Picked this up with a garage sale Zero

Says FOX on the carb, but no other marking whatsoever. I measured the bore and stroke and came up with .89cu" (so a 90?). The case is 2 piece with the second half on the back split right across the cylinder centerline. Will add another photo later (tear down)

Was gummed up bad, but turns nice now. Low speed needle was broken as well as the ring having fractures (came out in 3 pieces)

Anywhere to get parts for these? I didn's see them on the FOX Mfg site...

Thoughts?

You can get a ring from Frank Bowman

[email protected]
Frank C. Bowman
1211 N Allen Ave.
Farmington, NM 87401
505 327 0696

for new bearings http://www.bocabearings.com/

I don't know that they ever made a 90. They made a 78 and a 74

It is a Fox .74. You can get a ring from Fox as well. If you go with Frank Bowman, you may need to send the engine so he can custom fit it.

doesn't look like it was ever run?
Maybe just you cleaned it before the picture?

it looks like it has a few miles on it for sure.

the ring had a number of cracks in it and it came out in 3 pieces.

thanks for the info on the parts. I used a machinists ruler to measure the bore and stroke (Don't have my mic or calipers here) but I dont think it was as small as .74 or .78 based on the crude measurements....

I'll give Frank a call and go from there...

thanks again!

On the head with w8ye.

Bill

Doubt it.

Bill

you are going to need bearings too

Thanks.. Between how the bearings look (and now that it's loosened up) how they feel, it'll certainly need bearings.

I remeasured and then used the right formula (misplaced the brackets in the piR2xH the first time)

Came up with 0.53495552 using more accurate measurements and the right formula.

Would this be a .50 then? not sure if they made a .53 or .54. Cannot find a lot of info on their engines. Surprised I couldn't find any other marking than what was on the carb.

Calling FOX in the AM to see what they come up with.

Thanks,

you should find Fox to be very friendly and informative.

Paul,

I know Fox made a .60 and .74 in this configuration. Certainly it is not a .50 or .55...

Fox Mfg should be able to sort things out. If you don't feel a need to buy a bunch of new parts, consider a crock-pot/antifreeze soak to clear away the congealed castor. The ring, definitely, needs to be replaced if it is cracked and broken as you said. Unless the cylinder bore got scored by it, you may get off lucky.

Quote:

ORIGINAL: pmillerusa

...I measured the bore and stroke and came up with .89cu" (so a 90?).

Paul,


Fox never made an Eagle .90 engine...

How are you making your displacement calculations?


The right way is to measure the bore and divide it by two. Multiply the result by itself (square) and then to multiply it by π (Pi - 3.14159...) and again to multiply the result by the stroke (the movement of the piston from BDC to TDC - NOT the depth of the piston in the bore, when it is at BDC).

If, for example, an engine has a 1" bore and a 1" stroke... half of 1" is 0.5". Square that and you get 0.25". Multiply that by π and you get 0.7854", which when multiplied by a stroke dimension of 1", equals to a displacement of .7854 cubic inches...

The Fox .74 has a displacement of .736 cubic inches.

I think he did make a .90 or maybe larger. But I think it was a special built engine made for a governement drone, it may have been gas ignition as well.

Quote:

ORIGINAL: Sport_Pilot

I think he did make a .90, or maybe larger. But I think it was a special built engine made for a government drone, it may have been gas ignition as well.

Hugh,


But it was not an Eagle .90, which was never offered by Duke, or by the factory after he passed on.

Fox do offer larger spark ignition engines.


The photos Paul posted are no doubt of a Fox Eagle engine.

The bore and stroke for the .60 is .905 bore and .937 stroke, the bore and stroke for a .74 is 1.00 bore and .937 stroke. That appears to be an early .60.

Thanks all.

See my last post on the measurements and how I blew the calculations. Doing it right came up with ~.53

Picking up my Micrometer and Calipers from the brother in-law that borrowed them a while back tonight and will re-measure, but with a machinist ruler it’s .88” bore and stroke.

I spoke with Charles at Fox this morning and am sending him these photo's as well as these #’s and we’ll see what they come up with. He seemed to think it was an old .60 as well based on my descriptions.

So when you get the right tools, the job is alot easier... got my calipers back last night and confirmed the .60" size.

Bore .905", stroke .937" ring thickness .046"

Frank said he has the ring for $13.00 and I'll be following up with Charles at FOX later to get details on bearings or if they have a package "overhaul" deal...

thanks again for all the help.

What's the fun in a $99 Magnum when I can overhaul this american iron...?

Thanks,

Your engine uses a 6903 bearing in the rear which is $4.97 from RC Bearings

and it uses a R6-2RS in the front which is $3.97 from RC bearings

That is $9.94 plus shipping from RC Bearings
http://www.rc-bearings.com/catalog/a...b43f&x=11&y=10
http://www.rc-bearings.com/catalog/a...590112&x=8&y=4

both bearings from Boca Bearings come as a set #ENK-40 for $21.95 including shipping
http://www.bocabearings.com/main1.as...054&n=*ENK-040