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Re: 27-1239 Engine Shaft Rivet

Successfully riveting the mainshaft flange to the flywheel I found quite difficult...The rivet material is quite hard which makes hand riveting awkward. I'm guessing that in the factory at least, they were machine riveted...Years ago I made a jig to hold the flywheel/ mainshaft to make the rivetting process easier...However, the original rivets I acquired from Russell Motors varied in both the shank length and the head thickness...
The former is obviously important to achieve a properly formed rivet..The latter problem I overcame by fitting a bolt with a hardened roller pressed into the end for each rivet so that they could be individually tightened against the back of the rivet head ....

That said, the rivet material made a hard, sure blow with a fairly lumpy hammer and suitable punch a definite requirement...

Frankly, it was never a job I relished and generally avoided if possible....Some competition machines had the rivets replaced with high tensile screws/bolts after tapping as required and I'm told it was a common modification in Gold Star circles back in the day...
I've never tried it myself and thus haven't investigated the method at all but it seems at first sight to be a good idea...The fit of the shaft to the flywheel is doing the bulk of the work, the rivets serving to ensure the shaft stays in place after fitment...Regarding alignment of the holes I used lengths of silver steel inserted into the rivet holes to keep things in line during initial fitment.....

These days only my M20 retains an original crank...The other three all have pressed up ' modern' cranks, though the original cranks generally don't give any trouble in standard engines....Ian

email (option): ian@wright52.plus.com

Re: 27-1239 Engine Shaft Rivet

Thanks Ian, you convinced me that the so-called original rivets were not the way to go.
I tried to close a couple up and it was not a nice experience.
With a lot less effort than I expected I reprofiled the heads of some rivets we keep in stock.
The only real pain was that they were about an 1/8" too long.

Below the pictures of the shaft and rivets in place.
I used a course polishing mop to debur the heads.
Followed by an ultra-sonic bath.

Mark



email (option): pes.sales@btconnect.com

Re: 27-1239 Engine Shaft Rivet

That looks great work mark - painful but great

Have you ever swapped out the flywheel thrust washers fitted - they are secured with rivets too ?
Br
Jo’b

email (option): jonnyob1@googlemail.com

Re: 27-1239 Engine Shaft Rivet

Thanks John,
I haven't, but I can't see an issue with it. Yes, they are riveted too.

Mark

email (option): pes.sales@btconnect.com

Re: 27-1239 Engine Shaft Rivet

This should be a golden opportunity for any rivet counter...How many rivets are there on an M20?..(it's a lot more than you would think)..Ian:relaxed:

email (option): ian@wright52.plus.com

Re: 27-1239 Engine Shaft Rivet

Just in case anyone has the same problem with the shafts in their M20 cranks I'm happy to offer a repair service.

Shafts and rivets in stock

Mark

https://pesltd.uk/?product=66-0644
https://pesltd.uk/?product=66-0640

email (option): pes.sales@btconnect.com

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