Camshaft Gear and Crankshaft gear Timing

[frank folkmann]

The 75-76 manual states "When timing marks are in alignment, number six is
at T.D.C. to obtain T.D.C. for number one cylinder, slowly rotate
crankshaft one rotation, this will bring the cam mark to the top,number one
will then be in the firing position. What I did. Number one cylinder T.D.C.
Camshaft and Crankshaft marks aligned Distributor set to number one
cylinder. Will this not accomplish the same thing?

Frank SW Indiana

 

[frank folkmann]

Thanks Lorry

>
>

>
>> The 75-76 manual states "When timing marks are in alignment, number six is
>> at T.D.C. to obtain T.D.C. for number one cylinder, slowly rotate
>> crankshaft one rotation, this will bring the cam mark to the top,number one
>> will then be in the firing position. What I did. Number one cylinder T.D.C.
>> Camshaft and Crankshaft marks aligned Distributor set to number one
>> cylinder. Will this not accomplish the same thing?
>>
>> Frank SW Indiana
>
>Frank,
>
>No. When the crank and cam marks are in alignment, # 6 cylinder is at TDC
and
>in the firing position (compression stroke completed, both valves closed,
ready
>to fire). At this same time, # 1 cylinder is ALSO at the top of the
bore but
>it not at TDC. #1 has just completed the exhaust stroke and is ready to
start
>on the intake stroke (exhaust valve closed, intake valve ready to open). If
>you set the distributor to fire cylinder #1 in this configuartion, it will
>backfire up through the carb.
>
>You need to align the crank and cam marks (putting #6 at TDC), then rotate
the
>crank one revolution which will put #1 at TDC. Set the distributor to #1 and
>you are off to the races.
>
>The confusion may come from the terminology. TDC doesn't just mean that the
>piston is at the top of the bore. It also means that the cam is in the
proper
>position for both the intake and exhaust valves to be closed so that the
>cylinder can fire.
>
>HTH,
>
>Lorry
>

 

[lorry clavelli]

> The 75-76 manual states "When timing marks are in alignment, number six is
> at T.D.C. to obtain T.D.C. for number one cylinder, slowly rotate
> crankshaft one rotation, this will bring the cam mark to the top,number one
> will then be in the firing position. What I did. Number one cylinder T.D.C.
> Camshaft and Crankshaft marks aligned Distributor set to number one
> cylinder. Will this not accomplish the same thing?
>
> Frank SW Indiana

Frank,

No. When the crank and cam marks are in alignment, # 6 cylinder is at TDC and
in the firing position (compression stroke completed, both valves closed, ready
to fire). At this same time, # 1 cylinder is ALSO at the top of the bore but
it not at TDC. #1 has just completed the exhaust stroke and is ready to start
on the intake stroke (exhaust valve closed, intake valve ready to open). If
you set the distributor to fire cylinder #1 in this configuartion, it will
backfire up through the carb.

You need to align the crank and cam marks (putting #6 at TDC), then rotate the
crank one revolution which will put #1 at TDC. Set the distributor to #1 and
you are off to the races.

The confusion may come from the terminology. TDC doesn't just mean that the
piston is at the top of the bore. It also means that the cam is in the proper
position for both the intake and exhaust valves to be closed so that the
cylinder can fire.

HTH,

Lorry