1930 engine strip - flywheel

[Brucegirvan]

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[Brucegirvan]

Having the right kit makes it easier.

Wonderful!
As someone said some time ago, and I presume he was also a Lancastrian, - "Tha carn't do owt baht right tackle".
….
Don't forget to make a punch mark on the cam gear boss, relevant to the keyway, so that you can put it back in the original position. There's a 1/3 tooth difference.
There should also be a punch mark at 6 o'clock near the teeth of the camshaft gear when the punch mark at 12 o'clock on the crankshaft gear shows TDC.
They should be opposite each other, although as it's many years old, the engine might have been 'fettled' a few times since 1930 and there may be a few marks.

And, dare I say it, the right advice! I can’t thank you and the other pre-war technical supporters enough for being generous with you time and wisdom etc. Jowett.net records some great tips and thoughts - an invaluable resource of the now and future as so much sage knowhow is still on two feet, so to speak. But of course, part of the fun of Jowetting is meeting the faces and listening. I am always open to learning and would never turn down any advice or thought even if I think I may have heard it before because you just never know when it may come in useful. As for Jowett 7hps…it is all a new learning curve for me so I am all ears always. I just wish I could have our Jowett legends on hand in the grange as I delve away, just imagine the fun in that form of learning for me! Which is why Keith and Chris’s technical workshops are so well received down here in the South.

As for the timing, I am beginning to realise that these twins are sensitive to set up.

Thanks again, Tony

[Tony Fearn]

Perhaps it would be of use to post again within this subject one of my previous posts from 2007.
It also includes measurements for the flywheel puller which Keith suggested we could have made if someone could make the engineering drawings.
I don't know how to do this. My background is in Pathology.

Fly wheel removal.
Post by Tony Fearn » Fri May 11, 2007 12:21 pm

Alan.

Ian Priestly and I used the 'Braddock' technique George mentions to remove the much smaller crankshaft sprocket at the front of the engine of my 1927 Long two, and I was surprised that it worked. Shouldn't have been really because I.P. is a whizz at all things vintage and pre-war.

I haven't used the technique for flywheel removal though, only the 'puller method'. The large nut on the rear of the crankshaft is a 7/8 Whitworth size, the same size as the crankshaft sprocket retaining nut at the other end.

If I remember correctly, the 7/8" box or ring spanner won't fit over the clutch centering bearing on the back of the crankshaft. If it did, you would be able to prise it off whilst undoing the nut. If not then take care removing the bearing. It is a tight press fit on the shaft end, easily smashed and rather expensive to replace. (N.B. When rebuilding, make sure there are no burrs on the shaft end and offer the bearing to the shaft at 90 degrees before gently persuading it back into place using the inner ring of the ball race and a hollow drift.)

The flywheel itself can't be turned as Keith suggests because there is a keyway machined into the inside of the central boss which fits over a Woodruff key on the crankshaft end.

The starter ring will be heat-shrunk onto the flywheel rim, so if all else fails, it can be removed by an expert, turned though 180 and re-fitted.

Some pre-war fly wheels had 80 teeth and others 79 teeth I think, so if you are swapping one for the other make sure the tooth count matches or you might get the starter jamming in the future.

Another thing to watch for is that although most flywheels have the little arrow stamped on the rim to show Top Dead Centre (TDC), we have come across the odd one that when the arrow is visible at the top, the pistons are actually at Bottom Dead Centre (BDC)!

Back to the puller: - As well as the 6 clutch spring recesses on the inside of the flywheel, there are a couple of smaller holes drilled right through, one at either side of the central boss. These are drilled to take 1/2" Whitworth threads. To make a puller you will need a piece of 3/4" steel plate 6" x 3" and drill two holes 3 1/2" apart at their centres. The pair of holes should equidistant from the short ends, and on the centre line of the long axis. They need to be about 9/16 ths each.

Two 3 1/2" long pieces of 1/2" Whitworth screwed bar and nuts are also needed.

After removing the flywheel nut and washer, screw the screwed-bars into the 1/2" draw holes so that they just show through on the back side. Put the heavy iron plate over the bars and allow to rest on the crankshaft end. Put the nuts on and tighten up each side a bit at a time. If you are lucky the flywheel might come off. If not, and making sure that there is a fair bit of tension on the puller, clout the centre of the puller with a lump hammer. If it doesn't come off at this stage, perhaps you'll be able to turn the nuts a bit more and clout it again. Heat from a blowlamp onto the central boss might also help as a last resort, but do this outside with a bucket of water or fire extinguisher handy.

When the flywheel finally comes off so will the puller with it, and together they will be very heavy so watch your toes.
Tony.

[Keith Clements]

I think your description is adequate to make the puller. As far as I can see the only important dimension is the distance between the holes in the plate.