I have seen a few 25fp's at swap meets but I've yet to have seen a 20fp.

Getting all inspired buy this thread , and seeing the previous post

will relate the FP Crank Saga . Theyre All Rusty , in the case of most second had motors from the U.S. !

Las t Night checked & stripped two ' as new ' LA 25s  . Boiled in baking soda solution , then used the green 3M post scourer ,
a screwdriver to turn it inside the port , 320 wet & dry to ' brush up ' the flanks ,
and  600 to polish the crank pin & shaft .

They were only lightly grotty , but enough to reduce life expectancy . Theyre the two bush El Cheapo crank .
( Look Exchangeable with FP Cranks , ive got two But Somebodys ' reworked them ' for Classic B team race , here .
Anyone want two Hi Po Cranks & butchered , Er Ported & shaved - FP25 cases & cranks , lemme know )

Two FP 40s & the Two LAs all had the oxidation , one FP used the OXIDE to re lap the liner , Tragic .
So pull the back plate & inspect the flywheel , on your swap meet finds .

If they arnt all shiney , theve Probly Got STUCK WRIST PINS , like my LA 25s ! Polished up o.k.
acetone soak & clean lands in piston & rod , & Case Bearing & clear the front oilway cutting .

Made a pair of toungue mufflers for them / the 262 . Will pull 7 check the GP Magnum FP clones , justin case .Maybe bolt the LAs in .

One New FP 25 on the shelf .

   Just for reference, if anyone deciphers this, DON'T DO ANY OF IT. If something is gummed up, disassemble and crock-pot it, DO NOT grind/lap/sand anything, just clean it and put it back together as intended. And for goodness sake, don't toss out the factory muffler, since that is both very effective, and makes the engine run better than the alternatives.

     If you lap or sand or grind the ABC cyl/piston assembly, you should go find a replacement, because it will be immediately ruined.

    Brett

You can see there the contaminated surface dosnt present an ideal bearing surface , the wrist pin equally.
Both liable to promote severe bearing wear in short order .

The Magnum 25 FP Clones , one had light crank gooking up , both had wrist pin ditto , more run one worse . Other no head/ piston deposits ,
but still the nitro had got at the wrist pin .

Hence the neccesity to flush & oil before long term storage .Ball Race motors it gets to the bearings , the nitro lets the oxidation ( rust ) start .

Poor picture of the FP 25 clone , for the record . Both Stripped . cleaned , polished shafts , contamination cleared , and ready to go .
Will report on behavoir , had in mind the classic stunt comp, Sunday . But the Ute & other priorities will take precedance .

The mufflers from Dubro Extn , 1 1/2 long , so about four times the volume of the little brodack ' chip ' mufflers .
Had Fox 25 BB mufflers on it before, modified to fit . Ones missplaced, hence replacements .

New Control Line Stunt engine . !



Cleanliness is Next to Godliness . 

Wash in Solvent or Alcohol , Ensure NO GRIT remains. A clean paper towel should show NO Contamination , after duress on component/s

Triumph ( Even Though its NOT a Pre Unit , which were more carefully built than most unit construction triumph / BSA's
( Nortons were later built in the olde J.A.P. Factory .Often by careless youths . . . .



Drilled / Lightened , narrowed , polished Timing Gear set . The Case itself would perhaps be polished INTERNALLY for better oil flow down / less drag .

And yr garden variety  or maybe not so garden variety , Cad. & other High Po were more ' Quality Control ' Oriented ,
 350 Chev.  .



Again objective is better drain down ( if de burred case ) Less Drag . Lower Stress raisers/ raising . MORE Horsepower .
Better Reliability .
Rather than modifying , ' improvements ' and greater attention to deatail . At that era of engineering .
Not Everyone had the pockets for a 1.000 Hr hand built ' production ' engine .

While deburring / cleaning & polishing likely wont harm a Aerobatic Engine , its more the provinance of Race / Hi-Po options.

THOUGH here the pre requiste was the elimination of debri & contamination of second hand used C-L powerplants .

At Your Own Risk . Common Sense & some degree of engineering Knowledge and Princaples is assumed / required .
So Study or Practise on junk. Some have a natural affinity / touch . Less is usually More , in ' altering ' anything .
unless a master of the art .

So we Dont Dissagee with the ' Brett Buck Tune ' ; but started from Ex R.C. junkers - so used what we can get , here with the FP/LAs ,
The Boxed FP Remaing is the RC with the ' Correct ' muffler , and the LAs are the ' Correct '  Venturies  Now ..

Ive put this stuff on , as second hand FPs / LAs unless correctly cared for are liable to corrosive deterioration ,
Which unless corrected is leading to their premature demise .

Ok Dane you can put my Silver LA back together now 🤣.

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