"Fox 35" which version is better??

Any info will be good info!

rv.

There are those who maintain all Fox 35s suck, but that they seem to do so equally. And who said quality control was/is an issue with Fox motors?

Unlike with the many and widely varied stories about certain runs of Cox TD 049s, I have never heard of a particular style or year of Fox 35 being demonstrably better or worse than your average piece.

As BigIron13 has noted, the newer quick-run-in piston/cylinder fit is a variable, one which I don't believe he cares for, presumably as the useful life of any given piston or liner is shortened somewhat, although I am not making a claim based upon personal experience.

As a personal matter, I use RSM tongue mufflers and so much prefer the later cases with muffler mounting lugs running clear to end of the exhaust port.

As a general observation, the within model variation is greater than between models. If you are a fan of inferential statistics, this means there has got to be a large difference between samples before you get a significant difference.

Bypass volume varies some from model to model. You may get less of the Dreaded Fox Outside Loop Disease from the ones with a bit less. (Look at 'em from the front; some of the bypasses stick out a little more prominently than others). I haven't done a study on this yet, burp wise; this is pure speculation. Adrich measured a bunch of them on Isky years ago, but we didn't test.

Some other thoughts...

Quality control is improved now. You are more likely of getting a good one.

There is a half ounce difference between the earliest Sandcast 4 bolt head, and the latest 50th Anniv. This may have some mild importance to you. I am not including the muffler here.

From about 1970 on, the motors accommodate mufflers. A plus to many of us.

On the Sandcasts, the mounting holes on the lugs are mighty close to the edges. These models are more damage prone from crashes.

As the die cast cases progressed from the early 50s to present, you can see a progression of more gussets, and general strengthening of the case. So they are a bit better when you wreck 'em.

There is some difference in the wrist pin clips. I haven't paid much attention here. Someone help me out.

Do you like the early Austin Craft NVAs? I do.

The early Foxes don't have a flange on the spraybar where you stick the fuel line. This is unhelpful, since the line can easily persuade itself to come off (especially if silicone; this is one instance where the cheap clear neopreme is better. It likes to grab.

I like the Sandcasts because they are Period Correct on OTS and early Classic designs. But that is just me.

50s and 60s era Foxes often came with aluminum filings in the case at no extra charge. But, hey, if the engines have survived this long...

Do you like Matte or Shiny? Plenty of choices. No running difference that I can tell.

If you have a Black and Gold model, spend $150 on a serialled 50th Anniv. B & G Fox. It would look cool. Ted Fancher: didn't you say you might do this, once? Or was it someone else here?

I'll think of some other stuff...

Dennis,

While you have stated the feelings of some of my friends, I do not share your sentiment.

A nice Fox 35--agreed, they're hardly all "nice"--on an Oriental or other model of this era is not only period-correct, it makes a real nice package which is not demanding in any way to handle.

And the results may be mythical within your experience, but not in mine.

Bigiron

In my opinion, it wouldn't take much effort on Foxes part to make a really good engine with improved performance. It would be nice to buy a Fox 35 that you didn't have to send to someone else to make it right!

My vote for the best would be the 50th because it has the strongest case.

I agree here 100%.

The 50th case is by far the best improvment Fox has done.

I couldn't tell you much about a NIB engine, since I have been building all my motors from new parts since 1990. This was due to Fox running the engine before shipping it and 70% of the NIB need a P&L to rework it and make it run at it's Peek.

Larry

I have NIB 40th Anniversity version. How can one tell a first run from a second run?

Thanks.

What happened was that the tool that Fox used to cut the small groove in the piston for the circlip got dull, and when they sharpened it, they got it too wide and cut the entire end of the hole in the piston out and no circlip would stay in. So, to remedy that, they moved the groove farther from the end of the hole . In doing so, the results were that the wristpin was too long and would push the circlip back out as it wouldn't drop into the groove fully. This push out would usually occur the first time you really got the engine up to running temperature. On the second run of the 40th anniversary engines they corrected the problem. You can take a Dremil tool and "CAREFULLY" grind about 0.005 inch from one end of the wristpin and then de-burr it and be ok.

Ron B.
F4Fguy

Run it.If the wrist pin keepers come apart,you've got a first run.

Dan:This is too easy!

THe main complaint I have with the newer Fox 35's is they are very hard to take apart. When they thickened the crankshaft counterweight/web, they did not increase the other clearances, and it is very difficult to take the rod off the crank pin. I think they even use a mallot to hammer the rods on the crank pin in the factory. John Lowry said you have to place the crankpin at the 7:00 position in the case to remove the rod, but on a new engine that doesn't work for me. Anyone have a solution?

Larry

How do you tell if you have first or second batch? Mine is still NIB.

