Water Branch Top Stud

[bob46320]

I am about to re condition a spare LP Cylinder head and need to re-tap the single snapped off 5/16" stud for the water branch. Is the cylinder head tapped 5/16 BSF or the coarser 5/16 BSW ?  The part number for the stud is listed as SUP-C01 in the old spares catalogue.
Any preference in making the stud in stainless instead of mild steel ?

[Howard Wright]

Hi Bob

BSF on the head I’m just re conditioning. Surprisingly it doesn’t need much work and the water branch stud came out quite cleanly.

I think I might use stainless when I replace it.

Cheers

Howard

[bob46320]

thanks Howard, The head which is currently on the engine had a bolt welded to the cast iron head - looked awful, which is now very badly corroded, so the winter overhaul will include replacing with a spare head that I have, once I have cleaned it up etc.

[David Cochrane]

They're available in stainless steel from A7 Components and the Seven Workshop.

[bob46320]

Thanks for the "sales" ad, but quicker to make one thanks, also post to France will be getting ridiculous after dec 31

[Robert Leigh]

When I do this particular renovation I use a stainless steel stud, and a brass or stainless dome nut with a fibre washer underneath which completely eliminates any water creeping up the thread. Also I loctite the stud into the head which reduces rusting of the cast iron and preserves the thread.

[Tony Betts]

hi Bob,

dont worry, there are other suppliers who do the stainless studs so much cheaper. it more than makes up for the rissing postage costs

i remember myself and wayne rushin around 28 years ago, being the first of the main dealers to offer stainless studs for the water manifolds. its good to see we got things so right. the rest of the suppliers followed suite.  you`re welcome.

it was a 50/50 decision at the time between stainless and brass. stainless sounded good.

easy enough to make yourself bob.

i also use a dome nut, and fibre washer.

but i copied that from dave flake at quarry engineering. it looks a bit flashy for a seven. but works very well.

tony

[bob46320]

Now there's a funny thing, my LP head is tapped 5/16" x 18 tpi, that makes it 5/16" BSW. Now it could be that in the past, someone bodged the thread from BSF to BSW, but the BSW tap cleaned the thread up without any stiffness being noticed.

[John Mason]

Bob I am not surprised by your BSW thread as it screws into cast iron. I have always been led to believe that a course thread is stronger in anything cast.

John Mason.