Better check those engine mounts...

[beeryboats]

I'm picking up my engine from the shop Saturday. I'm like an expecting father for the first time. I can't wait. So to keep busy tonight I though I would shop for new Lord mounts for the engine mounts. I thought the rubber may be getting old. I was shocked to see the rubber was the least of my worries. The inner bushing tube in the center of the mount is almost worn completely through. The mount bolts have huge washers to avoid an engine coming completely loose, but I could have a bad vibration once the bushing was gone.

I bought this Kitfox IV used and stored for 10 years. It has 175 hours per the logs, but the engine shop said the 582 may have had 1000 hours! So, I have no idea how long it took the mounts to look like this, but I'm going to take a bolt out every year to see what's going on.
Jay
P.S. I'm going to change the bolts too. Anyone have the bolt size handy?

[t j]

Thanks for the heads up. It is timely for me. I'm in the middle of doing a pretty extensive condition inspection. The engine is still off so I'll be able to check those bolts easily.

[beeryboats]

Now I'm having a hard time figuring out what mount I need to buy. The one in the LEAF catalog looks right, but it is not thick enough. I need to get the spec sheets from LORD and see what I have.

[t j]

Do they look like these? This is a 503 so maybe not.

[beeryboats]

Yes, they look like the same mount.
Jay

[t j]

The Kitfox part number is 47001. The bolts are AN5-23.

The manual instructs to drill or ream the center bushing to .3125 (5/16) to fit the AN 5 bolt. You have to be careful not to heat the mount up so go slow and use some water to cool it while drilling.

I wonder if the builder damaged yours when drilling them? There shouldn't be any movement between the bolt and bushing if torqued down. An AN 5 bolt torque is 100-140 inch pounds.

[Av8r_Sed]

The Lord mounts on my 582 side mount are part 150PD-30.
Engineering Data:
http://rubberpartscatalog.com/home/products/vibration-control/plateform-mounts/plateform-mount-series/diamond/150PD-30

L.E.A.F. catalog listing:
http://store.leadingedgeairfoils.com/product_info.php?products_id=7593

[beeryboats]

Thanks for the info guys. TJ, I don't know what to think. I got the engine back today and at least the one other mount I looked at had the same off center wear. And what is really weird it that the wear is on the forward side of the hole. I would expect the thrust would be wearing the aft side. Anyway, I'm changing them all. And I appreciate the tip on reaming to size.
Jay

[beeryboats]

[quote=t j;46970]The Kitfox part number is 47001. The bolts are AN5-23.

Hi TJ. I measured my bolts and it looks like they are AN5-30 as the grip length is about 2-1/2". So I'm not too sure the Lord mount is correct.

[beeryboats]

The Lord mounts on my 582 side mount are part 150PD-30.
Engineering Data:
http://rubberpartscatalog.com/home/products/vibration-control/plateform-mounts/plateform-mount-series/diamond/150PD-30

L.E.A.F. catalog listing:
http://store.leadingedgeairfoils.com/product_info.php?products_id=7593

Thanks Paul. The specs on the LEAF mount show the center bushing length at .88". Mine is 1.12 " like the four hole one. The Rubber Parts listing looks correct, but it has a typo on the thickness. They show .12" equals 28mm!! At least the 28mm spec fits! Maybe that's they way to go. Should I see what Wick's has to offer?!?!

[beeryboats]

I found the mounts at Mid-Atlantic Rubber Products for $10.34 each. And I've got new hardware on order. Like I said earlier, my bolts measured to a -30 length. One thing I couldn't find were washers that are 5/16" ID and 1.75" OD. AN960 washers stop at 1-3/8" from what I've seen. I'd like to change them just to look nice, but where do they come from?
Thanks
Jay

[Av8r_Sed]

Jay, check out Lord part no. J-2049-3 for a snubbing washer to match your mount. It might be available from Mid Atlantic. Otherwise try:
http://rubberpartscatalog.com/home/products/vibration-control/metal-snubbing-washer/j-2049-3

[beeryboats]

Thanks Paul!

[t j]

The 1.74 X 5/16 washes that came with my kit are Kitfox part 91008. They are labeled "Lord Mount Snubber Washers".

[beeryboats]

The 1.74 X 5/16 washes that came with my kit are Kitfox part 91008. They are labeled "Lord Mount Snubber Washers".

Thanks, I'll order tomorrow. I just got the hardware tonight.

[beeryboats]

Ok guys. It looks like the center bushing is hardened steel. How in the heck did all you mod. IV Rotax builders grind through to make the center 5/16"? Or did they come that way from Kitfox? I used a new drill bit and just started to make a dimple in the darn thing. But you can't really push down hard with the drill press as the rubber starts to give. I was thinking of backing it up with a piece of wood. But I don't hold much hope that it will work.
Jay

[Av8r_Sed]

You just have to work up to it using increasing size bits and finish it off with a chucking reamer to acheive a tight fit. That's what the manual indicated circa '91.

[beeryboats]

Ah! Ok, that's the info I'm missing as the second owner. I'll gather all the drill bits between 1/4" and 5/16". It will be easier on the drills as well.
Thanks!

[Av8r_Sed]

Don't forget to borrow some letter size drills if they help the progression.

[Dusty]

I had trouble getting the right mounts( mine may have been drilled)
The solution was to go to smaller bolts and fit a sleeve in the engine bearer ,as drilling the mount wasn't practical as it appeared to be hardened

[Kurt.A]

Jay,
Snap On sells stellite 100 drill bits, might be worth the try if you are still having issues. If that won't drill it nothing will. Be carefully they are brittle.

[Av8r3400]

You would be very surprised at the hardness of material you can carefully drill with a cobalt alloy drill. They aren't that terribly expensive and can be readily found.

Grainger and McMaster stores have them. Even my local ACE Hardware has them.

A drill press and vise would b mandatory to keep everything in alignment.

[beeryboats]

Yes, alignment is foremost in my mind. My old ones are very off center. What I did was to mount a 1/4" drill in the press to align everything. I have the lord mount in the alum mount for the engine so I have something to grip. That kept it all lined up, then just go to the larger bit. But there was too much give in the rubber. I need to back the center bushing up with a hunk of wood. I'll try it again at lunch.
jay

[beeryboats]

I got two done at lunch. First one is "ok" but the second one is dead on center. I just had to take it in steps.