Race,

Funny thing about those engines... I had them all out of the boxes looking at them the other night and was startled to find they appear identical in size and have no identifying markings or features! Which one goes in which box? [X(] I'm pretty sure I have the 36 back in its box, but I might have to pop off the heads and do a bore measurement to be sure -- IF the bore is different; maybe it's just the stroke?

As for fuel, I have some genuine Fox 10% nitro 20% castor. Magnum recommends a 20% all-castor fuel to break in its four-strokes and I had new .52 and 1.20 Magnum four-strokes to run in so I ordered some. I swear the .52 I broke in on this fuel broke in faster and smoother than another .52 I broke in on my usual 80/20 synth/castor blend. The nitro content may be a little high for the Fox two-strokes, but I wanted 10% for the four-strokes.

I know about the heavenly lube smells... I used to roadrace a two-stroke motorcycle in WERA in the '80s. The exhaust smells at the flying field remind me of the old days at the track. The lubes I buy to add to my store-bought fuel are Klotz Super Techniplate (KL-100 synth/castor blend) and BeNOL castor... good stuff.

Good flying,
desmobob

Desmobob,

In 1983, Fox made .29s, .36s, and.40s, all in the same basic configuration. These were the Series 5 engines. The 36s had NO markings. The 29s were stamped "29" on the top of the left mounting lug. The 40s were stamped "40" on top of the left mounting lug.

As you suspected, only the bores were different. They were 29-.730", 36-.800", 40-.840".

Fox called these BB engines, but in fact, they only had a REAR ball bearing, the front end was bushed.

Later on in 1987, Fox came out with a twin BB engine.

The pictures show the 1983 engine and the 1987 engines. You can clearly see the large front BB housing on the 1987 engine. The engines came in both RC and control line (no throttle) styles.

Sometimes, the 1983 36 control line versions are called the Mark V Combat Special, but they really weren't very racy!

Incidentally, the 1983 Fox 29s were the last 29s Fox made.

Bob, I have three fourstrokes that I broke in on Fox 15% nitro fuel with 20% castor and then ran them for two seasons on it before I became "educated" on the ills of using castor in a fourstroke. They are an Enya .46 MKII, a high compression Saito 1.50 and a really high compression Saito .80. If you wrap your thumb and index finger around the prop driver and twist them they do not leak compression at all. They have seriously uglied up mufflers but run strong. Their exhaust valves did not load up with crud they became gold colored and stayed that way but no problem. The 1.50 is black with chrome rocker covers, maybe the gold exhaust valve makes it a Golden Knight engine.

GWILLIE,

Thanks very much for the information. I got my three new Foxes back out and looked at the mounting lugs. The two engines that were in the 40BBRC boxes had a "40" stamped on the lug, while the one I had in the 36BBRC box had no marking at all. Must be I had them in the right homes.

Maybe Ill find a muffler or two at the WRAM Show tomorrow and I can try running one of the .40s soon.

Thanks again for the Fox information!

Good flying,
desmobob

Desmobob,

The tilt down and tilt up mufflers that Fox currently sells for the 40 bushing, 40BB or 40 delux will fit your 40 or 36. Look for tilt down #90237 or 9237, tilt up #90236 or 9236.