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Re: Whitish smoke from crankcase breather

I'd be interested to know what you find. The white smoke might be from oil that is blowing past the piston, perhaps? You mentioned a loss of compression, so it's not impossible. Do you have white smoke in the exhaust?

Allan

email (option): allanmatchless@yahoo.com

Re: Whitish smoke from crankcase breather

Allan & others

I've taken off the barrel & it's a sorry sight. There's major damage to the piston in the right hand gudgeon area, with little of the circlip left. Rings are broken & jammed. This has worn a deep vertical groove in the liner adjacent to the gudgeon.
The gudgeon pin rocks badly in the small end bush.
I'm also worried about the big end. There's no vertical play but the rod can be rocked from side to side (as opposed to any sideways movement of the whole rod). Is this an indication of big end failure?

I'd be grateful for any opinions as to what may've actually gone wrong here.

I'm very angry about this "rebuilt" engine but the gentleman responsible now resides on the opposite bank of the Styx & is uncontactable by any means in my possession.

Re: Whitish smoke from crankcase breather

Well the slightly good news is that there will always be some sideways rock in the conrod. As long as you can't feel any lift at all, they're fairly bullet proof.

So time to do a top end overhaul. Ron

email (option): ronpier@talk21.com

Re: Whitish smoke from crankcase breather

That sounds like a classic case of the gudgeon pin coming out due to a missing or incorrectly fitted circlip....There are also different circlip designs (with appropriate groove) so an incorrect clip is a possibility....

I spent about 20 years running my own business rebuilding BSA engines and I can safely say previously 'rebuilt' engines represented a measurable part of my work...Sadly it's the case that many of these 'engine rebuilders' don't know what they're doing...

It is likely you will need to fit a new liner but only accurate measurement of the bore will determine that...Liners are still available...I think John O'Brien from this forum has small end bushes available...The secret with these in a sidevalve engine is not to make them too close a fit after reaming...The piston should fall freely from side to side under its own weight but with no up and down clearance...

Big ends which have done some miles will always have a degree of 'tilt' of the rod...Knowing how worn they are is really down to experience over a number of engines unfortunately...There is no measurement for that...If there is no up and down play in the big end it may be OK to go again but determining its potential lifespan isn't possible..The only true way to know its condition is to strip it....So really it's down to how much you want to do (and spend) at this point and how much of an optimist you are...
However, bear in mind that all those bits of metal from the rings, clip, bore and piston haven't evaporated...they are still in there somewhere!....Ian

email (option): ian@wright52.plus.com

Re: Whitish smoke from crankcase breather

A well known Enield specialist has just had a circlip come loose. The supplied circlips were marginally too big for the piston groove

email (option): jeremy@clogmaker.co.uk

Re: Whitish smoke from crankcase breather

I've seen NOS BSA pistons for sale on ebay with circlips I know to be the wrong ones...It seems sellers just add any circlips to make a piston complete if the clips happen to be missing...Badly overweight gudgeon pins aren't unknown either, same story there....Ian

email (option): ian@wright52.plus.com

Re: Whitish smoke from crankcase breather

Thank you, gentlemen, for these responses.
A major stripdown is called for. For now that means saving my pennies.

Re: Whitish smoke from crankcase breather

White smoke also means "habemus papam"... 😁

email (option): wd.register@gmail.com

Re: Whitish smoke from crankcase breather

We get asked all the time for gudgeon pins and circlips for unknown pistons. It can be a dangerous game.

Mark

email (option): pes.sales@btconnect.com

Re: Whitish smoke from crankcase breather

Jan
His Holiness is welcome to intercede on my behalf in the matter.

Mark
I see what you mean, this engine has been slung together using whatever internals were lying around.

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