Thorp Air Command - T18.net

Thanks Bernie it helps when someone has had done the same job I'll look froward to your contact.

Thanks LANCE

I used the original type mounts for my O-290 (cost $19.50) . http://www.aircraftspruce.com/catalog/e ... shings.php

Dan honed 4 nice aluminum bushings for me which made using these mount bushings work perfectly.

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Dean Cuke
Visalia, California
N772DM
KVIS

I saw those Dean how are they holding up for you and how long have they been on?

Thanks Lance

They are holding up just fine. They have been installed for 2 years with about 120 hours of fly time. NO signs of wear yet. Easy install, no sag, and a great price. I have no regrets installing them. Especially after pricing the lord mounts. lol

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Dean Cuke
Visalia, California
N772DM
KVIS

Remember, the isolators as shown in the pix, must have a steel bushing inside of them. This bushing bottoms out when the preload reaches the right dimension. Just snug is the right torque.

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Bob Highley
N711SH
SN 835
KLAL

Thanks bob will do

I did one at a time on mine a few years ago. Start with the top as they are the hardest. The last one will give you fits, but it will go.
Cubes

Thanks for the tip cubes I was going to start with the bottom , knowledge is king

lance

I checked and part # 08-03600 are the correct mounts. They are a dynafocal type mount, but on the 290 they are not used in a typical dynafocal fashion. The mount on the 290 is flat and not angled like a normal dynafocal engine. This is a good thing as far as changing mounts go, as it is easy to replace them. It shouldn't matter if you start on top or bottom as the mounts do not angle inward. Lift the engine slightly to take the weight off of the mounts, remove bolts and move the engine slightly forward (about 3/4" or so) and swap them out. Can also tip engine down and change top and tip up and change bottom. Tighten the bolt until the two halves of the mounts hit the bushing in the center (metal to metal).

Bernie Fried
N18XS

Thanks for getting back to me Bernie and for the info appreciate it.

Thanks Lance

Update, used a/c spruce 08-03500 which are J-7402-5 the 08-03600 that Bernie used were not available backordered , they were about half the price of the ones I used but were available thanks all who responded.

I have a 290 also, and am looking to replace the original Lord J-7401-3 mounts. From reading this thread and talking to Bernie at Kentucky Dam and Bill Williams a few minutes ago, is the cheaper aerobatic 08-03600 part a good replacement for the Lord J-7401-3 mount? It's half the price. This is what I know so far:
* The replacement mount for the discontinued Lord J-7401-3 is the Lord J-7402-5
* Aircraft Spruce has a part number 08-03500 that is the J-7402-5 for $449 for a set of 4 pair
that part number is here: http://www.aircraftspruce.com/catalog/e ... kkey=30619
* However, Aircraft Spruce has another part, 08-03600 that appears to be the same as the 08-03500 but beefed up for aerobatics - but at roughly HALF the price for $247 for a set of 4 pair. Aircraft Spruce says, " it is the same style as homebuilt type but inner core has been “beefed up” and elastomers added to encapsulate the spacer. 2" Diameter."
That beefed up part is here: http://www.aircraftspruce.com/catalog/e ... afocal.php
* I think I read that Bernie used this latter 08-03600 part when he replaced his mounts.

John Twigg
N12055

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John Twigg N12055 SN.79 Pittsburgh, PA (KFWQ)

Guys,

I used the 08-03600 mounts about 4 years ago and there does not seem to be any drooping since. I have an IO-320 with C/S prop and I thought the stiffer ones would be better to support the extra prop weight.

regards,

Jim

This forum and its members are really helpful. Glad to hear that Jim likes his. I went ahead and bought the 08-03600's after chatting with Bernie about his and getting assurances from Aircraft Spruce that I could return them if they didn't fit for me. Anyway, they look great and match dimensionally. And, they are beefier and $200 cheaper to boot. The 4130 steel tube supplied with each pair appears that it may be a bit short, so maybe I'll use the existing tubes. I'll know when I see the old tubes and compare lengths.

My engine doesn't have a lift ring, so some buddies and I are going to make up a six for our chapter. We took one guy's lift ring and measured it. It is 5.75" long (when straightened out) and 0.1875" thick and 0.625" wide. We didn't want to get into cutting bar stock or sheet, so I found a site, http://www.metalsonline.com, that has an incredible amount of sizes and will cut the metal to your specifications. The total came to $20.87 for everything to make our six rings. Metal = $9.92. Cut Fee = $6.00. Shipping = $6.95. Taxes = $0.00.
I expect that we'll have to heat-treat after bending this bar stock. Several of us are meeting at the Chapter this coming Monday night to make them up.

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John Twigg N12055 SN.79 Pittsburgh, PA (KFWQ)

If your material is the same thickness as a standard Lycoming lift ring, mild steel should be plenty strong, John... you shouldn't have to heat-treat anything. Hell, the case-half bolts are basically hardware store grade-3 bolts on a Lyc anyway, and the engine probably weighs less than 300 lbs. That's just my opinion - others may want to chime in with a different view.

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John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE