Identifying engine mods & who is Byron Barker?

I have some OS MAX FP engines that I know have some mods but I don't want to tear them down to figure out exactly what the mods are.

The box that they came in has a receipt from Art Adamisin stating "rework for stunt" for 2 40's for $90 each and 2 35-S including new piston & liners for $85 each.

Also in the box is an FP 35 inscribed with "BYRON BARKER" (the Barker is almost unreadable, so it might be something close) the date 4/11/01, has "hemi" inscribed on the head, a black nylon (delrin?) venturi, a S. Tigre NVA and what I beleive to be one of Big Arts mufflers.

One of the 40's I can see that the ports on the side closest to the venturi is drilled and opened up and appears to have a stock venturi and NVA... the other looks stock but has a small venturi (maybe a 25 size?) with a S.Tigre NVA

Removing the backplates on all did not reveal any obvious mods...

If I can figure out how to post pics (again!) I will but I am working all weekend and may not get the chance...

One last question: is the Hemi head for a FP 35 or 40 still available?

Thanks!

Different folks hemi the head. Usually this means they've lowered the compression by reducing the squish band. I believe Byron Barker does this. Someone on this forum will have his email I'm sure. I have two FP type engines that were modified this winter. The heads were hemi-ed and the main ports raised a bit. I've only been able to fly these engines a few times. Looks promising.

FPs can work famously as stunt motors, out of the box, with the right fuel, prop, muffler, venturi and an extra head gasket or two. Excellent power. Very useful 2.2 break. They're often finicky tho, and difficult to tune into the sweet zone. A click off the correct needlevalve setting and you've got a runaway. Especially true on profile planes, which are subject to weird vibration harmonics. I'm looking forward to working with the modified engines. To see if they retain (enough) FP power while proving more flexible with a wider zone of useful adjustment.

>I have some OS MAX FP engines that I know have some mods but
>I don't want to tear them down to figure out exactly what the
>mods are.
>
>The box that they came in has a receipt from Art Adamisin
>stating "rework for stunt" for 2 40's for $90 each
>and 2 35-S including new piston & liners for $85 each.
>
>Also in the box is an FP 35 inscribed with "BYRON
>BARKER" (the Barker is almost unreadable, so it might be
>something close) the date 4/11/01, has "hemi"
>inscribed on the head, a black nylon (delrin?) venturi, a S.
>Tigre NVA and what I beleive to be one of Big Arts mufflers.
>
>One of the 40's I can see that the ports on the side closest
>to the venturi is drilled and opened up and appears to have a
>stock venturi and NVA... the other looks stock but has a small
>venturi (maybe a 25 size?) with a S.Tigre NVA
>
>Removing the backplates on all did not reveal any obvious
>mods...
>
>If I can figure out how to post pics (again!) I will but I am
>working all weekend and may not get the chance...
>
>One last question: is the Hemi head for a FP 35 or 40 still
>available?
>
>Thanks!


The porting is rework to alter the timing, and sometimes the cylinder liner is lowered. Each engine reworker has his own "recipe." As you aquire engines from most of the guys who do rework, you'll learn to recognize their handiwork.
Art Adamisin (AKA Big Art!" has been around since the Dead Sea was sick, and is well known for his work with any kind of OS engine. He makes mufflers also. Byron Barker does excellent work also, and he does the work to the head to make it a "Hemi". I don't think he has them seperate, but I could be wrong. Most guys that do this type of work mark the engines in some way so they can keep track of what was done to they.
These should all be great engines for you. BAsiic set up should be hot glow plug, muffler of your choice, 10/5,11/4,11/5 should work for prop range, and a good 10% nitro fuel with 20 to 22% oil. Depending on the model and weight, 10,000 to 10,500 RPM would be a good starting point at take off.
Good luck and have fun,
Dan McEntee

As mentioned elsewhere, most everyone who does rework has his own "recipe" for what he is trying to achieve. The hemi mod lowers compression, but... Art's mod uses a wedge head which has been modified with a head button.

A number of years ago Lew Woolard made a head for me that would use the Fox "buttons" making it easier to test different configurations. We made a number of different chambers for the head, and even tried Art's head, but never could find a head shape that worked better than the stock one. Interestingly there is a group that modifies Fox engines (40s) that makes a head for them that is nearly identical to the shape used in the stock OS FP.
Remember, I said "work better". Some of these work and work well--Art's for instance. He was trying to achieve something else I would think, but for me it just didn't improve performance over setting the stock head at the correct height.

