Whenever I restore anything, I pretty much run a Tap/Die over/through every fastener - most of the time it proves unnecessary - but as long as you do it carefully, it doesn't do any harm. But I am quite new to Seagulls, and one thing I have found is they get neglected terribly - neglect and salt water are a terrible mix. So I am even more careful to clean up every thread I come across and I think it is work well done. They go back together really well after the threads have been cleaned up.
This page contains a list of the Thread sizes from all the British Seagulls on which I have worked.
Be aware that this lists the threads as I found them, on the engines on which I worked - these may not be the correct ones for your engine. As you are probably aware, Seagulls get modified over time, and all my engines were bought used, so there is no guarantee that the threads I am quoting were the original ones for that model.
But having said that - they should be a pretty good place to start. You can use these values as a first attempt - but if your Tap/Die is resisting - STOP! And find out why, it may very well be the wrong thread.
Ideally, as this list grows, you will be able to look up the table for your model, and have a look for your fastener of interest.
If you can't find your model, look for one that may be similar - and check there.
Also of interest, right at the bottom of the page is a table containing the Torque Values for known fasteners.
Please - if you know any that I don't have listed - drop me a line and I will add them to the table.
These tables should grow with time. If you like working on Seaguls, Bookmark this page and refer to it whenever you need a threat size - And don't forget - if you have some that are not on this page - let me know via the eMail on the Contact page - Thanks.
| British Seagull Forty Plus MkII - Engine Code FPI22J0 | |
|---|---|
| Description: | Size: |
| Crank Shaft/Flywheel Dome Nut | 7/16in - 18 BSF |
| Cylinder head bolts | 5/16 - 22 BSF |
| Fuel Tank Studs | 5/16 - 22 BSF |
| Top Receiver for Water Cooling Flow rod. (double ended threaded brass stud) | 5/16 Whitworth Spanner |
| Generic Across all Models | ||
|---|---|---|
| Desc: | Size: | Torque: |
| Cylinder Head Bolts | 5/16in | 18 Ft/lbs |
| Cylinder Base Bolts | 5/16in | 18 Ft/lbs |
| Cylinder Base Nuts | 1/4in | 9 Ft/lbs |
| Crank Case Bolts | 1/4in | 9 Ft/lbs |
| Dome Nut for Flywheel | 7/16in | 24 Ft/lbs |