Bast pipe and con rod issues.

Hi all,

I have a STW 4" Burrell which I bought a while ago. It's an early engine, copper tubes in boiler etc. so I'm not sure if the spec has changed over the years but basically I have a couple of questions about it.

The engine has a knock when running, I think this may be coming from the little end bush so I took it apart and indeed there was play fore and aft on the wrist pin when fitted in the bronze bush of the little end which I suspect could be the cause of the knock I'm getting. Does anyone know if STW supply replacement bushes? I checked the build paperwork I got when I bought the engine and it seems when the conrod is supplied it comes with this bush already fitted by STW. I have a part number for the bush, but just wondering if any other 4" Burrell owners have had this issue and have they managed to get a replacement bush?

Also I had the Chimney off to give the blast pipe a clean and noticed the end of the nozzle is quite a large diameter. I also noticed it's threaded inside the pipe so raising the question of should there be a blast nozzle fitted to the pipe which is missing on my engine or is this as standard? Could someone have a quick look at their engine please and see what is fitted? I can not find anything in the build instructions in regard to this anywhere.

Hi Bartman.
first off the blast pipe issue the end of the pipe has a reducing elbow 1/2 inch to 1/4 BSP with the 1/4 end pointing up the centre of the chimney, the thread is only in the end as it is a standard fitting.

Now the little end bush, the showman's little end is an AM181420.
the first 2 digits '18' are the outside diameter.
the second 2 digits '14' the inside diameter.
and the last 2 digits '20' the length.

If you can find a number in your paperwork similar to this then a bush can easily be sourced from a bearing supplier if STW are unable to help.
Just as a guide 1 off AM181420 from simply bearings is around £3:50 plus VAT but the postage is free. hope this helps.
Simon C

Many thanks for your reply Simon, all the info I need there.

Yes, I have a part No for the bush AM161216, I didn't realise that equates to the actual size of the bush so thanks for that. I will try and source one. Just been looking at turning one up and the prices of Phosphor Bronze these days

Try this for size Bartman
https://simplybearings.co.uk/shop/p120327/AM1216-16-Oil-Filled-Bronze-Plain-Bush-12x16x16mm/product_info.html
Simon C

Thanks Simon, ordered.

I think I owe you a beer or two!

Cheers
Pete.

Just one thing I forgot to mention Pete.
If the part number has an 'M' after it this usually means that STW have modified the standard bush.
The inside front wheel bushes for instance have a radius cut on the inside corner to accommodate the radius on the axle so these bushes would need a little work to fit them.
just a thought, in case you decided you would invest in other bushes for your engine.
Simon

Great, I'll remember that.

Many thanks again for your help and information, it's much appreciated.

Simon C wrote:Try this for size Bartman
https://simplybearings.co.uk/shop/p120327/AM1216-16-Oil-Filled-Bronze-Plain-Bush-12x16x16mm/product_info.html
Simon C

Nice link Simon C. One of those sites you didn't know you'd need which has lots of useful stuff on it. Already put an order in for non-related to Traction Engine build stuff.

Also remember folks. STW also hold spare parts including bushings

bartman wrote:

The engine has a knock when running, I think this may be coming from the little end bush so I took it apart and indeed there was play fore and aft on the wrist pin when fitted in the bronze bush of the little end which I suspect could be the cause of the knock I'm getting.

Dont get too carried away, clonks and knocks can be quite deceiving. My early Agri (read the very first control model   ) decided it sound like a diesel cement mixer at the first rally of the season this year that and total loss of chuff, it sounded like a wheezing ole man with considerable ring blow by

Spent Saturday lunch time re-shimming the mains, managed another flat on the big end wedge (will need a couple of thou off the big end shells if I want more) and buttoned it back up all while it was in steam  which to be honest is the best time if you dont mind handling hot bits.

Anyhow afterwards it was back to its sewing machine smoothness again, however I know I've got play in the little end and yet it never makes a noise. So be careful not to get led up the garden path when it comes to odd noises.

As for the wheezy stuff, we decided this was possibly the piston ring being stuck after its winter hibernation because during the afternoon the chuff started to return and after a short road run late in the afternoon to the pub (be rude not to) and on the return trip we had a decent chuff, back at site there was very little blow by the rings.

Found this Bartman when updating my roller thread brand new and no soot.
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Simon.