Just wondering if I can get any ideas of what to check before we start throwing money at parts. Its a 182 with a 470R, it has had a vibration that comes and goes. I figured it was just from a few new nicks I picked up over the summer but even with those smoothed out I can feel a noticeable shake after takeoff when I pull the prop and throttle back. At first I only felt it around 2400, but on the last flight it was still there at 2200 where it normally would have smoothed out.

It has 150snew slick 6310s, and new tempests on top and older champion finewires on bottom. 6 point egt doesn’t show anything out of the ordinary and all engine instruments in the green. Haven’t noticed a power loss.

Comp checks are all above 70 with one at 67. Switched mags in flight and on a full power climb no difference, pulled power and descended and was still there. Slow flight or cruise it’s still there. Went up to 5k ft and compared egts at full power and at 13” to check for induction leaks, egts remained close. Will toss in new plugs on bottom and check intake closer and check prop track. My mechanic is coming up in a few weeks but not excited that I haven’t found an issue for him to repair yet.

I found this thread pretty informative:

https://backcountrypilot.org/forum/pponk-troubles-19367

Last week I was troubled by a vibration in my 182 which I thought was coming from my engine (0-470R) or maybe the prop. Turns out, one of those little rubber button stops which my cowl flaps close against broke off. The vibration was quite profound. I was considering cancelling my trip up to the International Sea Plane Fly-in in Maine cause of it. I have a lot of time in this particular plane, so you'd think It would have taken me less than a week to figure it out, but it didn't.

Have you eliminated tires? Larger tires and wheels can vibrate on spring gear. I'm not sure what excites the tires on my 180 in flight, but sometimes they just start wiggling with no real correlation to a specific airspeed.

I'd have guessed mags, but even if they're new, and your plugs are new, that leaves the harness linking it all together. I only have one data point to reference, and that was a bad points and condenser in a Bendix mag that caused a shimmy-like vibe on an O-300. IIRC the Slick aren't serviceable that way.

Balance tube...maybe. I know the PPonk guys were struggling with that.

Make sure you check all your spark plugs with a meter even if they are new. Check the resistance, not just putting them on an expensive spark plug cleaner/tester but also with a multi meter. Champions fail frequently.

Kurt

well...for what its worth...best thing i did was change airplanes..also an R model...to the lycoming 540.... a lot less noise...more power..no oil burn...lots less vibration....
the continental 470 is a mediocre motor and is just kind of fair...especially when using it to do any short/soft stuff....they seem dependable enuff, just kind of rattle trap like...

Check your spinner backplate for cracks also. I had a spinner go wobbly on me once after takeoff and it was a prettty violent...thought a cylinder issue at first. The plastic bulkhead inside was tore up bad and the spinner backplate had rubbed a nice groove into my cowling.

Something fairly easy to check anyway...

I changed my bottom plugs to the extended ones to reduce fouling. The engine would run funny at times and cause vibrations. Some one told me that you should not run the two different type of plugs. I switched the tops to the extended ones and it runs smooth as silk.

Thanks for the replies. I cleaned and tested the champion fine wires and resistance tests were all over the place. From 25k ohm all the way up to 700k ohm. Plugs looked clean but ordered tempest fine wires to replace them. Also found a hose clamp working it’s way through my lower cowling. Seems like it helped a little.

One EGT is showing failure, but watching the gauge it fluctuates up and down 50* or so then after a few minutes says failure. Would a failing valve cause this, but wouldn’t it have shown up on comp test? It’s a new jpi probe that was replaced recently since the last one had the failure message.

A friend of mine has a 180 with a pponk, built by an engine shop other than Steve, that occasionally had a miss and vibration. New Melinium cylinders I think. He threw lots of money at it including a new engine mount with the large isolators. In the end they found that one of the inter valve springs was broken an a times would block the valve partly open. Might be worth a look if you don't find anything else.

Tim

bat443 wrote:A friend of mine has a 180 with a pponk, built by an engine shop other than Steve, that occasionally had a miss and vibration. New Melinium cylinders I think. He threw lots of money at it including a new engine mount with the large isolators. In the end they found that one of the inter valve springs was broken an a times would block the valve partly open. Might be worth a look if you don't find anything else.

Tim

I was going to suggest this Tim. I work on a Pponk that was built by Steve and it had a failed inner spring on one intake valve. Never showed up on the compression test. Only reason I found it was because I had to replace the crappy cork rocker cover gaskets that were leaking. I'd check the springs for sure.

David

Borescope the cylinders. Especially the 67PSI.

The prices are very affordable. Example:
https://www.amazon.com/USB-Borescope-Endoscope-Android-Inspection/dp/B074KXB3JM/ref=asc_df_B074KXB3JM/?tag=hyprod-20&linkCode=df0&hvadid=198103677721&hvpos=1o1&hvnetw=g&hvrand=17556375343568384414&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9032808&hvtargid=pla-371040107488&psc=1

I have a scope on the way, saw good reviews on this model so grabbed one. The egt that I saw fluctuating a bit was a ECI reman we swapped on at annual 50 hours ago. Will be the first one I check.

https://amzn.to/2x92546

alaskan9974 wrote:I have a scope on the way, saw good reviews on this model so grabbed one. The egt that I saw fluctuating a bit was a ECI reman we swapped on at annual 50 hours ago. Will be the first one I check.

Regarding purchase: Make sure the camera is adjustable for a 000-180 Degree View relative to the insertion. Some do not have the flexibility.