Rebuilding a Stuart Turner P5

Most of the load should be taken by the taper, the key being primarily for location purposes - I would try and make good with one of the metal loaded epoxy putties available. Does the P5 have the taper on the crankshaft itself or on a separate split sleeve like some other S-T's?

Peter... Be very carefull, if you weld a crank shaft on one side it can distort the shaft by the rapid expansion of the metal and you would end up with a hefty door stop.

Rgds bob

Welcome to the News Group & you've come to the right shop for friendly advice ;o))

It helps a lot if we can judge the extent of the damage before comment, so is it possible for us to see some photos?

They can't be seen here, but many of us have Webshots albums - me for instance & I'd be happy to put a few up for you then publish the URL here.

Regards,

Kim Siddorn

Can you machine a new keyway in a different position? That way you save all the problems associated with welding a crankshaft.

John

Kim,

Thank you for the welcome.

When I get a chance (I run a miniature railway as a hobby - see

I will get some photos up on the website. I have just finished re-assembling a locomotive following a boiler repair and I am off to Japan (on business for a week) from Sunday, so there isn't much time at the moment.

I have a load of spares from Fairway marine, including a new collet (the original was split) and is probably what started this damage. I originally bought this engine to keep as a set of spares for another P5 that's installed in a large Petrol-Mechanical engine (Hudswell Clarke - "Junin") but in the end I couldn't bring myself to strip it, I decided to repair it and use it as a power source for a minaiture railway locomotive!

Cheers for now

Peter

In my far-off youth, I raced 250cc karts for some years. One engine had a crank on which the flywheel had become loose, & danced on the shaft -- taking big chunks out of the taper & the keyway slot.

SWMBO decreed that all monies must go on nappies, & I had no engineering skills or mates in the trade. Knew I was better with a plastic strip than a welding torch, so filled all of the damage with a mix of 50/50 Araldite & alloy filings. Big file smoothed all the taper, & swiss files sorted the keyway.

Lasted for over 20 race meetings without any problems at all. Still working well when I stopped racing 3 years later........ Even stripped it out of curiosity at the end, & there had been no further creep or damage at all.

The originality anoraks would have had a field day, but we were just simple, broke, racers trying to have reliable sport ......

Colin

Many years ago I was involved in stock car racing as a "mechanic". One racer "Yogi Bear" raced a Skoda! He couldn't get high compression pistons for it so he used the 50/50 Araldite/alloy filings mix to fill the depressions in the stock pistons. It worked for about 5 races, by which time most of the mix had gone out of the exhaust pipe. He won many races like this but I was never convinced that it was the Araldite that did it, he was a animal behind the wheel.

Easy way to rectify this problem would be to true up the damaged keyway in the crank, with something like a 1mm cutting disc, then make a key to fit exactly in the wider keyway, and then reduce the thickness of the upper part so it fits the crank.

This method is tried and tested on comp motorcycles, and while taking longer to do than messing around with aralaldite, does work very well.

k