No. 1 TDC (hereafter referred to simply as TDC)
> > the intake valve begins to open at exactly TDC on the intake stroke,
> > which is exactly as the Marmon manual (which he has, correct to his
> > year and model) specifies.
>
> > 3. We have verified the firing order against the Marmon manual. I
> > believe, off the top of my head, that it is 1-6-2-5-8-3-7-4, but can't
> > confirm this- he has the book since it took him about 20 years to find
> > one in good condition. In any case, we have verified that the
> > distributor cap is wired correctly in that order.
>
> > 4. We have verified that the distributor sparks Cylinder No. 1 at just
> > before TDC on the power stroke- in other words, we have statically
> > timed the engine to two flywheel teeth BTDC for the power stroke
> > according to the spec in the manual. We've verified that we're not 180
> > degrees out of time (of course, the engine wouldn't run at all if we
> > were, but we checked anyway).
>
> > So, the problem:
>
> > We can get the engine to start and run on its own. The starter motor
> > labours intensely to turn the thing over at correct static time, and
> > it barely starts and runs very ragged with *lots* of partially-
> > combusted gas in the form of black smoke in the exhaust. This is
> > frustrating but could be attributed to any number of things, but the
> > odd thing is: if we loosen the distributor bracket and *RETARD* the
> > timing by approximately 30 degrees of distributor rotation, which
> > corresponds (unless I'm mistaken) to 60 degrees ATDC, the engine runs
> > much smoother and cleaner, and the starter turns it over easily
> > instead of labouring. That's as far as we can retard the timing before
> > the condenser hits the retard arm spring screw and we can't turn it
> > any more. I would normally think that we should get better performance
> > out of the engine by advancing the timing, albeit at the cost of
> > hotter and less reliable valves.
>
> > Additionally, the more we choke the carb, the easier the thing is to
> > start and the better it runs, even with the throttle wide open it runs
> > better if we partially block the air intake.
>
> > The two "shots in the dark" we're going to take next time we drive the
> > 50 miles to where the engine currently lives are a) checking the
> > timing with a dynamic timing light to see if it's flashing TDC when we
> > retard the distributor way past where we think TDC should be, and b)
> > checking the synchronization on the points.
>
> > Any ideas on what could be causing this? The distance between us and
> > the engine makes it inconvenient to go back and forth a lot, so we'd
> > appreciate any tips on things to look for when we try again after the
> > weekend.
>
> > Jon Harvey
>
> It's a quickie and unlikely, but I would stick a probe into cylinder
> #1 and make sure that it was sticking up the highest when the
> (flywheel?) pointer said that it should be.
> In other words, is "TDC" on the timing gauge the same as with the
> piston itself?

Thanks Stude, and that's a good thought. We checked that at least it
was beginning compression when it's supposed to via the puff test
(kleenex on top of the plug hole) but we didn't try a probe. We'll do
that.

Mark, I'm unclear as to how picking up and reinstalling the
distributor could change it. I'm pretty sure that distributors can
only go in one of two ways- in time, or 180 degrees out of time-
because typically the end of the rotor has a horizontal notch that
corresponds to a horizontal bar on the helical gear from the cam. You
say that "this would move it several degrees we did this several times
untill it ran well in the middle of the advance adjustment", which
seems to indicate that you can improperly install a distributor in
such a way that it is not 180 degrees out of time, but nonetheless
isn't timed right. What would cause the distributor to be partially
out of time like that?

Thanks for the input so far, and I'll keep posting on what we try.
We're probably going up there again on Monday.

wrote:

> Any ideas on what could be causing this?

Check the valve clearance. If they milled the head or block a bit during the
rebuild, this will have changed.

George Patterson
If you torture the data long enough, eventually it will confess
to anything.

All of the above are good suggestions.

I was thinking along the same line as George. Many engine rebuilds,
although within manufacturers' specs, often cause problems that didn't
exist prior to the rebuild. If the engine was put together as "tight"
as possible, i.e. at the closest limits of recommended tolerances,
this can cause a host of problems such as an engine to run
excessively hot for example or to be nearly impossible to start. Even
though everything is within specs according to the book, the compound
effect of this is a "too tight" engine.

