mikejr718 Posted February 24, 2019 Report Share Posted February 24, 2019 Have been trying to chase down a vibration in my 1975 m20c. Is fine on the ground but vibration starts after taking off and climbing. Goes away when power is pulled back to decend Have dynamically balanced prop(3 blade Hartzell) Noticed the engine baffles are starting to rub on the battery box. Thinking the engine mounts have allowed the engine to sag and rub. Mounts are old, 20 years if log book is correct. Planning on replacing mounts and shimming engine to match cowl. Can I expect envy improvement in vibration level? Quote Link to comment Share on other sites More sharing options...
Guest Posted February 24, 2019 Report Share Posted February 24, 2019 You’re on the right track, there should be no contact between the moving engine parts and fixed airframe parts. Worn and improperly installed mounts are a good starting point. Clarence Quote Link to comment Share on other sites More sharing options...
Hank Posted February 24, 2019 Report Share Posted February 24, 2019 My doghouse is at least 1/2" from the battery box. You don't want to have to replace either one. I've heard that battery boxes run 2AMU. Quote Link to comment Share on other sites More sharing options...
carusoam Posted February 24, 2019 Report Share Posted February 24, 2019 My M20C... Engine vibration was caused by a broken engine mount and the resultant sagging... the change in vibration was subtle, but significant... Noticeable but hard to describe... Bubbles in the magnetic compass were shaking around... The engine sag depended on the day... one time it sagged noticeably, the next barely noticeable... There are only four bolts holding the engine in place... mine was down to three... OHing the engine mount is pretty easy... PP thoughts only, not a mechanic... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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