Help needed with SC46 parts.

[Cliff Bastow]

I am hoping someone on here can help please!

I have managed to snap the pin from the crankshaft on one of my Sc46 engines. Do not ask how please!

The engine is otherwise in good condition so I would like to get it running again.

The problem is they seem unobtainable now. I am hoping someone one here might have one to sell or an non running engine I can break for parts.

It is a late model s type and the part no is S40210.

hopefully.

Cliff

[Low pass Pete]

Try Just Engines.  I think SC were the same as ASP engines and Just Engines were supplied and supported/repaired by them.

 

Edited March 28, 2021 by Low pass Pete

[Martin Arnold 1]

Yes ASP, SC and Magnum were all made by Sanye in China and are effectively the same motor, so a crankshaft for any of those will do the job, however it would appear there is no stock of them.

 

Reckon your best bet is a second hand engine, think the crank is the same on the 40 and 46 so either will do, there are quite few on Ebay for around £40 (see below), but you may find one cheaper.

 

https://www.ebay.co.uk/itm/SC-46-2-Stroke-NITRO-GLOW-engine-AND-MUFFLER-RC-model-plane-SC-ASP-CHINA/274635815117?hash=item3ff191f8cd:g:q8oAAOSwqstf8uaZ

Edited March 28, 2021 by Martin Arnold 1

[Martin Arnold 1]

Here is a 40 in bits for £25

https://www.ebay.co.uk/itm/ASP-40-2-Stroke-RC-Aircraft-Nitro-Glow-Fuel-Engine-Incomplete-For-Spares/124645545246?hash=item1d0574151e:g:oXgAAOSw-TlgVpfp

[Cliff Bastow]

I have already tried the just engines route and they do not have any stock for any of these makes.

Martin the engine you sent details of has the wrong crank. It is more like the early mk1 SC engines. The later s type engines had a front bearing with a smaller inner bore so the crank is thicker in this area and it also has two flats milled in to match the slots in the prop driver so I need a later sc engine with the square head. These were know as the s type engines.

I believe the cranks were also the same on a 51 but not certain of that.

Edited March 28, 2021 by Cliff Bastow

[Cliff Bastow]

Really hoping someone can help, otherwise I am a bit stuck.

[Cliff Bastow]

These are the two Sc style crankshafts. The one on the right is the type I need.

Thanks Cliff.

[kevin b]

Are the early type bearings no longer available as well ?

I would have thought they were a standard size.

Judging by the look of your "broken" crankshaft I would think that the rest of the engine is probably in a similar condition.

Is it worth repairing ?

The same amount of stress that broke the pin would also have acted on the other end of the conrod.

Replace the crank and the next time you run it the top end could break.

That is my experience with repairing engines (not just models).

[Denis Watkins]

I agree with KevinB on this one, 

One of the lads flying the SC had one break a pin in the air, that went with heck of a " thwack" and dead sticked with the prop " windmilling " freely.

A couple of weeks later he arrived back at the field with the new pin installed in the repaired motor which lasted about 10 minutes in the air, due to an audible clunking noise coming from the motor. 

Turning by hand you could feel binding for each revolution. It was relegated to the spares box from then.

 

Just be mindful, as suggested earlier, that some stress, during and after fracture, was transmitter through the motor.

 

 

[Cliff Bastow]

Thanks for the advice chaps. Normally guys I would agree with you but as I have already stated the engine is in good condition. It was not running when I broke the crank pin anyway.

I just want to know if anybody can help with parts.

I am a multiskilled engineer with over 40 years experience so I know what I am doing.

Thanks again Cliff.

[Denis Watkins]

Consider making a pin from an appropriate sized drill bit Cliff, ground and polished

If no pins become available

I have done it in the past

[Cliff Bastow]

That is not a bad idea Denis and had actually crossed my mind but unlike the earlier style cranks that seem to have a seperate pin, on mine it appears to have all been machined in one piece. It is snapped flush with the face of the crankshaft. I suspect it is hardened so it might be difficult to drill the old bit out.

Cheers Cliff.

[Denis Watkins]

If you have not progressed Cliff

Have just come across hardened, ground steel pins on ebay, both metric and imperial sizes

It is a long shot that the correct diameter is available off the shelf, but worth a try