Any machining of the block and head will affect the valve clearance. A
thicker head gasket may be necessary to return things to the proper
position.

Regarding Mark's idea to move the distributor: All cars are different,
of course, and I have no experience with Marmon straight 8's, however,
it is possible to install a distributor incorrectly without it being
180' out of time. The worm gear at the base of the distributor shaft
has to engage the drive gear in exactly the right place or the rotor
will be moved slightly one way or the other.

Set the engine itself at #1 TDC as described earlier.
Set the rotor to point exactly at #1wire.
Slip the shaft down the hole and watch the rotor.
If the rotor moves one way or the other, pull the Dist. out and rotate
the shaft in the OPPOSITE direction of the previous rotor movement
until the rotor moves the same distance in the opposite direction from
it's original starting position (#1 wire).
When reinstalling the distributor, the rotor should now move in the
same direction as it did the first time and should stop at TDC.

Even though the distributor worked before the rebuild, don't assume
anything. Check it thoroughly. The Dist. cam could be excessively
worn. Check the spring tension of the breaker points. (a special tool
is made for this) Weak spring tension can cause point chatter
(bouncing) and excessive tension will cause extreme wear of the
rubbing block, cam and points.

You don't say whether the distributor was rebuilt along with the
engine, only that it worked before the rebuild. Check the bearings at
the top and bottom of the Dist. shaft. If they are worn or the wrong
size, etc. you will get side play of the Dist. shaft. Side play causes
irregularities in timing. This can be checked with a dial indicator.
If the side play exceeds specs, the bearings and/or the shaft will
have to be replaced.

A slightly bent Dist. shaft could also cause these problems.

Double check your coil too.

Check the spark output on each plug wire. A weak or intermittent spark
at all the wires points to the coil, Dist. cap, rotor, or high tension
wire from the coil to the Dist. I know this sounds extremely basic but
sometimes it's the simple things. I once went through a whole
diagnostic rig-a-ma-role on a 1972 Monte Carlo because I took my dad's
word for it that he filled up the tank. He in fact had only put a
couple dollars in it and had run out of gas.

I hope you solve this problem. Please let us know what finally works
out. If any new information comes to light, tell us about it.

