Dead cylinder

[smlk31]

I have a 100 series ford and have a dead cylinder. good spark to plug new plugs all around compression 95/100 running. not sure where to go from here other than take the valve cover off and see if anything is amiss. Thoughts??

 

[SkipperII]

Compression 95/100psi running??? Compression is tested with the sparkplugs removed and cranking with the starter. First of all, do a proper
compression test(get a repair manual}. If your compression is 110-125+ and the lowest cylinder is within 10% of the highest, it is
acceptable. You may have a vacuum leak. But please, get a repair manual.

 

[DanielW]

Some of those fords were known to bend pushrods when the valves got stuck -
either from rust or varnish build up o the stem. Maybe something like that has
happened and you have a valve stuck closed, in which case taking the valve
cover off and watching as it cranks might reveal something.

Apart from that, only other thing I can think of is something in the dizzy
causing the spark timing to be off for that a particular cylinder. Can't think
what would do it for just one cylinder though. 100 psi isn't stellar, but it
should still run. What kind of numbers are you getting from the other
cylinders?

 

[smlk31]

Thanks I'll pull the cover and check that out

 

[Janicholson]

A good idea. An endoscope (not expensive) is also able to look in the cylinder to see valve action and the piston. Search for one that can attach to a smart phone. Jim

 

[Janicholson]

A cracked or carbon traced distributor cap will do it. Jim

 

[smlk31]

Just was gifted it and one of my thoughts were to get new points wires and d cap. the guy that gave it to me said he changed the plight to see if he could get it to fire all 4 cylinders.
Thanks for the ideas!. Just started this project so it will be a learning experience.

 

[DanielW]

Also, make sure you have the plug wire
order correct. Someone else on here will
tell you for sure, but I'm pretty sure
the 600 and 800 series firing order is 1-
2-4-3, unlike the much more common 1-3-4-
2.

It's common to find tractors with the 1-
2-4-3 firing order with the 2 and 3 leads
swapped by someone who didn't realize
this: I've bought a couple of Fordsons
cheap because the PO did that and
couldn't figure out what was wrong.
They'll still (surprisingly) run like
that, but very poorly. I think the rotor
turns CCW in that dizzy (I could be
misremembering - crank with the cap off
to check). If I'm right, the leads should
go 1-2-4-3 in counter-clockwise order.

 

[smlk31]

(quoted from post at 16:06:29 11/27/23) Also, make sure you have the plug wire
order correct. Someone else on here will
tell you for sure, but I'm pretty sure
the 600 and 800 series firing order is 1-
2-4-3, unlike the much more common 1-3-4-
2.

It's common to find tractors with the 1-
2-4-3 firing order with the 2 and 3 leads
swapped by someone who didn't realize
this: I've bought a couple of Fordsons
cheap because the PO did that and
couldn't figure out what was wrong.
They'll still (surprisingly) run like
that, but very poorly. I think the rotor
turns CCW in that dizzy (I could be
misremembering - crank with the cap off
to check). If I'm right, the leads should
go 1-2-4-3 in counter-clockwise order.

Thanks! I will check that out. Just waiting for the service manual which may answers lots of questions I have

 

[rustred]

what do u mean by dead cylinder? you have compression and spark u say.

 

[smlk31]

(quoted from post at 17:50:18 11/27/23) what do u mean by dead cylinder? you have compression and spark u say.

It doesn't fire internally

 

[rustred]

try a different spark plug

 

[smlk31]

I did that two new ones both spark when grounded outside the cylinder.

 

[used red MN]

Hello sm welcome to YT! I am will add a second to
Skippers post on the vacuum leak. Spray starting fluid,
carb cleaner or direct an unlit propane torch toward
the mating area of the manifold and head. A change in
the engine sound would signify a vacuum leak. Of
course not discounting what the others are suggesting
either.

 

[rustred]

Yes, but did u screw then in the head and try them. Takes
more to fire the plugs under compression with fuel. And
what brand of plugs ? Why would u not try them in the
head? Plus youre saying hood spark, have you checked
and compared each spark at the dist. When running and
how far you can pull the wire out for each one. Then
check at the plug ends. Should be jumping 1 /4 inch gap
easily with a snap and blue spark.

 

[smlk31]

(quoted from post at 19:00:06 11/27/23) Hello sm welcome to YT! I am will add a second to
Skippers post on the vacuum leak. Spray starting fluid,
carb cleaner or direct an unlit propane torch toward
the mating area of the manifold and head. A change in
the engine sound would signify a vacuum leak. Of
course not discounting what the others are suggesting
either.

I'll give it a try, Thanks!