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The rubber engine mount grommets (spacers) on my Jabiru 3300 engine are in need of replacement. Ii appears that replacing the two sets of spacers for the upper engine mount positions will be fairly easy. However, that does not appear to be true for the lower mount positions easy because the weight of the engine will prevent the engine from rotating (tilting) upward to install the grommets. Can someone please help me with a strategy for installing the lower grommets. Thanks in advance for your help/advice.
I've never had to change my rubber engine mount grommets, but it appears one could use an auto engine lift crane and a nylon strap to slightly lift the engine to take the weight off the lower mounts. Also, although one upper mount should easily hold the engine, it might not be a bad idea to use the same method to take up some of the engine weight when releasing one of the rubber upper engine mount grommets.
When I mounted my engine on my 750 STOL, I actually bolted the mount to the engine first and then lifted the whole assembly (I used a nylon strap and my compact tractor's front-end loader!) and bolted it to the firewall. This sequence was per the FWF instructions from Jabiru USA. Obviously, with all the wiring and plumbing involved with an already mounted engine, it does appear the only practical thing is to replace the rubbers with the engine remaining on the mount! The auto engine lift crane should give you fairly precise control over how much lifting and movement you need - if you don't have one or can't borrow one, it should be a fairly inexpensive rental item.
To compress the rubber grommets to allow enough bolt length to capture the nut, I modified a "crows foot" C-clamp (inexpensive item at Lowe's) like this:
You can see where I ground the lower jaws to grab behind one end of the rubber grommet.
BTW, my FWF kit included extra washers/spacers, Pete Krotje at Jab USA said if there is ever a slight amount of engine sag but the rubbers otherwise appear to be in good condition, you can insert extra washers/spacers to shim the lower mounts and raise the engine up and eliminate the sag and not have to replace the rubber. However, after 10+ years and 760 hours, my rubber grommets seem to be holding up just fine!
Sincere thanks John!