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Magneto shaft at standstill
#11
William,

From your questions I would kindly suggest you join an Austin 7 Club and buy a copy of the book Woodrow before going any further with the engine.

Tony.
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#12
I can turn the magneto drive by hand.

When I get home I will remove the timing gear cover. I will also post photographs and let you see the state of play inside the cover. I hope I will not have trouble in removing the crank nut and pully in the process.

It seems that a prudent step would be to replace all gears and keys given these items are problematic. I would not wish to experience a recurrence on another week end 250 miles from home.

Thank you all for sharing your knowledge and experience which is much appreciated.

Kind regards, William Cuddy.

TONY

Thank you for your advice.  Happily I have this publication - at home.

WILLIAM
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#13
You will probably find the problem by just taking off the dynamo housing and rotating the crank.
You don't need to take the crank nut off unless the gears need replacing.
If everything is original the bottom fan pulley is held on the shaft by a tapered pin,which of course will only knock out one way.
My bet,as Charles says is that the camshaft centre has sheared out.This is quite common on mag engine cars as the centre is weaker.
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#14
Photo 
[attachment=7804]GENTLEMEN
Better to be born lucky than rich.  Returned home.  Took off the front timing gear cover to discover the woodruff key for the crankshaft drive gear sitting on the sill.  


How it got out is something I am studying. Right now I am minded to think that it has something to do with the lack of a lock washer on the starting nut.  There is to me an ill fitting washer which does not look right.  

Also, I would have thought the crankshaft gear would be flush with the crankshaft itself but it produces out by a quarter of an inch.  

I have learned that the gears are in any event somewhat problematic and so I will try and replace all four plus keys.  

[attachment=7800][attachment=7801][attachment=7802][attachment=7803]

William Cuddy
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#15
Photo 
[attachment=7804]GENTLEMEN
Better to be born lucky than rich.  Returned home.  Took off the front timing gear cover to discover the woodruff key for the crankshaft drive gear sitting on the sill.  


How it got out is something I am studying. Right now I am minded to think that it has something to do with the lack of a lock washer on the starting nut.  There is to me an ill fitting washer which does not look right.  

Also, I would have thought the crankshaft gear would be flush with the crankshaft itself but it produces out by a quarter of an inch.  

I have learned that the gears are in any event somewhat problematic and so I will try and replace all four plus keys.  

[attachment=7800][attachment=7801][attachment=7802][attachment=7803]

William Cuddy
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#16
A local reckoned the cam gear on his car broke away from the centre after being meshed tight. Apart from wild cams and springs is this the main cause of failurre of that part? (not relevant to this case)
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#17
Hard to tell from the photos, but is that key correct? Looks a bit small from here. Apologies in advance if it is.
Peter
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#18
Might be time to replace the starting dog as well, that thread looks a little waisted.
Might be time for me to go to specsavers Big Grin cheers peter
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#19
You are a lucky chap - no big damage.
I personally would not change the gears as they have run OK as they are.
Clearly refitting the crank gear properly should do the trick, lock washer needed of course.
Changing the gears becomes a big job if you want to do it properly.
Whilst you have the crank gear off it might pay to release the tappets and check the end float on the camshaft as the engine has clearly been subject to compromise during assembly. 
I agree with Squeak the threads on the dog look cream crackered, therefore the dog needs replacement.
Re tightening the camshaft gear needs care, it needs to be tight but not overnight. Overtightening can crack the boss of the gear.
You might find the Red book a great help to you.
Stay lucky !
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#20
There is no way the key can get out without taking the gear off, either the key is not from the crank gear, or it fell out when the gear was last fitted to the crank (unlikely, but possible).
Does the gear turn relative to the crank?

Big washer shouldn't be there which would suggest the starter dog didn't screw fully home, and was bodged using the washer, when you get a new starter dog make sure it screws in fully and freely.

Obviously been some poor quality work been carried out in that area in the past.
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