Art's engine is quite powerful--you can turn a 12-6 with it. But be aware that if you run it upright or inverted you will need to run all synthetic oil or it will develop a "burp" in the intersections as I found also with our 40 mods. I never had the courage to use all synthetic, but he recommends it with his engines. Just don't let them go overlean.

And Byron Barker is still around down New Albany (IN) way. He is a CD for a contest they hold there every year. You should be able to find his address in the PAMPA directory. And he does good work.

Just to clarify, reducing the squish band doesn't lower the compression ratio, enlarging the chamber does. The reduced squish band is a result of enlarging the chamber although the chamber can be enlarged without altering the squish area.

Randy Ryan <><
AMA 8500
SAM 36
BO all my own M's

All right! So the name is in fact Byron Barker...

Now as for the two 40's one is most likely a Big Art mod and the other is not nessesarily so. The one with the raised port is probably Art's handiwork, (does he use stock OS click type NVA's?) and the other with the 25 size venturi may just be someone's using what ya got or other experimental mod...perhaps. Of course I am speculating at this point.


Leonard, How does one determine the correct head highth? The FP engines I have altered myself I did nothing more than to change the intake port (only) and add two head shims. On the port I angle the top part of the port about 30 degrees and radius the lower part, then radius and contour the inside (towards the prop drive side) of the conrod side of the crank and polish it, (I learned this from Antone Kephart) and what I end up with is an engine that runs much more efficient (noticable fuel economy) and holds the needle much more consistently. Though I don't fly enough to have perfected the needle settings (Has anyone? ) I have done these mods to four engines and three responded as I described and one still ran-away with less than half a tank of fuel. Typically I run a sloppy wet 2 cycle needle because the 2-4 has been elusive for me...

Back to the original thread... Can someone describe Big Arts mods that I could spot just by looking? Thanks again guys!

>(snip)
>Leonard, How does one determine the correct head highth? (snip)

Experiment. Of course, you also have to set the deck height (top of piston to top of cylinder when at top dead center). If this changes (and it most always does on production engines) then it must be corrected or head height changed along with it (although it also affects timing)





>(snip) I have done these mods to four engines and three
>responded as I described and one still ran-away with less than
>half a tank of fuel. Typically I run a sloppy wet 2 cycle
>needle because the 2-4 has been elusive for me...

If three responded and one did not, then that one is different (0bviously). Deck height could be different (I have seen 15 thousandths difference between production engines) or, since you are really guessing at the angle and amount of port change, the port height could be different. On the mods I do, 10 thousandths difference between "spot on" and too high resulted in an engine capable of turning only an 11 inch rather than a 12 inch blade prop.

>
>Back to the original thread... Can someone describe Big Arts
>mods that I could spot just by looking? Thanks again guys!

On his 40, Art changed to a button head and a wedge type button. Removing the head will tell you if this is so. But, more obvious, Art also angled the exhaust, and used a muffler with an angled back stack. This is quite obvious on both the engine case and muffler. Art also made an adapter (not part of the engine mod) that would square this up again if desired. I tried this with and without the angled back muffler and couldn't tell any difference in performance. Skipped the step and saved time and money.

Thank you Leonard!

The gent I got these from had one of the FP's just like you described, so this means that the ones I got are not Big Art's work.

You are absolutely right... I guess at the angles and radius'. The one that did not respond had a terrible run away problem before I messed with it. Part of the problem could also be vibration foamed the fuel some. It was over a year ago that I flew it (120% M&P Cherokee) and there is still a couple feet of snow on the ground here so it may be a while before I get to try it again...

I also don't deviate much from my props and fuel tanks. I start with 10/6 Top Flight super M when I can get them (I have two left) or APC. I am completely sold on Eric Rule's GRW Chicken Hopper tanks with or without muffler pressure. I have taken Zinger 12/5, 12/6 and cut them down to 10" but have not tried them yet.

