Presentation and crankshaft problem

Started by Paul Davy, December 28, 2013, 05:40:56 PM

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VicYouel

I seem to have missed reading this section of the forum....... as for torque level....... you simply learn with experience.  Possibly 20-25 foot pounds?

Vic

Paul Davy

Hello,

I told you in previous messages my (huge) problems with the crankshaft of my Sunbeam Model 9 (1932). The damages were important but the crankshaft is repaired now. I have to re-assembling the engine and I have a question about this operation. Do you know the normal tightness torque of the sleeve nuts which retain barrel and cylinder head on the crankcase ? I am afraid to screw down these nuts too tightly (or at contrary not enough).
Thanks a lot for help.
Best regards.
Paul

Paul Davy

Hello John,

Thanks a lot for your answer about the mainshaft pinion and for your offer concerning the main bearings.
I checked the up and down play at the level of the conrod. It's correct. The problem is a really important side play : it seems like the flywheels and crankpin are not tighten ! It's incredible, but 3 weeks ago the bike was on the road and, apart this light rattle , everything looked right. The overall crankshaft stayed in place only by the guidance of the conrod and piston in the barrel. I don't dare to imagine what would happen if I had continue to ride an other time..
Sorry I did a mistake on our blog adress. Of course it's : http://motosanciennes.canalblog.com
Best regards.

Paul

singleminded

the mainshaft pinion is keyed to the mainshaft.If i remember correctly the nut is a lefthand thread,the theory is that the nut will try to tighten against the rotation of the crankshaft..
As you have the engine out of the frame have you tried lifting the conrod to see if there is any up and down play in the bigend?
Or tried lifting the mainshaft to see if the main bearings are shot..If you need new main bearings and cannot source them locally I can give you the address of the people who supplied mine..John

Paul Davy

Hello Vic,

Thanks a lot for your welcome. By the way, I live not very far from Cherbourg, in the country, in a part of Cotentin called "La Hague". If you come again in France by Cherbourg, it would be a pleasure to see you. I belong to a small local Vintage and classic bikes club named "Les Vieux Pistons du Cotentin" (our Internet blog is http://mtosanciennes.canalblog.com).
Concerning my Model 9 bottom engine I will bring it in the beginning of january to a specialized workshop located close to Paris. The mechanic asked me not to dismantle the crankcase myself so I will have a precise idea about the damages only after the opening.
May be you (or an other club member) can answer to this question : during the dimantling of the engine I didn't succeed to retire the small pinion at the timing end of the crankshaft (this small pinion drives the two timing pinions). I didn't find details in my documentation but, may be, this pinion is a left thread ?
Thanks a lot for your help.
AmitiƩs.
Paul

VicYouel

Welcome Paul,

I have just had my Model 9 bottom end repaired by Alpha near Birmingham. Let me know more details please.

Have ridden in France more than once via Cherboug.

Amities

Vic Youel (vicyouel@gmail.com)

Paul Davy

Hello, I am a new comer. May I introduce myself : my name is Paul Davy and I'm 74 years old. I'm french (sorry for poor english) and live in Cotentin. I own several french and british bikes from 1921 up to 1969. Among them a Sunbeam Model 9, 1932. I own this bike since 2009 and, unfortunately, I have some technical issues now. I was seeking about a light but tenacious noise and finally found a lot of play in the crankshaft somewhere between crankpin and flywheels. The engine is dismantled (crankase not open) and I will send later a new message on the forum about some technical details. May be somebody could answer..In advance thanks a lot for answers.
Kind regards.
Paul