National Aeronca Association Bulletin Board

I just talked to Roger at Wag Aero this morning regarding the poor quality of engine mount bushings that are apparently be furnished by Superior. He has been in contact with the manufacturer, but their contention is that they haven't changed the composition of the bushings and, of course, he is stuck between a "rock and a hard place". I don't think he knows where to go at this point. Anyway, I ordered a new set of bushings that are supposed to be manufactured by Continental rather than Superior (not sure about that). Maybe that's the answer to our engine mount problems.........if they work any better, I'll let the membership know. The ones I have in the Champ right now are pretty well 'beat out' and have only been in there a few years.

I'd be interested in anyone else who has had success or short mount bushing life in the past few years. You all are probably sick of me beating this subject to death, but it seems we should get more than a year or two out of our engine mount bushings (and they 'ain't' that much fun to change ).

Mike

I have had good luck with the wag-aero ones, there are cosmetic cracks
that show up in the first year but the bushing hole for the bolt and the
taper surfaces seen to hold up for many many years. Last set I changed
were in for 900 hrs of flight time and the mounting of engine was still good.

Many people change them when they are not really bad just the part
sticking out has small cracks. Also you do not want to over tighten them.

I have got some that are as hard as a rock.

Mikek

I've always torqued them to specs (65-80 inch pounds). When tightening, it does seem tight (to my way of feeling) but that shouldn't cause cracks to appear. I agree when you remove them, the taper and the bolt holes are intact, but if nothing else it looks like h---. Mine has a piece of rubber hanging off one now . Guess I don't understand why the old rubber bushings lasted forever and didn't seem to crack (also seemed to fit better).

When I install the new bushings (if it ever warms up) I'm going to play around with different tensions and see how that works out.

I've heard it said that if you can find a old set (new old stock) from a few years ago the cracking is not a problem, but I've never been able to prove it as I've never found an 'old' set.

To be continued......................send me your thoughts.......... .

Mike: Since the hard as a rock is the only ones that work as they should and last, it's my first choice. If you can't torque these things to what the book calls for, they will be crap, plain and simple. The hard ones bearly expand at 80 inch lbs, but the Superiors will not even make 60 showing huge head expansion,and with-out sufficiant cone compression to keep the two lower mounts from bottoming out to almost metal to metal in no time at all. I put in two sets within a month of Superiors and then ordered a set from Wag. They are Superiors so I did not even use them even though I specified ones from SAR stock. Went looking for NOS hard ones, and no problems since.
Ron

mikeberg/wi wrote:

I've heard it said that if you can find a old set (new old stock) from a few years ago the cracking is not a problem, but I've never been able to prove it as I've never found an 'old' set.

To be continued......................send me your thoughts.......... .

Well, Mike lets see if its true, will check the hanger I am sure I have a NOS set, so email your address off line if you want and will send a set of
the hard ones, for testing.

Mikek

Just did an annual on my chief last week. I last replaced the bushings, from Aircraft Spruce, just over a year ago. They look like hell already now around the edges. However, I'm leaving them alone. Last time I changed based on edge appearance, they were great on the interior. I'll wait until I see the engine begin to sag. Easy to see on a Chief with tight nose bowl/spinner clearance. roger

Even though the bushing tapers look good, look closer at the nipple where the bolt goes through. The bottoming out will occur in this area, in the middle of the two tapers. New , there is less than 1/8 inch separation between the bolt and the center of the two tapers in the case. This is where I had my problems. The tapers is what keeps this area somewhat centered. If the tapers in the bushing are too soft, or not compressed enough...............well I think you got the picture.
I personally feel that since they will never be a safety issue, just a pain in the butt. It's oviously good for sales, so I doubt anything will ever be done about them.
Ron