[Farmall] H Woes

[olmstead at ridgenet.net]

Hi, Mike!  I second Jim's suggestion about the timing light.  That'd tell
you a lot.

I only know of two ways to diagnose a problem like the one you described. 
The first requires divine intervention (or a healthy dose of dumb luck). 
That's the approach where you keep changing things and hoping that they'll
fix the problem, whether or not they make any sense.

The better approach is to approach this problem in a systematic manner. 
If it's a persistent miss on one particular cylinder, it has to be
something that only affects that one cylinder.  That pretty much rules out
timing, dirty gas and carburetor adjustment.

It could still be the distributor.  As others have mentioned, if the parts
start wobbling, you pretty much lose control of timing.  The timing light
will tell you a lot.

If the miss sounds like one cylinder only, I'd focus on things that only
affect one cylinder... leaky valves, intake manifold leaks or cracks, bad
plug wire or spark plug, etc.  You can pull or short a plug wire and find
out if it really is just one cylinder that is missing.  A compression
check would be a great idea.

I once had a Datsun 210 that ran great on the road but missed horribly on
one cylinder around town.  After days of fine tuning and tinkering, I
decided to clean the spark plugs.  I discovered that some "mechanic" had
dropped one plug and closed up the gap to almost nothing.  Two minutes
with feeler gauges and the car ran like new.

The biggest problem with a rebuilt engine is what you alluded to... you
can't really take anything for granted.  Incorrect cam timing, leaky head
gasket, leaky or stuck valve, incorrectly installed intake manifold
gasket, incorrectly adjusted rocker arms, bent pushrod.... have fun!

-Karl
---------------------------

>
> List,
>
> My employer has an H that has been in the family since new.   His son went
> through and rebuilt it a few years ago.   It does not run right.   It
> seems
> to miss, and doesn't have any power.   Supposedly the Carb has been
> rebuilt
> and all tuneup parts replaced.   The mechanic isn't much of a gasoline
> motor
> guy and while he does good work he is short on patience when he tries to
> work on a gasser that has an issue other than it is out of gas.   I have
> tried playing with it a little bit, and some things I've discovered:
> Changing the timing helps the miss, and the power, but it doesn't totally
> cure it.   Changing the timing also makes it impossible to crank start the
> old girl.  You can crank start it easily if the timing is set at one
> specific place.  I am timing by ear, no timing light involved.   I am
> almost
> tempted to say I think the automatic advance isn't working in the
> distributor.   I really hate to tear the thing apart and make it totally
> inoperable, so I am looking for any advice as far as what to look at and
> what I will find if I do tear that distributor apart.   Worn bushings?
> Worn Gears?   mucked up auto-advance?
>
>
> Many thanks on ideas on where to start.   I know I haven't given you much
> information but its been a couple weeks since I've messed with her and my
> memory isn't as good as it used to be :-)
>
> Thanks again
> Mike