4G timing case insert

Singles, twins and fours.
Pete.Silson
Posts: 43
Joined: Fri Sep 16, 2016 11:31 am
Location: Wanborough, Wiltshire, UK
Contact:

4G timing case insert

Postby Pete.Silson » Sat Aug 12, 2017 9:45 pm

I have recently acquired a old derelict 4G engine in need of some tlc. The timing chest has suffered some damage and the hole in the timing case for the magneto shaft was very ragged. On closer inspection I found the remains of a threaded insert in the hole. The insert appears to be made of alloy with a 1-1/8" 26 tpi thread. My later 4G engine appears to have something similar but made of steel. I can't find any mention of it in the Ariel parts book. Can anybody point me in the direction of a source for a replacement or is this going to be another "make a new one yourself" job?
1a.JPG
1b.JPG


Pete

roger.fellows
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 402
Joined: Tue Feb 21, 2012 8:32 pm
Location: S.Cumbria UK
Contact:

Re: 4G timing case insert

Postby roger.fellows » Sun Aug 13, 2017 6:43 am

Sorry, I know nothing of the 4G, but the 'rubber' insert at the top of the case looks interesting. Is that standard or some sort of modification?

Roger

Pete.Silson
Posts: 43
Joined: Fri Sep 16, 2016 11:31 am
Location: Wanborough, Wiltshire, UK
Contact:

Re: 4G timing case insert

Postby Pete.Silson » Sun Aug 13, 2017 8:57 am

Roger

The fibre rubbing strip is standard on a 4G. It is rivetted to the inside of the timing case along the long top run of the timimg chain.
timing chain.JPG

Pete

roger.fellows
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 402
Joined: Tue Feb 21, 2012 8:32 pm
Location: S.Cumbria UK
Contact:

Re: 4G timing case insert

Postby roger.fellows » Sun Aug 13, 2017 10:46 am

Thanks Pete. Ahhhh - I see now, the view in the second photo I saw as a slot in the alloy along the top run. Where should I go?

stuart.wilby
Posts: 33
Joined: Mon Dec 30, 2013 5:21 pm
Location: Wakefield
Contact:

Re: 4G timing case insert

Postby stuart.wilby » Tue Aug 15, 2017 8:37 am

Looks like a repair after a chain loss, your halfway there, the casing is threaded.
The rub strip is to minimise chain whip and silence the action, not great design, the residue from this can only go into the oil in small dust/fragments, and inevitably into the oil galleries, probably responsible for the crankshaft blocking up over a period of time, if it breaks up in big lumps, the chain will suffer.
1948 4G Square.

User avatar
paul.jameson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1100
Joined: Wed Oct 12, 2011 3:04 pm
Location: Herefordshire
Contact:

Re: 4G timing case insert

Postby paul.jameson » Sun Aug 20, 2017 10:39 pm

Pete,
If you look in Waller, he mentions the danger of damage to the flange around the magneto drive hole on a 4G and says it can and should be built up with weld. An easier solution is to fit an insert, particularly if the damage is severe. I think what you have is a selection of solutions to the problem. The best answer is an aluminium insert but centring it accurately may be a problem. Steel inserts will tend to come loose due to the greater expansion of aluminium when heated - and the Square Four gets hot !
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), 54 4G Mk IV (project), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser.

User avatar
CFritz
Posts: 12
Joined: Wed Aug 23, 2017 1:14 pm
Location: Huizen, the Netherlands
Contact:

Re: 4G timing case insert

Postby CFritz » Wed Sep 06, 2017 1:20 pm

friend of mine turned from nylon (tested heat resistance first) a bush that exactly fits between the magneto chainwheel and the timing case hole. centered it well by loosening the magdyno, pushing the bush in and retightening the mag. the ruined hole rim served well to keep the bush from turning. works a treat.
chielzelf

1938 4G 1938 NG 1950 VB and Steib 2006 cat called Scooter


Return to “Four stroke”

Who is online

Users browsing this forum: No registered users and 4 guests