Any guesses about a high vibration at idle? My 2005 R50 has a CVT transmission and the idle vibration is no different in drive and neutral. It is drivable but this vibration is annoying (and potentially harmful).

1. I replaced the hydraulic motor mount (twice).
2. I replaced the transmission motor mount
3. Replaced the lower dogbone motor mount.
4. Replaced the exhaust hanger mounts (twice)
5. Verified nothing was contacting the engine/transmission.
6. Shoved and made clearance around some tight AC freon hoses.
7. Flushed the fuel lines and cleaned the injectors (twice).
8. Replaced the spark plugs (looked good).

FWIW, the are no check engine (SES) lights

 

Out of curiosity, I just did a compression check.

1. 163 psi
2. 160 psi
3. 153 psi
4. 135 psi (140 after adding a little oil)

The plugs are OEM and look clean.

Thanks,
Peter

 

That could be your vibration problem.

 

Ugh. Yes. I may have answered my own question.

Rule of thumb “compression should be within 10%”

I think I need a valve job.

Peter

 

Curiously, I did an Italian tuneup (redline acceleration in a few gears) and number four came up to 145 psi (and it runs smoother).

 

Not likely vibrating due to compression as the engine vibrates even when coasting.

Is there a vibration damper anywhere on an R50?

The vibration is much reduced outside the motor mounts; however, there is considerable vibration on the front frame rails behind the bumper. This R50 Mini was totaled and repaired before I purchased it with a SALVAGE title. I’m concerned that a vibration reduction item was removed and I don’t know it because I’m unaware of what might be normally there.

I’m thinking that what is missing is a vibration reduction brace, and passive dampener (mass on a spring), and engine component, or something similar.

Please help,
Peter

 

There are three mounts. Replace them all.

1 on top right engine
2 on trans, left side under air filter
3 back bottom of engine to frame

 

Yes, on the Cooper, there is a crankshaft vibration damper. I suggest you jack up the front of the vehicle, remove the front right side wheel and wheel well liner, then start the car and observe the damper and the serpentine belt. If you have one, attach a timing light and see what's going on in slow motion.

 

In my case, idle vibration was caused by a third party top left engine mount (the hydraulic one). It was new, btw, but not OEM. Once I replaced it to OEM (Corteco) - vibration is gone from the cabin (sure, motor still vibrates, but it seems normal for these cars).

 

I have replaced all three motor mounts and all are factory OEM. Actually, I’ve replaced the hydraulic mount twice in six months as I thought I installed it wrong.

I’ll try the timing light thing although I don’t know if I still have a working timing light. It has been decades since I had a car that used them.

Peter

 

This is how I was testing my vibration level.
Before replacing the mount: After:

 

Ha ha! Great. I can mount an accelerometer to the engine and get numbers BUT I can much more easily put a cup of water on the engine and see how it compares to the video.

Thanks,
Peter

BTW, I’ll check to see who made my hydraulic mount. However, the frame vibration seems to be very mild there as though the vibration is circumventing it somehow.

Thank you,
Peter

 

Have you checked that your crank pulley isn't separating ?

 

FWIW, Crank pulley is okay.

 

Great test method!
Before: Valve Cover
After: Hood
Did you notice any difference just because you moved it? I’m definitely going to try this once I get the bumper back on.

 

I had to replace the hydraulic mount on hers twice. Vibration was *awful* - couldn't even hear the engine over the din of the vibration. Ordered a Lemforder mount from one of the vendors here. Didn't do a damn thing. Was almost worse after replacing. So I went through every mounting point - replaced the bottom one, added some poly bushings to others. Then I carefully looked at the the hydraulic one I had installed like 6 or so months prior - it was very saggy and sad looking. So we ordered a second one. Never heard back on that **** part that a very active vendor on these forums sent us - even after contacting said vendor about said **** part. The second replacement was the charm. All of the vibration was gone and I could finally hear the supercharger on her car.

 

Sadly, I’ve replaced the hydraulic mount twice already but both times it was with a Beck Arnley so if theirs is bad, Ive done it twice. I’ve now burned $1,000 in parts and 1000 hours in labor so I’m getting tired of throwing money at it.

Peter

PS. With the AC on, it idles at 1050prm and the ignition advance is ~3 degrees and the vacuum is about 13”Hg. Things improve a little when I turn off the AC (850rpm, 16”Hg, 4 degrees and less vibration).

 

Curious new bit of info on this vibration

The hydraulic motor mount feels dead quiet with the engine idling (even though the engine vibrates considerably). However, there is noticeable vibration on the front frame rail down near the bumper.

1. Could the engine be touching the frame somewhere? (I've searched and not found anything but it is very tight down there).
2. Might there be a resonance that amplifies the vibration out at the bumper mount? (A dynamic spring-mass-damper vibration problem).

Peter

 

I checked my car today while I had it out replacing wheel studs. It idles between ~800-830 rpm both with and without the AC on. I believe vacuum was around 19 in Hg with the AC off and something like 17 in Hg with the AC on, but I didn't write it down at the time. I checked everything with coolant temp at ~195°F.

 

Wow. Thank you. Those are very interesting numbers.

1. Why would my idle go so high with AC engaged even though it is cold so the compressor load would be low.
2. Why is my idle vacuum so low???

Interesting,
Peter

 

FWIW, the vibration is getting worse and makes the car rattle at idle, especially when cold. I have loosened and retightened all of the front subframe bolts to make sure they weren’t in a bind and listened to it on a lift with the engine running (in drive, neutral, and reverse).

I even went to a salvage yard (LKQ) and looked at a few cars for missing dampers, etc. I didn't see anything except maybe the strange dual tube front of the frame rails where the bumper attaches. Maybe that is some sort of passive damper system.

I am waiting for it to explode or the weather to get better so I can do the front wheel/harmonic balancer test. My son gave me a 6 microphone cabled stethoscope from Harbor Freight for Christmas that is now waiting for better weather to try out.

But it is clearly getting worse,
Peter

 

>CVT automatic transmission

What about this elephant in the room. Wouldn't be the first time. Bunch of threads on this board turn up on a "CVT vibration" search. None of them seem to end well.

Other than that, would try running without the serpentine belt to see if anything rotating might be hanging up or getting ready to fail - AC compressor/clutch, alternator, idler etc. Then change out the harmonic balancer / dampener; probably would do that anyway.

Was thinking of getting one of these, interested to see what you think of it.

 

Waiting on better weather as it is nasty cold in my driveway.

Regarding the microphone thing, I haven’t used it but my son did and quickly found a grinding left rear brake caliper he originally thought was in the front of the car.

Peter