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Friends, I have a Pinz problem to solve and would appreciate other mind's thoughts - My poor Grunhilde's cyl#2 is not firing [or firing veeeeery intermittently.]

The ailment had a rapid-ish onset - about a month ago. 25% power loss was noticeable, but drivable.
She started running rough-ish particular on up hills when I usually gun it. Poor acceleration in general even on a flat streach.

Diagnosis - I removed the spark plug wires one at a time and found that there was no change when Cyl#2 was removed.

Things I did in the process of trying to figure this out ....
replaced/gapped the all plugs
replaced all the HT plug wires
Checked that there is spark on Cyl2 - visually looks good/same as others
Checked compression - 105 on Cyl2 Between 120 -110 on the others.

I have not looked at carburetion - but from the sound of the post-combustion popping in the exhaust, there is excess fuel not burning in cyl2 that is burning in the exhaust stream later.

Fuel shut off solenoid does click when removed/replaced. - its probably good?

Carbs were rebuilt last winter. Thanks Jim.

Any thoughts about possible causes or things to check would be appreciated.
Fuel - spark- air - what am I missing?

Thanks,
Maxf

Just for process of elimination I would swap out the distributor cap and rotor to see if there's any improvement. Possibly a hairline crack in the cap?

adjust the valves. Your popping may be a tight intake valve

Yes, check the valves, especially the problem #2. If they aren't opening fully then you would get good compression but no power. See if they seem to be opening as much as other cylinders when rotating the engine.

All good advice. And while you have the valve cover off, take a flashlight and check for a broken valve spring. Personally, I'd star with hooking up a vacuum gauge. (old school diagnostics).

Guys,
For the sake of eliminating the easy, I replaced the Dist Cap and rotor. This had no effect on the roughness.

As I was fiddling with the cables I am getting less sure it is specifically #2. When I try to drive it there is a strange super low power state until I can get her rev'ed up, then almost normal power, but it drops back into the low-power-missing mode. It almost feels like when I had water in the dist cap last year - but obviously a much different issue.

Comparing today's my one mile test drive to last weekends 5 mile test drive - it seems like it is getting worse?

Next step is dig into the valve adjustment and assessment. Thanks for the help.

Sticking distributor advance weights could give that same feeling. Maybe a WD-40 shower and a little back and forth might clear that up.

Good idea in the WD40 dist, but with the civilian dist. Conversion, I dont think I have such weights anymore?

Next stop valves....
How hard is replacing a valve spring? or better question... How is it done?
I took the valve cover off to look and it looks straight forward. I always need to ask though, are there any hidden gotchas lurking under there?

Thanks for the help. I gotta get her running for the Veterans Day Parade. I always drive the Veterans Guest House people and I'd hate to miss it.

The Civi distributor conversion only changes the cap and rotor; the shaft and mechanical advance weights remain the same.

Valve springs can be easily (?!) changed by fitting compressed air to the spark plug hole; air pressure holds the valves closed while the springs and keepers are removed/replaced. No need to disassemble the head. Warning: be certain that the piston is at its bottom of travel (or air pressure will cause the engine to turn!) and when it is at that position that both valves are naturally closed (although you can remove the rocker arms to allow both valves to close regardless of cam position).

Jimm391730 wrote:Valve springs can be easily (?!) changed by fitting compressed air to the spark plug hole; air pressure holds the valves closed while the springs and keepers are removed/replaced. No need to disassemble the head. Warning: be certain that the piston is at its bottom of travel (or air pressure will cause the engine to turn!) and when it is at that position that both valves are naturally closed (although you can remove the rocker arms to allow both valves to close regardless of cam position).

Good Tech Session topic for someone to post.

undysworld wrote:

Jimm391730 wrote:Valve springs can be easily (?!) changed by fitting compressed air to the spark plug hole; air pressure holds the valves closed while the springs and keepers are removed/replaced. No need to disassemble the head. Warning: be certain that the piston is at its bottom of travel (or air pressure will cause the engine to turn!) and when it is at that position that both valves are naturally closed (although you can remove the rocker arms to allow both valves to close regardless of cam position).

Good Tech Session topic for someone to post.

Or you can use the shade tree rope trick.

i.e. pull the spark plugs, with a piston at about bdc feed a bunch of nylon rope into the cylinder, turn thr crank by hand to bring the piston up to compress the rope in the cylinder t hold the valves in place.

The rope trick works if you dont have an air compressor, I've done ij both ways.

I learn something new everyday! Today I learned that you will be more comfortable working on valve springs in the shade of a tree.

Oh, yeah, and also a great way to prevent valves from falling into the cylinder when working on the springs (Thanks, Edzz). Frankly, I think this is an even better idea because with compressed air, if you bump the valve hard enough and it opens, the pressure leaks out, and the valve falls into the cylinder. The only good thing about this is that the hiss of escaping air drowns out the swearing...

And you'll still need something like this. http://www.amazon.com/Lisle-36050-Keepe ... B0012S61IO

Might as well do intake valve seals if you're going ro remove the valve springs.

This may not be the case but your problem reminds me of a similar problem when I was younger and put new wires into my Aro (Romanian). It had an odd firing order and I didn't get them back right. It would back out of the drive but couldn't climb the slightest hill.

This doesn't explain you initial problem but I did notice you changed the wires. Worth checking 1243 clockwise. It's been over 30 years so I can admit the mistake.

Good luck

Clive

Guys, good ideas.

Double checked. Firing order 1243 .yes

With help from a pinz friend, I did visual inspection of # 2 valve springs, dont look broken. So no need to replace them...right. that would be obvious...right.

We did find that the carb jet for #2 was clogged. Removed jets and blew them out. Now we see good dripping on acceleration. I am now back to the original problem - the loss of power under load remains?

We adjusted timing and she run (idles) good at about 23deg . Does that sound right for the pertronix civi conversion.? Wow that dist is sticky had to use a dowel and a mallet to rotate it.

Next thing is valve adjustment???
I am less confident it is just a problem with #2 and back to thinking of broader systemic issues to check.