My 46 SQ4 is finished - or so I thought

Singles, twins and fours.
User avatar
john.davies
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 135
Joined: Mon Nov 30, 2015 9:33 am
Location: Bath, UK
Contact:

Re: My 46 SQ4 is finished - or so I thought

Postby john.davies » Fri Aug 16, 2019 12:51 pm

Thanks Pete, I will talk to my local friendly machinist to see what he thinks. I want to try and find a solution that entails as little stip down of the engine as possible if I can.
Image 1937 Panther M100 Rigid, 1946 Ariel Square 4 Rigid / Girder, 1952 Norton Model 7, 1953 BSA A10 Super Flash (WIP), 1958 BSA C15, 1961 Triumph T120R

User avatar
paul.wirdnam
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 574
Joined: Fri Apr 08, 2011 7:50 am
Location: Okeford Fitzpaine, Dorset, UK
Contact:

Re: My 46 SQ4 is finished - or so I thought

Postby paul.wirdnam » Fri Aug 16, 2019 2:47 pm

John,

A couple of photos from a crankcase that apparently has never been used....came from Healey works I think. The hole measures 0.935"

When I restored my Sloper in 2012, I had a similar issue and didn't want to dismantle the engine etc. In the end, I resorted to carefully opening up the damaged hole with a file to suite a modern garter seal. I kept checking that the hole was circular and central to the magneto shaft. Finally glueing the Viton* seal in place with Loctite 480 (the one with rubber). I'm still very pleased with result, the seal is firm after 7 years and doesn't leak.

*I initially used a std. nitrile seal, but they go hard quite quickly with the high temperature. Viton is much better.

Looks like I need to do this on my 4G....thanks for the heads up!

IMG_20190816_143410-01.jpeg


IMG_20190816_143422-01.jpeg
'28 Model B (future project), '30 Model F, '31 SF31, '35 4F, '38 VB (abandoned project), '39 4G (current project), '46 VH, '48 KG

Paul

User avatar
john.davies
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 135
Joined: Mon Nov 30, 2015 9:33 am
Location: Bath, UK
Contact:

Re: My 46 SQ4 is finished - or so I thought

Postby john.davies » Fri Aug 16, 2019 5:42 pm

Hi Paul, I thought you might need to do something when I looked again at the pictures of your 4G project. What size seal did you use for you sloper. I know the external diameter will depend on what size flange hole mine is but internal and thickness would help. As we said the last time we spoke, these bikes seem to be fighting us all the way. Even the V5C has got lost between the post office and the DVLA when I had to change taxation class whilst taxing it so they are now raising a case to find out what has happened. Cheers, John
Image 1937 Panther M100 Rigid, 1946 Ariel Square 4 Rigid / Girder, 1952 Norton Model 7, 1953 BSA A10 Super Flash (WIP), 1958 BSA C15, 1961 Triumph T120R

User avatar
paul.wirdnam
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 574
Joined: Fri Apr 08, 2011 7:50 am
Location: Okeford Fitzpaine, Dorset, UK
Contact:

Re: My 46 SQ4 is finished - or so I thought

Postby paul.wirdnam » Fri Aug 16, 2019 6:04 pm

Hi John,

Yep...3 too many cylinders without a doubt!

We're in luck I think. I still have 2 new Viton seals that I used on the Sloper and I've just dug them out. They are 20 x 26 x 4...and having just measured the sprocket boss diameter (22.8mm) and the crankcase hole diameter (23.7mm), these look perfect for the 4G as well. As you can see, I still have some some sort of oil return scroll on the sprocket boss, but I'll machine this down to 20mm and polish up the surface for the seal. Should work fine.

BTW: with such a narrow seal, these do not have the circular spring in them, but I don't see that as a problem.

IMG_20190816_175153-01.jpeg


IMG_20190816_175137-01.jpeg
'28 Model B (future project), '30 Model F, '31 SF31, '35 4F, '38 VB (abandoned project), '39 4G (current project), '46 VH, '48 KG

Paul


Return to “Four stroke”

Who is online

Users browsing this forum: No registered users and 29 guests