My LHS sells APC and Master Airscrew, so I am not sure just yet on what or where my next supplier of props will come from (probably RSM)

Two things you'll notice on all of my fathers fp's is the filled boost port volume in the crankcase and the button head with wedge shaped chamber. The venturi is usually an extended version of the stock vent with a 0.281 hole. It would also have an ST needle. The head button has to be aligned correctly to function properly. The fp porting is "twisted" to the rear to allow them to get away with not needing wristpin clips in the piston. The flat that runs across the head button needs to be aligned with the porting. If you look at the edge of the button flange there will be a small file mark that should be aligned with the liner locator pin. We also found that the combustion performance of the engine was compromised by castor lube, so we only used pure Ucon in ours. It was and is what we recommend for fp's (and everything else). In our fp's we never used more than 18% and for a while as low as 12% to 15%. Your mileage will most probably vary. The exhaust port flange mod that Leonard mentions was added to the original run of steel piston engines we completed after bench running showed a distinct tendency for a large "bind" to develop while the engine was running (evidenced at shutdown). It allowed the gasses to leave without having to turn on the rear of the flange and leave a lot of heat there on the way out. The engine also showed a wear pattern on the piston that seemed to indicate that the back of the case was getting hotter that the front. The bind went away when we cut the case. It necessitated a labor intensive muffler adaptor but we figured a high end (at the time) stunt engine was worth the trouble.

>Two things you'll notice on all of my fathers fp's is the
>filled boost port volume in the crankcase and the button head
>with wedge shaped chamber. The venturi is usually an extended
>version of the stock vent with a 0.281 hole. It would also
>have an ST needle. (snip)

Dave, Art would put the ST needle in his 35S engines, but I am not aware of his doing so with the modified FP. I have three of his engines and they all have the stock OS needle.

>>Two things you'll notice on all of my fathers fp's is
>the
>>filled boost port volume in the crankcase and the button
>head
>>with wedge shaped chamber. The venturi is usually an
>extended
>>version of the stock vent with a 0.281 hole. It would
>also
>>have an ST needle. (snip)
>
>Dave, Art would put the ST needle in his 35S engines, but I am
>not aware of his doing so with the modified FP. I have three
>of his engines and they all have the stock OS needle.

Hi Leonard. I will correct my statement to "most" of the BA fp's had Tigre valves.. I got carried away. I think that there were a very few that only had the boost blocked. It depended on how much people wanted to spend and what the final installation was. I would say that if people were trying to id a BA fp that the needle would be circumstantial..

One other quick note. BA never modified the liner porting. If you have one that is modified than it's not a BA or it happened after it left the shop.. DaveA

I've had the opportunity to visit Byron @ his shop two years ago. I had a ST G21-35 that he tinkered with while I was there. You can tell his engines by noting the head fins have been milled flat. He told me he does this for two reasons. One, is so he can flip it over and chuck it up flat on his lathe fixture to do the Hemi work (to lower compression) and the other is so the head will run a tad hotter than stock. He also did some port work in the inlets. In the end, that combat motor run suprisingly well. I ended up getting a used LA-46 (blue) that is probalaby one of the best stunt (tractor) running engines I've had. Very honorable man that is always willing to share his knolage with anyone willing to listen. Get a Byron tuned enginge, run it to his recommendations and you won't be disappointed.
DA BUBBA...

If it was easy, anybody could do it!!!

I am convinced I don't have a BA engine... No button heads on either of the 40's

I don't yet own these and am not sure I will be able to buy them at this point (minor, but expensive medical procedure looms) so they may come up for sale in the next week or so...

It would be great if some one could post some pics of a BA engine...

Test run the engines on a bench then run them in a plane. Powermaster fuel 5% to 10%, 22% oil (50/50). An apc 101/2x41/2, good prop to start with. Put a good plug in such as an Enya #3. Enough speculation. See if you like the way the engines perform.

That prop(APC 10 1/2 X 4 1/2) is MAGIC

>I am convinced I don't have a BA engine... No button heads on
>either of the 40's
>
>I don't yet own these and am not sure I will be able to buy
>them at this point (minor, but expensive medical procedure
>looms) so they may come up for sale in the next week or so...
>
>It would be great if some one could post some pics of a BA
>engine...

Hi Phill. Here are a couple shots (Poor fuzzy shots) of one of the original batch of steel piston engines. We consider these the most desireable because the steel piston engines were the most powerfull.

Attachment #1, (jpg file)

My newest aquisition from Byron is a Magnum 36. It includes his typical mods: Hemi'ed head, nylon venturi, ST NV, ect. Have had only a handfull of flights (replacing the 25LA in my P-Force)before I left and didnt get a chance to get it totally dialed in. However it shows LOTS of promise.

I had an FP that he reworked back when I was flying Senior at the Nat's. That motor ran VERY well, and received ample comments on it. I was running 11x5 (pre-Brodak) BY&Os on it and it really liked those props. With the new generation of 11" props from RSM I am very interested in how it would like those.

Ugh...so many airplanes...this war need to hurry up!!