Cause of Vibration in my 68 M20C Ranger

[Chris 68 M20C Ranger]

If you are experiencing a vibration in your mooney like I was you need to read this. One day my plane went from flying perfect to a nagging vibration. I checked everything EVEN the sparkplugs. We removed, inspected, cleaned and tested the plugs they passed; we put them back in the plane. We bore scoped the cylinders, balanced the prop, inspected the intake manifold, mags, carb, EVERYTHING. Then we took a step back and reinspected the spark plugs.....one of them was a little dirtier than the rest...we further inspected the cylinder for sticking valves....then my mechanic was regapping the plugs and BINGO! The wire had a tiny crack in it almost impossible to see with the naked eye but was noticable because the wire was "wobbling" slightly when he regapped it. New plug.......NO vibration back to running like a clock! PERFECT! I hope this message helps others that are on the brink of madeness like I was trying to solve this problem. I even had a Mooney mechanice take a ride and fly it and he said it was normal vibration.....If you notice a change in your plane don't give up or think it's in your head. These planes will speak to you when something is wrong and my plane did..The connections I failed to make during run up were: one mag would drop 100RPM vs the other only 50RPM's. This was telling me it was ignition related and I failed to notice. I was asked what happens when I did a mag check and I said it was normal...lesson learned. I hope you all benefit from this..zoom in on the attached picture of the sparkplug you will see the crack.

[Hank]

That's not what the plugs in my 1970 Ranger look like . . . so they must be fine wires and I have Massives. Big center electrode with two prongs on the sides that lean in towards the center. The gap is easily tightened up with a small ring that screws onto the plug, but if I ever over-tighten the gap then I am hosed.

[Marauder]

Think of the potential damage if that fell off into the cylinder... Yikes!

[Chris 68 M20C Ranger]

Think of the potential damage if that fell off into the cylinder... Yikes!

It fell off in my hand...I was lucky..

[carusoam]

Chris, welcome aboard!

I'm with Hank. I didn't recognize the type of spark plug you have either.

I'm only familiar with the massive style. Check and make sure you have the proper plugs while you are at it???

Sorry to add to your workload.

Is that what the fine wire plugs really look like?

Best regards,

-a-

[scottfromiowa]

Finally a reason besides price not to switch to fine wire plugs...

[scottfromiowa]

It was really because of the three blade prop...

[triple8s]

I had a spark plug issue a while back and it took me awhile to figure out. At altittude and every once in a while maybe every 10 or 15 minutes the engine would miss ever so slightly just one ahem to break up the very smooth drone of the engine. The hiccup wouldnt replicate it self on the ground, run up was fine. The only time it would do it is after being in cruise for a bit and at altittude above maybe 8000 or so. I talked to a few people and my mechanice said it was a plug, I was convinced it was something else but after a mag check at 8500 ft at cruise (was very unnerving) it was confirmed which set of plugs (or wires or which mag) was the culprit. So I changed plugs and it was cured. The whole point of this is.......would the tiny little crack have shown up MORE at altittude? or no? Would the tiny cracked electrode have caused a hiccup in the thinner air? I like Chris believe these machinse will tell us long before we have a problem if we will listen to them and I read everything I can to try to learn as much as possible.

[N201MKTurbo]

Plugs don't care how high they are, but Mags do. You could have a weak mag that cannot fire the weak plug, but can fire the new plug with the proper gap. Every time I've had your symptoms, resetting the points and internal timing takes care of it.

[HartParr]

I had a cracked plug-it only shorted and caused an obvious miss at altitude, mechanic said the thinner air would let the short go to elsewhere. Also from this incident I learned that age of plugs is as important as total hours.

[llebhsoj]

Chris, I have these exact symptoms. All was well and then it started, that little vibration that everyone else says is normal. I only fly when I have to now because I know the vibration is not right and it makes me extremely uneasy.  After reading your post I told my mechanic to order me a set of plugs and again I have hope!  I'll let you know how it goes. Thanks 

[DAVIDWH]

That cracked plug is a red herring.

You really need fine wire plugs, Gami's and new motor mounts.

Just trying to help all I can.

 

[carusoam]

Welcome out into the open posting world, Josh.

