I got this engine in a used trainer I bought a couple weeks ago. Obviously it's a Fox design, (with a custom retrofitted Perry carb) but has no markings and the case appears to be tumbled and zinc plated. IIRC, didn't Fox make private label engines for Tower in the 70's?? Is this one of them?

Even has a Fox glow plug in it

Looks like maybe a home made adapter for the Perry carb?
Don't think it's plated just tumbled...

The 1st Tower engine was a Fox Eagle .60 Mk. 1
It had a bead blasted case, and a tumbled head, backplate and Perry carb adapter (cast )
I got one at their introductory price of $29.99 in IIRC 1976. I put it in a TF Contender and that was a nice combination.

I don't recall right off hand if Fox and Tower collaborated on any other engines during the 70's?

It's a Fox 40 as can be seen by the 40 on the mount lug. This was the way Fox marked the 40 and 45 because they used the same crankcase. And that's about my sum total of knowledge about Fox engines except I think these were called the Barn Door engines because of the enormous back plate .

The engine is definitely a Fox. Fox engines had the tall rear cover because it made it easier for them to machine the internal bypass ports in the case. That was how they implemented Schneurle porting when it became popular in the 1970's, and it allowed them to have lower production costs.

Fox also used that unique flat plate upon which they mounted their carburetors. Duke Fox believed it allowed a better seal.

<font size="4"> the tall rear cover because it made it easier for them to machine the internal bypass ports in the case

Actually it allowed them to cast some of the case bypasses.

Paul</font>

Casting bypasses in these engines was quite a hurtle in the early production years. Duke Fox was a genius when it came to over coming production difficulties such as this. Incidentally, Duke himself has told me that the flange for mounting the carbs on his engines was designed to eliminate crank case distortion.

The finish on this example is typical of the time for Fox engines. It wasn't any special edition or anything

I don't know about that, but you don't have to worry about o-rings going bad, or not pushing the carb in enough, nor crushing the base of the carb from overtightening. An altogether satisfacory method of fastening the carb, though its really not that big a deal either way.

Hemikiller,

It is the first series of Fox "banjo-back" schneurle 40s and 45s from about 1973 or 1974. This one is a 40, as is visible on the mount lug. It is a lapped-piston, plain-bearing engine - the BB versions came a bit later... These ran well, and Fox developed them further over several years, up to and including the current 46 and 50 BB "big case" schneurles. The shiny, tumbled casting was the finishing method Fox used for all engines in that era. Later 40 and 45 BB Schenurles had a nicer light, satiny bead either blasted or tumbled finish.

Fox eventually offered an adapter spigot for the Perry carbs, but the adapter on yours does NOT look like the Fox item. There wasn't anything wrong with the stock Fox carbs, it's just that they were different to set up than the ST MAGs, Perry's and OS air-bleed types. A few guys who couldn't be bothered to learn how to set the Fox carbs gave them a bad rep. As I said, they weren't as 'even a caveman can do it' simple as the other types, but worth the effort when you did.

Provided the engine has lived on enough castor oil in the fuel, if it has been run much, it should run great and last until you're tired of looking at it.

Thanks for all the input guys and Lou, thanks for the very detailed specifics. I have some of the later Fox engines and just had never seen one that did not say "Fox" on it somewhere, even though it was obvious that it was. The lack of designation is what made me think it was a private label deal.

The carb adapter is definitely a home-brew piece.

I mounted this up in my test stand and ran it on a MA 10X6 with Sig Champion 15% enriched with a splash of additional castor. I fired it off rich and gradually leaned it out to a couple clicks rich of full beep. I swear this is the loudest 40 2C I have owned. Swapped in an OS A3 plug and it idled and transitioned very nicely, carb is set one notch lean on idle. Did not get any tach readings as the battery took an inopportune time to croak. I'll be swapping on a correct carb in the future. As it runs so nice right now, the Perry can stay for a while.

I had a rear exhaust Fox engine given to me. The owner said he was sick of trying to tune carb. I plugged in a perry carb....instant darn good runner, so we put it on a float plane & flew off the lake. lots of fun Capt,n P.S. Even flew it off a river...with caution!!!

Hemi and Cpnjohn...

If you ever get a look at Fox's 25BB schneurle, you won't find any brand mark on that, either. And it doesn't even look like any Fox you've ever seen. VERY nice engine; plenty power, and even a more "acceptable" looking two-needle carb on the RC versions. If they were to switch it to ABC or (dream on) ceramic, and promote it with some notable names flying it, our economy would be dragged back to the black-ink side of the ledger overnight!

I have a Fox that looks almost exactly like this one except it is the BB ringed .45. The finish is exceptional. And it is one of the best running engines I have with the factory carb, I like it! Yes it does take a different approach to tuning, but once it is set it idles and transitions fantastic.