tt 25 rust
 

i have got this TT25 which i have converted to diesel and has never seen methanol, it has been at me for 8 months all of a sudden it started makeing a funny noise like a bearing has gone and i decide to open the back plate and got a shock the crank was a block of rust and the main bearing was full of rust. then i opend up all my diesels and none had this trouble what can it be this is the engine i use most almost every week end??????????? [:@]

RE: tt 25 rust
 

Ldalmas: Are you using MEK in your fuel? If so how much?

Regards - Steve B.

RE: tt 25 rust
 

Ldalmas, What fuel mix are you useing ? , how fresh/old is it ? Martin had rust forming in his MVVS 2.5cc diesel too. I am wondering if its bad ether, ie poorly washed and still containing acid , it could also be ether breakdown forming corrosive peroxides.
I read somewere that ether should be stored with a peice of copper wire in the container to prevent peroxide formation. Anyone else heard of this ?
Stewart

RE: tt 25 rust
 

my guess its MEK martin

RE: tt 25 rust
 

Is your TT fitted with a muffler?
David Owen

RE: tt 25 rust
 

i use mekp but i have other engines useing the same mix and never had these sort of problems and last night i opened them to confirm , one stange thing is that only the crank rusted there are no signd of corrotion on the other parts the aluminum case an con rod are nice and shiney i am useing it with a standard mufler and only useing 2% mek


laurence

RE: tt 25 rust
 

The rust problem is consistent with the use of a muffler. It can happen virtually overnight.
Corrosive by-products of combustion in the exhaust residue condense inside the engine and attack steel parts. I have seen this happen to several engines fitted with large, expansion mufflers. It does not seem to affect PAWs with their smaller muffler volume.
It is more likely connected to the ether content, rather than the inclusion of additives such as MEK.
The solution is to flood the engine with a dwf such as WD40 after a day's flying, to close the exhaust port and to ensure that the model is not hung nose down.

David Owen

RE: tt 25 rust
 

David i think you are right because with closer inspection the pressure nipple on the muffler has its chrome corroded of at the endut what i cant understand is why this engine and not the others?
laurence

RE: tt 25 rust
 

I don't think your TT has been singled out for the corrosive treatment. Just a combination of the factors I previously mentioned.
Dave