Re: 350 Timing, It\'s Pi$$ing me off!
Since you didn't have it apart it could have jumped time on
I wouldn't keep trying to start it anymore until you do the
following, as you may damage more than has already been done.
Usually, but not always the following check works.
Rotate the crank by hand at least 1/2 turn until the mark
is at 0 or close to it. Make sure you don't let it rock
back - keep it moving in the same direction.
Note where the line is.
Remove distributor cap.
Watch the distributor rotor, slowly and carefully turn the
crank in the opposite direction from you already turned it -
until the rotor just barely starts to move.
Measure how far it went before the rotor moved. You can
approximate how far in degrees by using the timing marks
as your guide.
What you did was get all the chain's slop on one side, then
when you turned the crank backwards it all had to transfer
to the other side before the cam/distributor can move.
You measured the amount of "looseness."
Generally a new regular chain will have about 4-6 degrees
A true double roller's about 2 or less.
A worn chain that should be replaced will be about 12 or
more degrees of slop.
At somewhere around 15 degrees of total slop they can, but
not always, jump.
I've seen them as high as 19-20 and still run fine, but not for
long. That's so loose you can take the chain off without
removing the bolts.
Yes it can run, barely, if it's jumped just one tooth.
Jumping 2 or more can destroy things, like valves, pistons
Check it twice to make sure your results are accurate.
Then, if it passes that test:
If it has an EGR, take a close look at it.
It could be stuck open from carbon.
When an EGR valve's open at idle or slow speeds it's diluting
the mixture way too much with inert, unburnable exhaust
But - you can get it to run if you advance the timing way
ahead, like 30-45 degrees.
By lighting it that far ahead you are creating enough cylinder
pressure to run, but not well. It usually won't feel like a
misfire, just gutless.
Check the EGR Valve, exhaust crossover under the carb - if
it has one, and the crossover in the manifold - anyplace the
exhaust gasses could be getting back in the induction system.
Let us know on this thread what you find.