Petter M rebuild

The atomiser gap at 1/16th, I've had a look at this and we're a way off there, atleast an 1/8th. If it adjust the nozzle to get this closer it isn't locked in anyway, likely to rattle loose and get sucked in. I must be missing something.

Foden wrote:

Jonacol wrote:You are very kind Pete. My son, also a Jack, is very keen on old stuff. We rebuilt a classic mini.over four years and he's leading on the petter. They are a great way to learn about engineering, we're currently arguing about whether to repaint it!

Looking at that pic of the engine I would leave the paint and when the engine is finished give it a coating of boiled linseed oil which will enhance that original paintwork.

Pete.

I would go for the linseed oil also but mixed 50/50 with white spirit otherwise it will take years to dry.

Jonacol wrote:The atomiser gap at 1/16th, I've had a look at this and we're a way off there, atleast an 1/8th. If it adjust the nozzle to get this closer it isn't locked in anyway, likely to rattle loose and get sucked in. I must be missing something.

Hi Jon,
There is a possibility your atomiser is broken, can you post some more pics ? Could you measure the overall length from end of the tube that screws into the bronze ball valve housing to the tip of the nozzle ?
Thanks

I had a word with a clubmate today and I might be getting confused! Apparently Graham had two Petter M's at the same time, (a glutton for punishment that lad!) this one and a black one which he ran and then later sold. My mate thinks that it was the black one that came from the harbour or a boat and not this one as he made a brass plate with the information engraved on it which was fastened to it. Also the other lad who had the engine last has apparently found some .more parts for it so I will ask when I see him tomorrow just what it is he has found!

Pete.

Chatted with Alan today at a local event, as far as he knows he has no other parts to the engine but will have a good look under his bench 'just in case' anything is there. The engine arrived with him in a variety of boxes via other club members so anything could have happened! Regarding the brass spec plate; the chap I gave it to to pass on to Alan has no recollection of that event but will search his van when he gets time, don't hold your breath though.

Pete.

Re atomiser. I bought Jack the Petter workshop poster for Christmas and it shows the atomiser head with a lock nut which on ours is missing, problem solved I think. Just got to make a nut!

Jonacol wrote:Re atomiser. I bought Jack the Petter workshop poster for Christmas and it shows the atomiser head with a lock nut which on ours is missing, problem solved I think. Just got to make a nut!

Yes that would certainly help and explain why it wobbles when unscrewed.
If the brass plate doesn't turn up, there is a chap (Kevin Buttle) who should be able to make you a repro blank plate which can be stamped with the correct number. Not sure if he is on here but you can get him on Facebook.

The wall chart is a good Christmas present...
Seasons greetings!
Dave

Our jet appears to be somewhat shorter than intended, looks like the thread is too short, possibly snapped off at some point. We cant adjust to the 1/16th piston clearance figure. Looks like some creative engineering needed to make a threaded spacer or new jet part required. I wonder how they drilled the small jet holes in the 1920s, fair play to them.

They drilled the holes the same way as we do today, carefully, what you need to find or borrow is wire gauges to determine the jet size, this will then tell you the drill size required.
to drill the holes you will need to spin the drill at very high speed, for instance a 1 mm drill will need to spin at 3000 rpm drilling brass.

maryalice

I think it's pretty amazing that in the 1920s they could drill a sub 1mm hole at all. It's not like they could by that size drill bit off the shelf for a few pence like today. I'm an ex tool maker and even with today's kit it would make me sweet a bit!

Yes, definitely been broken off or cut short for some reason which is unfortunate. I am sure an extension could made to allow you to keep the original atomiser. There used to be a regular supplier on Ebay but I believe is now retired and no more batches being made, I think there may be someone else making a few now and again, Facebook may be a better option to hunt one down, meantime I would be looking at options to manufacture an extension piece. Possibly sleeve over what you have with a machined tube and silver solder this in place and thread the new end to suit ?

FowlerFan,
I think your thinking of Jock Mcgowern, he retired a year ago, didnt see you and your Dad at Dorset last year.

Maryalice

Hi Martin, Hope you are well. We weren't at Dorset last year, we were down for the 50th event the year before which was excellent. Might be another year or two before we are back. Yeah, it was 'rattleknackers' on Ebay who was McGowan Engineering.... he served the hobby well for many years, I recall in the pre-internet days requesting his price lists via snail mail !! How the hobby has changed since those days......!! Cheers Dave

We're back on the engine after sourcing some flywheel weights and a new jet. Fitting the governor gear witha key, I'm a bit stumped. Is the gear key very short without a head i.e. only as long as the gear is thick?