Don't throw those Fox 35's!!
Many of the wiser modelers who don't have the expertise, inventory, or patience to come up with a Fox 35 that runs well find they do very well on the ends of their rods when fishing deeper water. As to the origianal question on which model is best, the shiny versions seem to attract fish and the 40th anniversary provides superior "feel" when used with a quality graphite rod.

Dan:

Just when I think I'm out of it,They try to SUCK me back in again!!

We need some feedback. I have the Aldrich version of this motor, with the piston and sleeve done in Russia. I've only flown it a few times, on an odd model (Sig Fokker) so I don't have a definite impression of it yet. I can say that it runs smoother. Also, the fact that I run a Fox muffler on it further masks its attributes, since my other, older Foxes go mufflerless, or with a tongue.

Currelll

I am sorry, but I simply do not agree with this.

Was this a special deal from Fox, or wasn't there some kind of similar offering from Brodak? I have glimmers of memory saying it was a Brodak package, do not remember it being a factory sale.

For this kind of money, one would have been--still would be--far better off to spend the money with either Larry Foster (RSM) or Lew Woolard. For one thing, in my experience you'd have to toss the Fox-produced hemi head right off, thus bringing the cost up to a level pretty much in line with a tuner-supplied motor. Without all the other benefits, of which "simple" and proper assembly is one of the most salient.

Also do not agree with previous whining about Fox going for a do-over on the 35. Cripes, I'm really happy the things are still readily available and that parts interchangeability is not a problem.

Also, the current crew at Fox might not exactly be up to speed on some of the stuff Larry, Woolard, BigIron and other are doing. Reference: Fox hemi-head kit. I like the *stock* head better.

And don't forget that if effort goes into a spiffed-up Fox 35, we'll be paying more for the next-generation motors. We are immensely better off--assuming one even wants to run a Fox 35, and I most certainly do in two events--having access to a huge data base of how to handle Fox 35s; people like Larry, Lew and Marvin; and your local Fox 35 expert, whomever that might be.

In other words, be real careful what you wish for...

I want to make it clear that I do not own even a single example of said motor, although I have seen at least a couple pulling models around the sky.

They appear to be nice pieces of work, although I was always concerned about what I viewed as the design being the work product of a committee, not a particularly attractive prospect. And while I hope any quality issues have been effectively dealt with, this is one of the challenges inherent in having goods produced in any ex-Soviet bloc country. Without going into details, I know this much, much better than most.

Still, when looking objectively at the market, one can logically assume that any new motor which offers the same kind of power as a Fox 35, ideally more power while keeping characteristics of power delivery unaltered, would be an instant winner even at a $175.00 retail price.

With a retail of a mere $100.00, nearly all of our "substandard" Fox 35s ought be in storage, Larry Foster and other tuners relegated to reworking anything and everything except Fox 35s.

While I don't have good numbers, all indications are that more people are using the Fox 35, not fewer. Larry doesn't seem to have a moment to spare, Randy's investing in a high-zoot crank, hemi heads, stuffer back doors, ABC sets, even a ceramic-coated liner with appropriate piston are all available.

Whatever it is, the "soul" of a Fox 35 versus the appliance-like nature of O.S. engines--just like the debate which continues unabated between Harley riders and those on Jap Bikes--the ol' Fox 35 doesn't seem in any danger from new kids on the block.

Gotta respect that kind of staying power, even if one prefers a different powerplant.

UMM! no no no ... thoses foxes are junk!! throw them away- get rid of them - I'll take em off your hands for $15, no $10 a pop - there worthless, you don't need those break in and burps headaches!!!

But, once more, I see no correlation between the particular models of the Fox, and overall run excellence (or adequacy, if you are not particularly a Fox fan).

I have at least two dozen, and have run/flown most of them. One of my best is a Sandcast 29. Another good one is a 40th anniversary. And so on. One constant is that the better running/starting ones have a lot of hours on them. They wear their blackened heads as a badge of honor.

Basically, what is changing over time is the case, with variations in the bypass area. The early cases are more vulnerable in crashes, but are lighter. The later ones probably throw off heat a bit better.

I think they have sold over a million. It still amazes me how this one particular brand and model can imflame passions they way it does.

Ask for the high zoot crankshaft plus all his usual mods.

Break it in per the instructions.

You will now have the best Fox in the long and venerated history of the motor.

My two sense.

Cy.

Then again, I am just a newer guy, so as long as it starts and drags my ship around, I'm happy

That sounds like a good idea. The muffler you're using (an OS #702, possibly?) would be somewhat lighter and less restrictive than the Fox mufflers of that era. I may have to find one to try that on some of my older Fox .35's. I think that it would be difficult to over tighten that one small screw enough to distort the case badly, as opposed to those aftermarket mufflers with the giant hose clamp straps and attendant large, easily over torqued screws.

Thanks.