On Sep 8, 4:47 pm, wrote:
> On Sep 8, 3:37 pm, Stude > wrote:
>
>
>
>
>
> > On Sep 8, 1:11 am, wrote:
>
> > > Hi,
>
> > > I'm working with a friend on his 1931 Marmon 88 straight-8 engine. He
> > > pulled the fully functional engine about a year ago, had the whole
> > > thing miked out, replaced all the parts that needed it etc. in prep
> > > for a rebuild to fix leaks and generally restore the engine. The
> > > engine is now all back together, and we can get it to turn over and
> > > run under its own power, but are having some serious complications
> > > with timing it properly.
>
> > > The problem we're running into is somewhat complicated and very
> > > confusing, so I will explain it in detail in the hopes that we get
> > > some useful advice.
>
> > > 1. The distributor worked perfectly in the car before the engine tear-
> > > down. It's a dual-point distributor, and he's getting his
> > > synchronization equipment ready to double-check, but it was
> > > synchronized when the thing was taken apart and hasn't been touched
> > > since.
>
> > > 2. We have verified that the cam and crank are timed correctly. They
> > > were installed to spec using the embossed teeth on the timing gears to
> > > align them for the installation of the timing chain, and we have
> > > verified that at Cyl. No. 1 TDC (hereafter referred to simply as TDC)
> > > the intake valve begins to open at exactly TDC on the intake stroke,
> > > which is exactly as the Marmon manual (which he has, correct to his
> > > year and model) specifies.
>
> > > 3. We have verified the firing order against the Marmon manual. I
> > > believe, off the top of my head, that it is 1-6-2-5-8-3-7-4, but can't
> > > confirm this- he has the book since it took him about 20 years to find
> > > one in good condition. In any case, we have verified that the
> > > distributor cap is wired correctly in that order.
>
> > > 4. We have verified that the distributor sparks Cylinder No. 1 at just
> > > before TDC on the power stroke- in other words, we have statically
> > > timed the engine to two flywheel teeth BTDC for the power stroke
> > > according to the spec in the manual. We've verified that we're not 180
> > > degrees out of time (of course, the engine wouldn't run at all if we
> > > were, but we checked anyway).
>
> > > So, the problem:
>
> > > We can get the engine to start and run on its own. The starter motor
> > > labours intensely to turn the thing over at correct static time, and
> > > it barely starts and runs very ragged with *lots* of partially-
> > > combusted gas in the form of black smoke in the exhaust. This is
> > > frustrating but could be attributed to any number of things, but the
> > > odd thing is: if we loosen the distributor bracket and *RETARD* the
> > > timing by approximately 30 degrees of distributor rotation, which
> > > corresponds (unless I'm mistaken) to 60 degrees ATDC, the engine runs
> > > much smoother and cleaner, and the starter turns it over easily
> > > instead of labouring. That's as far as we can retard the timing before
> > > the condenser hits the retard arm spring screw and we can't turn it
> > > any more. I would normally think that we should get better performance
> > > out of the engine by advancing the timing, albeit at the cost of
> > > hotter and less reliable valves.
>
> > > Additionally, the more we choke the carb, the easier the thing is to
> > > start and the better it runs, even with the throttle wide open it runs
> > > better if we partially block the air intake.
>
> > > The two "shots in the dark" we're going to take next time we drive the
> > > 50 miles to where the engine currently lives are a) checking the
> > > timing with a dynamic timing light to see if it's flashing TDC when we
> > > retard the distributor way past where we think TDC should be, and b)
> > > checking the synchronization on the points.
>
> > > Any ideas on what could be causing this? The distance between us and
> > > the engine makes it inconvenient to go back and forth a lot, so we'd
> > > appreciate any tips on things to look for when we try again after the
> > > weekend.
>
> > > Jon Harvey
>
> > It's a quickie and unlikely, but I would stick a probe into cylinder
> > #1 and make sure that it was sticking up the highest when the
> > (flywheel?) pointer said that it should be.
> > In other words, is "TDC" on the timing gauge the same as with the
> > piston itself?
>
> Thanks Stude, and that's a good thought. We checked that at least it
> was beginning compression when it's supposed to via the puff test
> (kleenex on top of the plug hole) but we didn't try a probe. We'll do
> that.

Let's hope thet the sparkplug is above the piston, not the valves <g>

> Let's hope thet the sparkplug is above the piston, not the valves <g>

The best way would be with a compression gauge. As soon as it reaches
the maximum, it's at TDC. If you end up having to take the head off,
get the piston at TDC before putting it back on.

This may also seem basic but make sure you know which way the
distributor rotor rotates -clockwise or counter-clockwise. Many people
just assume that it rotates clockwise as viewed from above. Different
engines turn different directions. Even within the same manufacturer,
some turn clockwise, some turn counter-clockwise.

Assuming one when it's the other will throw the whole game off.

Take the cap off and look at it while somebody bumps the starter just
to be sure.

I seriously doubt any issues with surfacing the cylinder head or block
deck surface causing any issues related to what it mentioned.
Typically, there was enough extra metal in those areas to allow for
resurfacings of that nature. Taking a .010" off of the head surface
would mean the valve adjustment nut might not be tightened to the same
location on the rocker arm (or whatever) as it was before the surfacing
was done, but it'll still allow for proper adjustment without causing
any issues to starting the motor providing the valves are adjusted
correctly.

Knowing the distributor rotor's direction of rotation is important to
knowing if you're advancing or retarding the basic timing position. To
advance the time, you turn the distributor body "into" the direction of
rotor rotation and retard it by turning the distributor body "with"
rotor rotation.

If the dual point system on that vehicle is as with other later model
systems, getting the points adjusted to the correct point gap is what
"phases" them and gets to the correct point dwell readings. In essence,
the second set "does its thing" as the first set gets ready to conclude
"doing its thing" such that "dwell" readings for the combined point set
is greater than it would be for either one individually OR one set with
enough point gap to get to the same point dwell value. IF they were
correct to start with, they probably still are. What you might do is
make sure the point contacts are clean and not gunked with accumuated
stuff from sitting around during the rebuild.

