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+--- Thread: Sump studs size and thread (/showthread.php?tid=7980)
Sump studs size and thread - John Mason - 29-08-2022
Hello all just a quick question. What is the size and thread type (I think it is BSW but not sure). Of the studs that hold the sump on. I need to be sure in order to get the correct thread inserts to make a repair. Thanks in advance.
John Mason.
RE: Sump studs size and thread - bystander - 29-08-2022
They are not studs, but deep headed bolts, 1/4 whit thread. An alternative is to drill and re-tap 5/16 whit for oversize bolts which are available with with same size heads as the original 1/4W.
RE: Sump studs size and thread - JonE - 29-08-2022
did these change from BSF to BSW over the course of the Seven? Just wondering as I have some bolts of different thread.
RE: Sump studs size and thread - John Mason - 29-08-2022
Hello Bystander, Apologies for my ignorance I was under the impression that bolts only had threads at the end of the shaft and studs were threaded all the way to the head. Thank you for the suggestion of tapping out to 5/16 and using the larger diameter bolt. Can you advise where you can get the 5/16 whit with the 1/4 whit head. Once again thanks for everything.
John Mason.
RE: Sump studs size and thread - Parazine - 29-08-2022
(29-08-2022, 07:49 PM)JonE Wrote: did these change from BSF to BSW over the course of the Seven? Just wondering as I have some bolts of different thread.
Early (1922 - 25 I think) engines had 1/4" BSF sump bolts, thereafter 1/4" BSW.
RE: Sump studs size and thread - Austin in the Shed - 29-08-2022
For the price of the oversized bolts you could buy a helicoil kit and get the threads back to standard and never strip them out again.
RE: Sump studs size and thread - Ruairidh Dunford - 29-08-2022
Oversize sump bolt and washer.
https://www.theaustinsevenworkshop.com/search?query=Sump+oversize
RE: Sump studs size and thread - bystander - 29-08-2022
Effective cost and amount of work required would depend on how many need doing. If it was the whole lot then helicoiling as suggested would probably be the way to go. If only a few then tapping oversize might be preferred?
Incidentally besides early mag engines, the Austin 10 had the same screws, but with the BSF thread.
RE: Sump studs size and thread - Chris KC - 29-08-2022
bolts only had threads at the end of the shaft and studs were threaded all the way to the head
A bolt has a plain shank, and a machine screw - which these are - is fully (or almost fully) threaded along its length. A stud is threaded at both ends, and has no head.
RE: Sump studs size and thread - David Cochrane - 29-08-2022
Another supporter of thread inserts (helicoils) - a better engineering solution than oversize bolts or stepped studs IMHO. I bought kits as & when I needed them and they're great to have on the shelf especially when you get that sinking feeling of a 'soft' 14th sump bolt...
David