MVVS 3241 muffler again
 

Ok finally if you go back to post dated 12/30/11 finally got the pix of the muffler mounted on the engine MVVS 15D muffler tuned 3241 martin
this was a chore to get upload martin no o rings with them but harbor freight to the rescue

AH here it is no need to back track did it in seconds go fiqure

no need to back track

RE: MVVS 3241 muffler again
 

Cut O-rings from the silicone tubing that's in the box. They work better than the original rings.

RE: MVVS 3241 muffler again
 

Pe thx simple and easy too, so simple never thought of it , got one of the engines from you several years ago its a 10+ martin

Lets hope it stays in production, a comeback on the 09 would be great

RE: MVVS 3241 muffler again
 

The Nitrile o-rings will not like diesel fuel...

The 3241 muffler is the recommended muffler for the Diesel engine. What did you use before? The 3235?

RE: MVVS 3241 muffler again
 

Mr cox yes on the 3245 muffler thx for tip in the nitrile o rings will see if find some vitron for the parts spares
silicon a no no with diesel ( at least fuel line) martin

RE: MVVS 3241 muffler again
 

The large diameter silicone thin wall tubing is what you cut a 1/8" ring from and use that. It holds up just fine.

Greg

RE: MVVS 3241 muffler again
 

What do the MVVS aficionados use to seal up the standard side muffler for 2.5 cc?

Mine leaks like a *&$% and it won't fit on the stub with the silicon tubing "O" ring.

I am thinking I may need to line the muffler stub recess with permatex RV sealant or similar to stop the leaks.

RE: MVVS 3241 muffler again
 

Fiery I used Koppercoat think made by permatex (autoparts store) works great also used very thin coats to seal rc carbys on the o ringalso on muffler seams on 2 and 3 pc mufflers a couple of my irvines had minor seeps no more martin

do not use the reg black stuff

RE: MVVS 3241 muffler again
 

The engine comes with silicone rings and have sealed fine on mine for bench running, haven't used it more than that yet.
Silicone only swells a little from pure diesel fuel and the exhaust oils have been fine for the limited running that I have done. The regular silicone exhaust deflectors are also fine, even after more than one season of flying. Nitrile on the other hand quickly dissolves in pure fuel, and can't take the exhaust residues, even from glow engines.

RE: MVVS 3241 muffler again
 

Took a few pictures to show what we are talking about. The stock seal, from a thin walled silicone tube, and the different mufflers. There is also a straight pipe for rear exhaust set-up (not shown).

RE: MVVS 3241 muffler again
 

The standard muffler I have is shown at the top. I also have the black mini-pipe.

The mini pipe fits fine, but with the stock silicone "O" ring installed on the manifold I cannot fit the standard muffler.

I guess I will have to seek out suitable thinner walled silicone tubing.

RE: MVVS 3241 muffler again
 

I have dieseltested the rings cut from the exhaust extension tubing. They hold out well enough, and seal tightly.
The 3235 mufflers (3.5cc engines) are no longer available (only 3 left in my stock), so hold on to them if you got some.
2.5cc engines need the 3225 muffler.

RE: MVVS 3241 muffler again
 

It should be noted that there are two types of connections for the exhaust. The old type uses the seal on the muffler and it slips inside the exhaust stub on the engine. The newer type has the seal on the stub and the exhaust slips over the stub on the engine. My first MVVS 2.5D uses the old type.

Martin, take a close look inside that packaging. There should be two clear silicone exhaust seals in the muffler box. Both of mine have them and it's easy to miss them.

Greg

RE: MVVS 3241 muffler again
 

The 3241 muffler has the rectangular section sealing ring outside of the engine exhaust stub as on all new 2.5cc engines. That is the seal I was talking about, that is better replaced by a ring cut off the exhaust extension hose.

RE: MVVS 3241 muffler again
 

Greg and Pe yes I have the silicon tubing pieces will make the seals as Pe suggested THX martin
and do have a new 3245 clamp on muffler but will use the 3241s
Mr Cox have the middle one in the pix and not a good seal as stock had to use Koppercoat to stop it ( the leaks)

The 3241 comes with a nice clamp that fits over the end and allows clamping to the Fus.

RE: MVVS 3241 muffler again
 

To use the pictured middle one muffler is is advantageous to solder two brass pieces together and turn a ring out of that so it will have the inner diameter of the engine stub seal section, and outer diameter of the inner muffler neck.
After turning, loosen the solder, so you get a split collar. This gives the muffler clamp section a bit more material to hold on to.

RE: MVVS 3241 muffler again
 

PS
When using the 3225 or 3225A muffler, be sure to clean off all paint from the mounting bore inside. That will make it fit well. Also remove the paint from under the tightening bolt head. When the muffler gets hot, the paint softens causing the muffler to get loose.

PS PS
The 3225A is still available in my stock.

RE: MVVS 3241 muffler again
 

Pe,

If I may risk a question or two, I have two rear exhaust MVVS engines I bought back in the early 90's and intend to put to work in the near future.
At the same time, I had bought minipe silencers for both of them.
First engine is an MVVS 2.5DFRC, the exhaust is number 3242 - top one on picture.
Second engine is an MVVS 3.5GFRRC, the exhaust being number 3244R - bottom one on picture
First question, is #3242 the correct type for the 2.5 Diesel ? (it does fit mechanically)
The box label reads: "pro motor 2,5 GF+GRR"
Second question, what sort of rpm are these silencers tuned for ?

Thanks for any information.
Jean-Marie

RE: MVVS 3241 muffler again
 

the 3242 comes on song at 17,000 in a glow engine. With diesel probably slightly lower due to different port timing. try it out.
the 3.5cc 3244 is on song above 14,000 rpm. Using the 3242 on 3.5cc lets the engine operate at 18,000 rpm or more.

RE: MVVS 3241 muffler again
 

Pe,

Thank you, I've taken good note of these figures