Broken Spigot!!

[Den 08]

well bad day yesterday, on stripping an engine found this inside is this usable or will it need relining or is it scrap
bought engine last November so that's that, ts1 humiliator complete. totally pissed off your thoughts please gentlemen.
Den

[bristolmod]

I did a big conversion from a 150 to a 200 some years ago.

The guy that did the rebore remarked how thin the spigot then was and asked if I wanted it trimmed back to the first "step" on it.

This he did and the conversion ran as sweet as a nut for many thousands of miles thereafter.

Worth tidying up IMO and trying.

Chris

[Den 08]

tbh i am kinda hoping it will run.
i have had a good look there is no other obvious marks or cracks.
was thinking about crank pressure will it effect running, tickover etc
would the piston slap about?
Den

[soullad]

why not think about getting it lined?
approx £200, and you can now shift the boost port a tad more centrally, to help with your ring ends not falling into said port. I assume you've got the KX piston conversion?

[Adam_Winstone]

Not wanting to play the same old record again but what type of cylinder studs are you running it with? The only difference between this and other spigot failure that I've seen because of increased side-loadings that resulted from fitting 'fat studs', rather than allowing the spigot to control the barrel to casing alignment, is that other spigot cracked at the 90 degree machining of base gasket face to spigot upright (cracking tends to crack at the stress point; the corner).

There's not much else that will cause a side-loading on the spigot than a misalignment of studs + stud holes + spigot. Please note that any one of these might be at fault here (if indeed this plays any part of your barrel's failure!) so I'm not blaming anything... but do consider these factors as way too many people are finding that they are 'knocking a cylinder home' or 'tightening head nuts down in order to force the cylinder to seat correctly', both of which put big side-loadings on the spigot and can cause them to crack through. Every cylinder should slide home without any effort, some cylinders do have poorly positioned stud holes, which is compounded by trying to fit any stud that is a larger diameter than standard.

Consider all possibilities. Good luck finding the cause.

Adam

[Den 08]

Not wanting to play the same old record again but what type of cylinder studs are you running it with? The only difference between this and other spigot failure that I've seen because of increased side-loadings that resulted from fitting 'fat studs', rather than allowing the spigot to control the barrel to casing alignment, is that other spigot cracked at the 90 degree machining of base gasket face to spigot upright (cracking tends to crack at the stress point; the corner).

There's not much else that will cause a side-loading on the spigot than a misalignment of studs + stud holes + spigot. Please note that any one of these might be at fault here (if indeed this plays any part of your barrel's failure!) so I'm not blaming anything... but do consider these factors as way too many people are finding that they are 'knocking a cylinder home' or 'tightening head nuts down in order to force the cylinder to seat correctly', both of which put big side-loadings on the spigot and can cause them to crack through. Every cylinder should slide home without any effort, some cylinders do have poorly positioned stud holes, which is compounded by trying to fit any stud that is a larger diameter than standard.

Consider all possibilities. Good luck finding the cause.

Adam

I thought the studs looked thick and did have to give a bit of a push (wack) when offered back on, will check tonight
the piece was missing when took apart so I assume the bloke sold it me like it

why not think about getting it lined?
approx £200, and you can now shift the boost port a tad more centrally, to help with your ring ends not falling into said port. I assume you've got the KX piston conversion?

I am thinking about relining who would you recommend I am in Bristol?

I suppose bottom line, is it worth using as is?

[Adam_Winstone]

If the broken spigot was not being mashed around the crankcase mouth then this has been stripped at some time, and there is no way of saying for sure what the cause of the damage was... it may simply have been dropped in the workshop/garage! Do have a look for causes though as they might point you in an 'informed' direction. You should consider likely options but you certainly will not be able to point the finger of blame... other than at the bloke that previously built it with the part missing

Yes, it'll run... but you could well get piston slap if it allows the piston to rock in the bore (was it slapping before you stripped it?).

Adam

[Den 08]

haven't ran it yet Adam, I thought I'd strip it just have a look at gaskets etc as the bloke said he'd had it while and not used it himself (live and learn eh NOT)

[Darrell Taylor]

id run it after inspecting everything else ,the centre line of the spigot will take most of the skirt load ,most race cylinders are designed with a similar section missing to aid flow

[Darrell Taylor]