An early stuart 10H restoration/ repair

[half whitParticipant @half-whit]

Hi All,

Some time ago I acquired an old, very early Stuart 10H. Not quite complete, about 85% and needing much tlc and some detailed repair work.

I appreciate that original drawings may well be hard to get, even non existent but regardless I  should be able to complete a presentable and working engine.

The eccentric rod has broken off the strap so I  will need to effect a repair, for which I have a plan.

The photo below is of a very early 10H. Does anyone know what the centre distance is between the eccentric hole and the fork pivot. I can estimate this but would if possible like to repair to the original size. Note it is not the same as the current 10H

Cheers Geoff 

[JasonBModerator @jasonb]

There is a guy on MEM called Sanjay who is a prolific restorer of old engines. He did an early 10H a few months ago and I’m sure he will give you any info you need. He is away at the moment so may not reply for a few days.

If not a member you may need to register to see the images in his posts but probably not as he uses Whatsapp links for most rather than attachments. See this thread on the engine

[Nigel Graham 2Participant @nigelgraham2]

Oh dear! Someone in the past has made a mess of that eccentric strap and its studs!

It looks as they have bent those and strained the strap by forcing the nuts down onto curved surfaces that really needs little flats for the nuts to bear onto.

If the rod is not distorted, and assuming the division is perpendicular to the road axis, as they usually are, it’s possible to measure the centre distance quite easily.

Remove the rod from the engine. Stand it vertically by its flats on a surface-plate (or similar, such as milling-machine table) supported by an angle-plate, measure the height to the tangent top of the pin, then subtract the pin radius.

Alternatively, use a vernier to measure from the pin to the crown of the internal arc, subtract the pin radius, add the sheave radius.

[half whitParticipant @half-whit]

Thanks for the replies,

Jason, it looks like sanjay has the complete strap and arm. I’m guessing the size I’m looking for is around 2.5 to 2.625″

I only have the strap Nigel. The arm broke off. The photo is not my engine.

The sketch below is how I plan to add the arm

.

[JasonBModerator @jasonb]

If I had an engine with a broken or missing strap I would go about finding it’s length as follows.

Remove the valve chest cover so you can see the valve etc.

Rotate the valve rod to make sure there are several turns of thread available each side of the rectangular nut.

Position the valve so it is central to the ports

No measure the distance from ctr of the crank shaft to ctr of the hole in the valve rod clevis. This will be the size to make the strap/rod ctr distance.

 

[Blue HeelerParticipant @blueheeler]

Good luck getting this old girl running nicely again, looks like a lovely early one.

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