If it is that much of a pain, we have sets that are already machined. I never recommend anyone buy them over spending 3 minutes per side with a flap disc though.
Harmonic vibrations in Jeeps: A new theory (please read!)
- Thread starter psrivats
- Start date
5 minutes per side for me. I'm not as comfortable with the grinder as some.
Anyone have an improvement using a specific skid plate?
Original poster had info stating a heavier mass would change the resonant frequency.
In general mass effects resonance and increasing the mass would lower the natural frequency so am interested in the ones that have had noticeable improvements by changing the skid.
Original poster had info stating a heavier mass would change the resonant frequency.
In general mass effects resonance and increasing the mass would lower the natural frequency so am interested in the ones that have had noticeable improvements by changing the skid.
Yes, I had a noticeable improvement going with a thicker skid that also raised the tc an inch.
I put a UCF skid plate (1/4") and it made a noticeable difference for the better. Did not cure problem but it improved things for sure.
Has anyone tried a front driveshaft that was balanced at a higher RPM than we are typically balancing them to?
I did (balanced at 3k rpm IIRC) and it did not make a difference. @Bonescc can confirm the speed, not 100% sure, but I specifically requested it. I think @jeepndogs also tried it without success.
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No. I don't have a body lift. UCF sells versions for folks with and without a body lift.
No body lift needed. It was a Barnes 4x4 skid for a TJ.
https://www.barnes4wd.com/Jeep-TJ-Bolt-On-Skid-Plate_p_867.html
Gumbyguyvoe
New Member
I just changed my clutch and flywheel and now have a vibration at 2500 3000 rpms feels like a bad balance but that checks out ok. Also my pedal is really high like my clutch was worn out. Any ideas
jeepndogs
TJ Enthusiast
Yes,
The company I used has the capability to balance up to 10,000 rpm. I would have to find the paperwork but I believe it was actually balanced at around 5000. It did improve SLIGHTLY from the low speed balance job done by Tom Wood
I found these interesting series of videos from WeberAuto YouTube channel talking about different tools to measure NVH in vehicles. Fascinating to watch since they discuss advantages, disadvantages and typical uses. The videos are long (30min, one it them is an hour) but very informative.
@Mike_H @bobthetj03 you'll like these. @Bonescc for your reference if you ever need as much detail since you asked me
1. Intro and discussion on Reed Tachometer and Briggs and Stratton Sirometer that @jjvw talked about earlier in this thread.
2.EVA (electronic vibration analyzer)
3. MTS 4100
4/5. GM picoscope
@Mike_H @bobthetj03 you'll like these. @Bonescc for your reference if you ever need as much detail since you asked me
1. Intro and discussion on Reed Tachometer and Briggs and Stratton Sirometer that @jjvw talked about earlier in this thread.
2.EVA (electronic vibration analyzer)
3. MTS 4100
4/5. GM picoscope
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Update 5/8/19:
Although not related to "new theories" regarding harmonic vibrations, this might be helpful to someone who has not read about my particular vibration issue and how I resolved it.
I just completed a trip that gave me a great opportunity to observe changes in vibration in high and low speed conditions after switching to manual hubs. I can now confidently report that the vibrations that presented at 68 mph and up after I re-geared to 5.38 with the 42RLE, 241OR transfer case and 35" tires are completely gone after installing Yukon manual hubs.
I know that I already reported these observations, but that was before I had the front driveshaft and transfer case out to install Advance Adapters Rubi-Crawler reduction gears in the 42RLE and before I fine tuned the alignment. I have another 7-day trip coming up that will involve substantial time at 75 mph on the Interstate. I will report again if anything changes.
Although not related to "new theories" regarding harmonic vibrations, this might be helpful to someone who has not read about my particular vibration issue and how I resolved it.
I just completed a trip that gave me a great opportunity to observe changes in vibration in high and low speed conditions after switching to manual hubs. I can now confidently report that the vibrations that presented at 68 mph and up after I re-geared to 5.38 with the 42RLE, 241OR transfer case and 35" tires are completely gone after installing Yukon manual hubs.
I know that I already reported these observations, but that was before I had the front driveshaft and transfer case out to install Advance Adapters Rubi-Crawler reduction gears in the 42RLE and before I fine tuned the alignment. I have another 7-day trip coming up that will involve substantial time at 75 mph on the Interstate. I will report again if anything changes.