Engine sag - can it be shimmed?
 

Subject pretty much says it all. I have about 200 hours on my RV-4 and have a plain vanilla Lycoming in it. There is a small sag now so that the spinner is about 1/4" lower than the top of the cowling. Can the engine be shimmed at the mounts to raise the spinner up a bit? I have dynafocal mount bushings. Any other suggestions?

Scott,
You could double up on the flat wood washer type spacer that is already between the engine and the lower mounts. Many certified aircraft have two to start with and many have different combinations to aim the engine along the proper thrust line....Of course you could always change the lower mounts, with new, to get the sag out but that would be my last consideration.
Good Luck,
Mahlon
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Yes, you can use the wide area washers like the ones provided with the mounts, and place them between the "ear" of the engine mount and the rubber puck. I did this trick on my RV-6 after about 200 hours and it brought the engine back into perfect alignment with the cowl.