Engine tic and Cold Cylinder

[richcraig11]

So after sitting for about 5 years I built our CJ5 with the AMC 304 for my son. Before starting it I sprayed fogging oil down all cylinders a couple times and let it sit. Changed all the fluids and replaced the spark plugs. Got it all together and she fired right up but there is a ticking noise coming from the right side header. Decided to check the temperature on all the cylinders. They were all about 300 degrees except #2, it's about 120 degrees. I verified the spark plug was good and also the plug wire. She runs good and really smooth. I don't get it. If that cylinder was not firing at all wouldn't it run rough?

 

[Lumpy Grits]

What's the compression of the cyl?
Switch plug wire and plug.
LG

 

[richcraig11]

I already swapped plugs and plug wires. Coldest cylinder was still #2. I don't have a compression gauge, that's on the agenda for tomorrow.

 

[Lumpy Grits]

Do a comp and leak-down test.
Pull the valve cover, make sure when the engine is run'n that ALL of the rockers are move'n.
LG

 

[richcraig11]

UPDATE - I pulled the valve cover this morning and both rocker arms on that cylinder are moving up and down along with the push rods and lifters. Going to get a compression tester now.

 

[richcraig11]

Update #2 - Just checked compression. Compression on bad cylinder is about 30psi. All other cylinders about 110 psi.

 

[mtnwhlr]

I bet you have a stuck valve or a collapsed lifter. Either way I see a head being pulled in your future.

 

[Lumpy Grits]

I bet you have a stuck valve or a collapsed lifter. Either way I see a head being pulled in your future.

YUP-Time to get your hands dirty.
Good luck and please keep us posted.
LG

 

[Manic Mechanic]

could be rings. when i lost compression in cly #4 my rings compressed into the piston and sealed themselves in. lucky for me it didnt score up the cylinder walls so all i had to was get a new piston and rings for it (i put new rings on all 6 just in case)