optimus 8r sputtering burner?

Hi All,
Yesterday I received the 8r I referred to in this thread:
https://classiccampstoves.com/threads/7090

On unpacking, it the burner looked fine (a bit sooty, but in overall good condition and complete) but the tin is very poor and probably beyond worthwhile repair (more of this later...). The operating spindle and tank cap appeared fine so I filled it and fired her up!

After a bit of a false start it lit fine and burned well, but I noticed that on 'full throttle' there was a slight 'sputter' to the sound that the burner made. This wasn't visible in the flame which appeared strong and blue - it just didn't sound as 'smooth' as my Russian 8r clone (my only source of reference for 8r's).

So, I stripped the burner down using the excellent tutorial on here and after removing the wick and graphite valve stem packing, I cleaned all the metal parts in my ultrasonic bath using warm water with a dash of vinegar and detergent.

This brought the burner up like new and I reassembled it only to find that it still makes the slight sputtering noise.

So my question is - is this normal for an 8r and should I bother about it?

Regarding the tin, I've just bought some sheet aluminium and am going to have a go at making a mini 8r version of this!:


best

Matt

 

If it sounds like a distant helicopter then it's most likely correct.
Don't have an 8r meself, but its 1st cousin, the #99, and it has that lovely, fast "frtr frtr frtr frtr frtr frtr" throb to it.

 

That's just the sound!
I'll consider it a 'good runner' then

Many thanks
Matt

 

Hi Matt

If you are still going to make a case out of aluminium I will take some close-ups which show how the metal was cut so that it would bend easily. I could also take additional photos which show the case in more detail. Let me know.

 

Hi Trevor,

That's very kind of you and would be very helpful!
I've been trying to work out the precise construction from the pictures you posted in your thread - if you have time to take any others, I'd really appreciate it.

I guess that I'll have to adjust the design to take account of the fact that I don't have any sheet metal working machinery in the garage (who does!), but the construction seems to be mostly riveted with few complex folds.

Thanks again for the kind offer

best
Matt

 

Personally I would have said it was somewhere between 'floodafloodaflooda' and brrbrrbrrbrrbrrbrr.....relaxing as rain on a tin roof anyway you spell it...

 

Naaaaa... I reckon its more of a ptptptptptptptptptptpt...

 

Well, the debate on the exact nature of the sound gives me great confidence that my burner is good!

For what it's worth, to me Ian's ptptptptptptptptptptpt is about right, but there's also a bit of approaching distant helicopter in there ('approaching' to up the frequency a bit!)

cheers

Matt