Spark and Fuel But This Cylinder is On Break...Ideas?

[RonMele]

Hello Gang,

So I've been on here braggin about getting my 66 on the road...it's been fun to drive and it has drawn a lot of looks and several "mind if I take a picture"s...

On the way up a hill today the truck was very doggy...felt like it was missing pretty bad. Oh the flats, going fine. Fair amount of vibration in the hood. The truck is still in my break-in/get used to driving it stage so a lot of these sensations are new...but the truck was a bit of a dog yesterday as well...

I had changed the plugs this morning and by this afternoon noticed that the number 1 cylinder didn't seem to be firing...plug wet. Ran it with and without the plug wire attached...no change in sound, idle, etc.

Checked the plug...it fires fine outside the cylinder.

Brother (my Able Bodied Auto Assistant) thought that perhaps the E or I valve in this cylinder was not closing fully. Early in the project we had adjusted the lifters (and discovered several broken ones).

Our plan (next time we are working on the truck...I've got to get back to work!) is to follow the Ford Manual procedure for checking and adjusting the hydraulic lifters for this cylinder...

Is there anything else that would cause this cylinder to not fire? The engine was overhauled at some point before I got the truck though I am not sure how much it had been used it was parked, who built it, etc.

I've somewhat ruled out a blown head gasket since the #cylinder doesn't seem to be having any issue.
The truck doesn't burn a drop of oil (so I don't suspect bad rings).

But...open to any/all suggestions!

Thanks again guys (and gals),
Ron

[Casey 65]

Is there continuity from the distributer to the plug?

[slick4x4]

Simple things first... Did you put a new plug in it ?
Try another... It could be bad
Just because a plug fires outside of the cylinder
doesn't mean it will fire under compression
It's worth a try

[ROOSTER]

[quote="slick4x4"]Simple things first... Did you put a new plug in it ?
Try another... It could be bad
Just because a plug fires outside of the cylinder
doesn't mean it will fire under compression

Do a compression test. Won't fire without compression. Bet you find a low cylinder.

[Obsa]

Do a simple leak down test with that cylinder on TDC with both valves closed apply air pressure. (you can buy or make a airline with a sparkplug thread on one end and a quick connect to air compressor line on the other) The listen for air leaking. Air noise coming from the oil cap means bad rings. Air noise from the carb means bad intake valve. Air noise from the tailpipe means bad exhaust valve. The intake or exhaust noise could also be from improperly adjusted valves

[ROOSTER]

Do a simple leak down test with that cylinder on TDC with both valves closed apply air pressure. (you can buy or make a airline with a sparkplug thread on one end and a quick connect to air compressor line on the other) The listen for air leaking. Air noise coming from the oil cap means bad rings. Air noise from the carb means bad intake valve. Air noise from the tailpipe means bad exhaust valve. The intake or exhaust noise could also be from improperly adjusted valves

In order to do a test like that you would have to loosen the rockers. When you introduce air in the cylinder it will force the piston to the bottom and open the intake or exhaust valve depending on the stroke it is on.

[William-in-St George]

FE engine? Remove the rocker cover and pull all the spark plugs. Turn the engine over with the starter and observe the action of the rockers on Cylinder #1. Unless the issue is obvious i.e. bent push rod. The "broken lifters" comment is a bit concerning. You may have wiped a camshaft lobe. I hope not. JMHO!

[Toyz]

Do a simple leak down test with that cylinder on TDC with both valves closed apply air pressure. (you can buy or make a airline with a sparkplug thread on one end and a quick connect to air compressor line on the other) The listen for air leaking. Air noise coming from the oil cap means bad rings. Air noise from the carb means bad intake valve. Air noise from the tailpipe means bad exhaust valve. The intake or exhaust noise could also be from improperly adjusted valves

In order to do a test like that you would have to loosen the rockers. When you introduce air in the cylinder it will force the piston to the bottom and open the intake or exhaust valve depending on the stroke it is on.[/quote
Key words here; "depending on which stroke it is on".
NOT loosening the rockers in advance gives you the chance to determine ( or rule out), a lash problem, IMO.
Paul

[Limestone66]

FE engine? Remove the rocker cover and pull all the spark plugs. Turn the engine over with the starter and observe the action of the rockers on Cylinder #1. Unless the issue is obvious i.e. bent push rod. The "broken lifters" comment is a bit concerning. You may have wiped a camshaft lobe. I hope not. JMHO!

Sounds like the problem i had with my old truck, except i had three of 'em. x2, Pull the cover, spin it over and look. Could be adjusted improperly {hopefully} or worse. Bad valve. .........Good luck.

[RonMele]

Thanks guys. Have done some of this (new plug, wire, etc.) but not the test. Heck, I ran out of time and wasn't able to take the cover off and have a look...that's on "the list" for the next truck work day! Appreciate all the help.

[Obsa]

If the piston in the cylinder you are checking is on TDC the air pressure will NOT force the piston down. If you are sloppy about getting it on TDC yes it will move. I been doing this type of low buck leakdown test since the mid 70s

[R Pope]

Spin it over with your finger plugging the spark plug hole. If it has enough compression to blow past your finger, there is enough compression to fire.

[RonMele]

Finally got back to the truck (it does not live where I live) and did a compression check. Sure enough...ZERO compression on the #1 cylinder. We followed the book procedure for adjusting the lifters and voila! Now #1 has the same compression as the rest of his siblings. Tomorrow morning we'll put it back together and see how the truck runs on all 6 cylinders. Weather looks good so I'll be brining it to a local tractor show (brother and nephew have a couple old farm tractors they'll bring) on Saturday and then a car and antique show on Sunday. But the best part? Driving the truck!

[Limestone66]

Thats great news. Glad it wasnt any worse.