If the distributor has a bottom-of-the-shaft piece that indexes with the
drive gear either "in" or "180 out" (as a B/RB Chrysler V-8 does),
rather than having a gear on the bottom which also has the oil pump
drive on the bottom of it (as a small block Chevy V-8 does), then how
the oil pump drive gear is positioned and indexed is highly important.

In the case of the small block Chevy distributor, it has the drive gear
held to the bottom of the main shaft of the distributor. On the bottom
side of the gear's "neck" is where it indexes with the oil pump drive
shaft on the oil pump, as the distributor assembly is dropped into the
motor. If you've done something like this, you know that as the
distributor is removed, the rotor turns a particular direction and does
opposite when it's put back into the motor. So what might have been
done initially, but not thought about then, was to take the engine to #1
TDC and mark the rotor's position on the distributor body in the "as it
used to run" situation.

On the Chrysler B/RB engines (i.e., 383-413-440), how the distributor
drive gear is indexed with the camshaft as it also drives the oil pump,
too, is highly important. In effect, it's the same thing as having a
two-piece distributor shaft on a Chevy V-8. As the drive gear spirals
down and engages the oil pump drive shaft, the final position must be
"right on" if the distributor is to be "in time". There are pictures of
how that slot is positioned at final assembly in the Chrysler service
manuals. Once that drive gear is in the right position, then the "in"
or "out" set-up for the distributor works easily and "bullet-proof".

IF you have the base timing set correctly (with respect to the
crankshaft/flywheel position), yet it runs better and starts easier with
turning the distributor a distance of what amounts to "one spark plug
wire away from the perceived-to-be correct setting", that usually
indicates "one tooth off" in the distributor gear to camshaft gear
interface. It can ALSO mean "one tooth off" in the basic camshaft
timing gear area too.

One time in the middle 1970s, I was at a local Chrysler dealership when
a State Trooper Plymouth was brought in for running poorly (which it
was). In order to get it started, they had to move the distributor
around some. Then they put a timing light on it to see where the timing
was. At the stock base timing setting, it ran like crap, with backfires
and such with any throttle input, but once running, the old-line
Chrysler service manager turned the distributor about one notch advanced
and the engine ran much better. A quick diagnosis for a
jumped-one-tooth timing chain which was accurate.

In later years, when I was around more shade tree mechanic friends, you
could tell those that knew now to drop a distributor in a Chevy small
block as to how the vac advance can was aimed. Or in later years, how
the cross bar on the HEI coil was not aligned parallel with the
vehicle's cowl structure.

Therefore, if you've got to move the distributor around that much to get
it to run correctly, you'll need to check ALL of the indexes for
everything below the distributor itself. If the distributor indexes
with a slot in an oil pump drive gear, which is run from a gear on the
camshaft, then that will need to be completely accurate for the
distributor to be correctly positioned at #1TDC.

One other thing to be cognizant of is that on a small block Chevy V-8,
when the timing gear indicators are "dot-to-dot", #6 cylinder is firing
rather than the suspected #1 cylinder firing. When the "dots" are in a
straight line, but not together, then THAT's when #1 cylinder is firing.
Whether a similar situation exists with your engine, I have no idea, but
it's something to consider in your diagnosis situation.

Similarly, it's also easy to miss the "dot-to-dot" situation, too, so
making sure that is correct on the timing gears/chain is important, too,
even if you thought it was correct to start with.

To find "real" #1TDC, using the "probe" is a good idea. The 'best next"
thing would be using a dial indicator with the cylinder head off, but
for what you're trying to do, a straw or something similar might work as
well. There are some special tools for this sort of thing, in the hot
rod aftermarket, but careful use of a proper "soft" probe can work just
as well. I suspect that if it's anywhere close to what they should be,
things will be assembled "as desired", but that could be a little
variable.

So, you can check the valves for correct settings (which should be done
anyway), but I highly suspect you'll find your real issues with the
indexing of the distributor drive gears with respect to the camshaft.
If that checks out, then look at the camshaft drive gears/chain sproket
area. If the front side things need adjustment, then double check the
distributor drive gear settings after that front side repositioning to
make sure the TOTAL situation is positioned as it should be.

Just some thoughts . . .

C-BODY