Author Topic: Help? What Fox Engine Is This? (Read 1154 times)

Jim Carter · « **on:** September 24, 2018, 03:28:18 PM »

Greetings guys, please, can anyone identify this Fox engine? Other than the embossed name "Fox" on the left side of the engine and the front of the carb, there are no other marking and I can't tell if it's a .40 or a .45 size. I sure would appreciate any help.

Jim Carter

GERALD WIMMER · « **Reply #1 on:** September 25, 2018, 04:49:57 AM »

Hello Jim
The motor is a post 1980 large B frame Fox probably a 45 as the 40 was normally stamped as such on the lugs and latter had a stamp on the bypass. The carb is the series X twin needle and a control line venturi is still available from MECOA l. The 40, 45 and 50 had the same stroke and only the bore size differs. A good powerful, well made engine in my opinion . For some reviews and tests see:
http://sceptreflight.com/
Regards Gerald

Jim Mynes · « **Reply #2 on:** September 25, 2018, 05:59:53 AM »

Measure it!
Radius squared x 3.14159 x stroke will tell you the displacement.

GallopingGhostler · « **Reply #3 on:** September 25, 2018, 09:23:00 AM »

Jim Carter, probably the simplest way to tell is to remove the head and measure the bore. If you have say a 6" vernier caliper (I bought one 10 years ago for under $50, accuracy around +/- 0.001 inch) will make it easy. Other way is to use a ruler, measure in mm and convert to inch. The stroke for the .40 is slightly less at 0.715 in. The stroke for the .45, .46 and .50 are the same at 0.790 in. The bores are all different, which should help to nail it down.

http://sceptreflight.com/Model%20Engine%20Tests/FOX%2040BBRC%20Series%206.html
Fox .40 BB RC: Bore 0.840 in, Stroke 0.715 in

http://sceptreflight.com/Model%20Engine%20Tests/Fox%2045%20BBRC.html
Fox .45 BB RC: Bore 0.850 in, Stroke 0.790 in

http://sceptreflight.com/Model%20Engine%20Tests/FOX%2046%20BB%20ABC.html
Fox .46 BB ABC: Bore 0.866 in, Stroke 0.792 in

http://sceptreflight.com/Model%20Engine%20Tests/Fox%2050BBRC.html
Fox .50 BB RC: Bore 0.907 in, Stroke 0.790 in

bobsrc · « **Reply #4 on:** September 25, 2018, 11:29:01 AM »

You don't have to take the engine apart, just take the muffler off and look in the exhaust port with the piston at bdc. The 40 has normal looking oval shaped bypass ports to the front and rear of the liner while the 45 has a pair of angled slot type main bypass ports front and back. Good luck,

Jim Carter · « **Reply #5 on:** September 25, 2018, 11:35:34 AM »

Guys, thank you, thank you, thank you! That's just the information I needed! You guys are super!!

Bob, you were right on the money! Looks like I'm holding a 45! Whoooo hoooo!

GERALD WIMMER · « **Reply #6 on:** September 25, 2018, 09:05:10 PM »

Hello
Looking at old adds I cannot see the large 40B frame engine with the MKX carb or button head like yours only 45's seem to have come like that.
Note the 40B and 40 C (Compact based on the Combat) have a different bore and stroke (Bore 0.840 in, Stroke 0.715 in vs Bore 0.80 in, Stroke 0.790)
The B frame has the bolt on carb flange vs C frame square intake carb
Attached an old add for reference
Regards Gerald

Brett Buck · « **Reply #7 on:** September 25, 2018, 09:17:05 PM »

Quote from: Jim Carter on September 25, 2018, 11:35:34 AM

Guys, thank you, thank you, thank you! That's just the information I needed! You guys are super!! Bob, you were right on the money! Looks like I'm holding a 45! Whoooo hoooo!

It looks like the spot on the lug where the displacement is usually stamped was removed in whatever grievous harm was inflicted on the engine mount.

Brett

Author Topic: Help? What Fox Engine Is This? (Read 1154 times)

Jim Carter

Help? What Fox Engine Is This?

GERALD WIMMER

Re: Help? What Fox Engine Is This?

Jim Mynes

Re: Help? What Fox Engine Is This?

GallopingGhostler

Re: Help? What Fox Engine Is This?

bobsrc

Re: Help? What Fox Engine Is This?

Jim Carter

Re: Help? What Fox Engine Is This?

GERALD WIMMER

Re: Help? What Fox Engine Is This?

Brett Buck

Re: Help? What Fox Engine Is This?