ORIGINAL: airraptor
ORIGINAL: EscapeFlyer
Using an OS plug will void the warranty with your Nova Rossi. OS plugs are not sized well. I wouldn't recommend them anyhow.
The NovaRossi plug Dox recommended is a cold plug. 15% works great! As far as pipe length.. There is a difference in RPM between the NR 50400 and the Mac's muffled pipe (Mac's giving you just a little more). But Jim Oliver has documented this advantage only between 150-200rpm. That is with an 11X7APC. I should say that this is on an older, but new, C61F RE NR.
What pipe and header are you using? There may be an adjustment in the header between the two.
Brian
How will this void the warranty?
Some of the NR engines require a short reach plug.
I have not tried a standard long reach plug in a NR engine but due to the increased depth of the LR plug....I suppose that it is possible for the piston to hit the plug at TDC.
I did compare the NR short reach with a standard K&B 1L and some NIP Rossi 4 plugs and there is a considerable difference in length.
Also....the NR plugs could be more robust in that at high rpm and high compression the elements have been known to vibrate loose and fall into the cylinder.
Then, the element gets trapped in the exhaust and destroys the piston and sleeve.
This is a well known but probably forgotton problem that will make itself known again now that we are starting to use this type of engine again.
Don't run these engnes too lean or the pipe too short....the plugs will get pounded for sure.
Keep the pipe a little long and set the engine mixture with the in-flight needle with the transmitter just before takeoff on every flight.
The in-flight rpm will increase and the engine will get further along on the long end of the pipe and start to really howl.....without blowing the plug.
Back in the mid to late 80's I was mixing my own fuel...nothing secret or impossible to find with this type of engine....
I used with great results 5% nitro, 18% K&B X2c oil.
That oil was I believe....20% castor.
An equal oil today would be Klotz.
My engines always ran as good and most of the time better than anyone's and I never had a failure in 5 hard years of flying both days every weekend and all the contests within driving distance.
The wrist pin wire clip is another well known part that fails regularly.....it's best to replace these clips at every bearing change.
Rust and corrosion is your and the engines enemy.....the clips rust quickly.
I used to use castor oil for after run oil oil but I have found that any brand synthetic motor oil from Walmart works better and never gets sticky and gummy.
And.....the engine fires right up again later.
I like the most thin viscosity oil I can get....I've forgotten the weight but I think it is 0-10 or similar.
The Dave Shadel Performance Specialties oil works wonders as well.
I've never tried air compressor refrigerant oil but I think it is similar and should work well.
Dave