Excessive vibration

[mshac]

Another thought for you -

Use one of those cheap IR temp pistols to check the cylinders and exhaust pipes. You know the kind, they usually have a red laser pointer on them. Maybe $25, most likely less. We'll call it the Poor Man's Engine Analyzer!

You can take some live readings while the engine is running. More than any particular temp, you're looking for DIFFERENCES between the cylinders.

Measure cylinder #2 (the suspect) with both mags AND L/R ONLY! You want three sets of data. Knowing what happens on L/R mag only is very helpful in diagnosis.

Measure the exhaust temp about 1" below the cylinder head. Measure the spark plugs, measure the heads. You'll quickly notice any cylinder that's "out of whack", and you'll have a good basis for determining the cause.

EDIT: Here is one for under $25:
Etekcity Lasergrip 1080 Non-Contact Digital Laser Infrared Thermometer Temperature Gun -58℉~1022℉ (-50℃～550℃), Yellow and Black
by Amazon.com
Learn more: https://smile.amazon.com/dp/B00DMI63..._kmq7FbZP5ZR8C

[Learjetter]

Thanks guys! I’ll do as suggested.

Mshac— the airplane came to me this way, which is why my priority 1 is an EDM-960 or similar.

[wslade2]

Ditto. Mine came without engine monitor.

I’m in the process of installing engine monitor. Reason: had some cylinder work, mag work and Fuel system work done. On run up engine very shaky. We kept going over and over everything we did and couldn’t find a fault....until I leaned over and burned one hand while the other rested comfortably on neighboring cylinder. Problem was cold cylinder. Long story short. There was the smallest amount of grit plugging injector. Definitely work on your cold spark plug problem. I could have saved a couple weeks if I had installed engine monitor from getgo.

Also, 1 inch of movement seems like a lot. Look carefully to see if you engine is sagging. Motor mounts (rubber cushions) may be shot. I know cause just had that problem too.

Couple years back, had similar problem with my new to me 182 at take off. Wasn’t terrible but could feel it. It was everything together: bad mounts, 1 weak mag, high resistance plug, one cylinder had induction leak (caught those last three via engine monitor) and topped it off with dynamic balance. Wah-la! Problem solved.

[JAG]

Everyone has added great advice on digging further into #2 cylinder - so I won't dogpile on there.

Just a couple more thoughts on rough running/vibration. If your engine ignition, timing and mixture is all correct, you should not have any vibration. I can idle my rear engine at 675 RPM, and there is no vibration or beer spilling. Getting the engine set up right on the above items is important. A good A&P should be able to sort it quickly by starting with the simple things first; magneto timing, spark plug lead testing, spark plug testing (I would just replace with new ones...), cleaning and testing the injectors, checking for induction leaks, then performing the proper checks on the fuel system (SID97-3G).
Jeff