Hi All.

     I have a McCoy .35 Lightning Bolt engine that has a poor p&c fit.  I also have a new McCoy Series 21 .35 engine  I have been told that by swapping the p&c , I will obtain a great running McCoy RH that will last forever. Anybody make this swap and if so, what are your opinions?

     I have been told that  the Series 21 p,c,and con rod will drop right into the RH case with no modifications.  I was also told that the RH case has  to be bored .005" to accept the Series 21 cylinder.  The  RH Lightning Bolt Case is a must as it has the bridges in the cylinder for the Series 21 Dykes ring.  What does this mean if I am swapping the Series 21 cylinder?   Do I transfer the Series 21 cylinder to the RH case or do I use the RH cylinder in the RH case with the Series 21 piston and rod?

      What are the facts of making this hybrid?

                                                                                                                                                 Tia,

                                                                                                                                                 Frank McCune

Frank, no need to use the Series 21 cylinder jug if the RH jug has the bridges.  All you will need to do is swap the piston and ring.

I have several that I have swapped the whole set and some that I just swapped the piston.  All keep the great 4-2 run of the Red Head!  I recommend it highly!  I would also get a new ring form Frank Bowman, they seem to last longer than the original ring.  The .29 is the only other swap where the cylinder will drop in.  You have to bore the RH .40 case or simply use the piston only. Nothing on the .19 works.  If the RH rod has any wear, I use the Series 21 rod.  I fly OTS with a Super Clown and a Hybrid .29!  Great engine runs!  I am putting a Hybrid .35  in a memorial Goldberg Cosmic Wind that my best friend's Dad used in 1963 to teach me how to do "tricks".  I ended up with that RH.35 and there was not enough compression left to start it.  It will be a surprise for my friend.

Send me a PM if you need any more info.  It really does create an almost PERFECT Red Head .35!

Bill

Hello Frank,
I second what Bill says, the total swop is the best way to go, but if you can't bore the RH case to take the cylinder then just use the piston and rod.
I am a bit wary of suggesting the usual way to get a better P/L fit and I will probably get some flak. However quite a few people use a small hammer and or a drift, to tap the top of the piston. This will give a much better fit IF you know what you are doing! Sometimes I have overdone it and have had to lap the piston in again! I take NO responsibility if you break your piston! Seriously, this does work if you are gentle with the hammer. Other  people may chime in about this method of fixing Red Heads!
The RH pistons are of sintered manufacture and this is probably why it works so well and why the piston wears out faster than most. The same firm that made the RH pistons also used the same process to manufacture pistons for the Johnson range of engines, so I am told. Looks as if the sintering schedule was different, because the Johnson pistons were very long lived.

Regards,

Andrew.

Hello Jim
I think I am right in saying that we  even fly stunt with spark ignition engines! So compared to that, the Red Heads are pretty modern technology!
It is a pity that the RH 35 were produced down to a low (very low!) price. The design if properly executed would have made a pretty good performer. I have rebuilt several of them with better materials and I would brag (just a little) with more accurate machining of the parts. The resulting engines have performed flawlessly to this day and give excellent old fashioned "break" type runs.

Regards,

Andrew.

I've been wanting to give this a try for a wile now! I only have one lightning bolt McCoy 35 though. I have a bunch of series 21 engines though. Can you put a 29 series 21 piston an cylinder into a 35 red head case?