There are so many things that can cause nasty feeling vibrations.  A simple loose seatbelt end out the door can be really scary sounding....

Best regards,

-maosurac- 

Edited March 19, 2017 by carusoam

[neilpilot]

15 minutes ago, DAVIDWH said:

That cracked plug is a red herring.

You really need fine wire plugs, Gami's and new motor mounts.

Just trying to help all I can.

 

Please tell me how to install Gamis in my 65C

[N201MKTurbo]

Just now, neilpilot said:

Please tell me how to install Gamis in my 65C

Simple, buy a set of GAMIs and install an IO-360 around them. Problem solved!

[DAVIDWH]

Or, you could special order.

[N201MKTurbo]

25 minutes ago, DAVIDWH said:

Or, you could special order.

You do realize an M20C does not have injectors.

[DAVIDWH]

You do realize an M20C does not have injectors?

 

This is really confusing to me.

Just checked the calendar and the year seems to be 2017.

 

Difficult to fathom planes are still flying with carburetors, carb. heat levers, carb. fires, flooding issues, rough idle,

surging, hard hot starts, engine cranks, (no start), hesitation, sputtering, poor economy, bad gaskets, secondary lockout,

gummed up with old gas, or as Gomer would say "She's clogged again". I could go on for several pages, but why bother.

Yea, I know a bit about carburetors, flew a Mooney Ranger for years, then just hung it up.

Surprising, it wasn't only the carb issues that frustrated me the most, it was the wide turning radius.

Al Mooney was drinking coffee on that one until "The aerelons won't turn the plane issue was fixed".

Now about those Gami's.

Where were we?

[Piloto]

On ‎6‎/‎14‎/‎2013 at 0:51 PM, Chris 68 M20C Ranger said:

It fell off in my hand...I was lucky..

That is why I use massive electrode plugs. I never felt confident about the wimpy fine wire electrodes. Tempest massive are very good.

José 

[neilpilot]

49 minutes ago, DAVIDWH said:

Difficult to fathom planes are still flying with carburetors, carb. heat levers, carb. fires, flooding issues, rough idle,

surging, hard hot starts, engine cranks, (no start), hesitation, sputtering, poor economy, bad gaskets, secondary lockout,

gummed up with old gas, or as Gomer would say "She's clogged again".

Where were we?

Owned a 64 M20E 1989-2012 (about 2000 hours), and experienced "flooding issues, rough idle, surging, hard hot starts, engine cranks, (no start), hesitation, sputtering".  Fought a fuel injection issue for several years, ended up having my fuel system rebuilt.  A couple of years later totaled the E due to an off-field landing,  NTSB determined a piece of a torn O-ring in the fuel servo had blocked fuel flow to all injectors.

Have owned a 65C since 2012, and so far we have not experienced any of the symptoms that you attribute to a carburetor.  Other than an increased fuel consumption of about 0.5 gal due to a carb, it's been great.

[Ratherbflying]

Make sure your mechanic knows the proper way to clean fine wire plugs. Treating them like massives could be the reason the plug was damaged.

http://www.tempestplus.com/Portals/0/PDFs/Sparkplug Cleaning The Right Way 061212.pdf

[Andy95W]

8 hours ago, neilpilot said:

Owned a 64 M20E 1989-2012 (about 2000 hours), and experienced "flooding issues, rough idle, surging, hard hot starts, engine cranks, (no start), hesitation, sputtering".  Fought a fuel injection issue for several years, ended up having my fuel system rebuilt.  A couple of years later totaled the E due to an off-field landing,  NTSB determined a piece of a torn O-ring in the fuel servo had blocked fuel flow to all injectors.

Have owned a 65C since 2012, and so far we have not experienced any of the symptoms that you attribute to a carburetor.  Other than an increased fuel consumption of about 0.5 gal due to a carb, it's been great.

I liked this post so much I thought it should be shown again.  People should be careful about denigrating the humble C.  It is the most prolific of the Mooney models.  If you add in the M20B and D (virtually the same airplane) the numbers aren't even close.

For me, I could afford a bigger, faster, more powerful Mooney. I fly a C because of its simplicity and reliability.