Dynamators Gear Wear & Reliability

[jansens]

Yes, I was wondering what modern tuned exhaust meant too?

[Charles Levien]

Andrew, thanks for coming up with another good reason to stick to 6v.

Yes — and use electronic ignition. Plus overhauled dynamo and LEDS.

[Alan]

Well I’ve a 4into1 exhaust with pipes that just happen to be the correct length and that’s acceptable. Not so sure what would happen if I used 4:2:1 and cross over inlets. Don’t knock the VSCC, they are trying to keep cars in period when it would be so easy to incorporate modern technology.

[jonblob33]

A bit more on my dynamater. Had news today that the supplier has agreed to replace my dynamater due to finding an internal fault. However when I examined the drive gear on the distributor, I found it badly worn even though it has done less than 200 miles after a full rebuild by a well known person. Both gears on the dynamater are original Austin gears in good condition. Just wondered if anyone else had the same problem. Debating if I should revert to original setup with 2 brush 12v dynamo & electronic regulated. Will welcome any advice or suggestions.

[Dirk73]

Although it's already been said, i can 2nd the gear design problem on the Dynamator, after 50 miles it had chewed nearly 2mm off the inner edge of the cam gear.
The bevel angle on the Dynamator gear appears to be shallower than the original.

Anyone who's bought one with the gear, as Ruairidh said, swop the dynamo gear for the original one.

Accuspark MD "We acted on information supplied to us from the A7 owners club that the unit had been tested and was correct for production.
We have had no information regarding any specific problem with the unit, or cause of failure, In fact we have information that gear problems are not uncommon on this vehicle due to the large variation in tolerances with original gears. Subsequently we are not in a position to accept any liability for any consequential loss."
 
But does the angle of the timing gear bevel vary on different Austin 7 years and production batches?  

 They now sell it without the gear. Apart from that mine appears to function well.

[Tony Press]

"we have information that gear problems are not uncommon on this vehicle due to the large variation in tolerances with original gears. Subsequently we are not in a position to accept any liability for any consequential loss."

Am I missing something - I do not remember hearing about the Austin Seven having 'a large variation in tolerances with original gears'  other than matching the timing gears to the crankcase - I didn't think there were any special markings on the dynamo drive gears to match it to the camshaft gear.

As usual I am obviously behind the times.

[Charles P]

"we have information that gear problems are not uncommon on this vehicle due to the large variation in tolerances with original gears. Subsequently we are not in a position to accept any liability for any consequential loss."

Am I missing something - I do not remember hearing about the Austin Seven having 'a large variation in tolerances with original gears'  other than matching the timing gears to the crankcase - I didn't think there were any special markings on the dynamo drive gears to match it to the camshaft gear.

As usual I am obviously behind the times.

Never heard of "large variation" issues with dynamo gears either Tony. 


Charles

[Austin in the Shed]

The problems with Austin seven gears is/was bad mechanics chipping the teeth or running on treacle instead of oil.There is slight variation between the crank and cam centres but the dimension between the cam centre to the top face of the crankcase on all the ones I have measured have been very accurate,that's why the dynamo gears  are one size.
I believe there are 2 different pressure angles of 14 1/2 and 20 degrees on that tooth form,or they haven't been cut at 45 degrees,I've not seen one to comment.

[Tony Press]

Wasn't there an earlier post which pointed out the angle difference between the original gear and the new gear ?

Or am I imagining this as well ??

[Stuart Giles]

Wasn't there an earlier post which pointed out the angle difference between the original gear and the new gear ?

Or am I imagining this as well ??

This post?

http://www.austinsevenfriends.co.uk/forum/showthread.php?tid=1169&pid=14084&highlight=dynamator#pid14084