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Topics - sinna42

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Original Lister Cs Engines / Lister CS Fuel Tappet alignment
« on: May 12, 2020, 05:28:46 PM »
This is a bit of an odd one !
During the strip down of my 1952 Lister CS 12/2 I discovered that the bores in the Camshaft Covers for the Fuel Tappets were very badly worn.
Along with this there was wear on the camshaft ends as well.

So to do the job properly the camshaft ends have been skimmed to first clean cut & new undersize bronze bushes made to suit.
For the bores for the Fuel Tappets I'd get a new cast iron bushes made with the correct bore, which is 1" reamed.

Now while boring out for these new cast iron bushes this is where the oddity has been discovered.
See photo attached that shows the setup on a milling machine.
Initially the mounting face & bore for the fuel pump was set up true & square. I thought this would be the true datum & would be in accurate alignment with the camshaft centre line, but no, it isn't !
The governor end camshaft cover was out by a good 0.030" & the other end out by 0.010".
I couldn't think how that could have occurred, but perhaps this alignment didn't actually matter ?
I decided to minimise this error so the new bore will be much better aligned to the camshaft centre line & still be perpendicular to the mounting face for the fuel pump.
See second photo that shows a witness cut where you can see the offset to the original bore.
In practical terms this now means the fuel tappets are not acting on the centre of the fuel pump.

I suppose this is not something that has been observed before but it'd be interesting to hear any comments.

Cheers,
Jim

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