Author Topic: 2 3/4 Barrels with cast valve guides  (Read 259 times)

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Offline GlenDouglas

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2 3/4 Barrels with cast valve guides
« on: 21 Jul 2018 at 20:22 »
On my 1915 2 3/4, looking at fixing the valve guides.

My challenge looks like they are machined from the original castings.

Any ideas ?

Offline Jonathan Hewitt

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Re: 2 3/4 Barrels with cast valve guides
« Reply #1 on: 22 Jul 2018 at 20:21 »
with various cylinder heads I have had my local machine shop put in inserts / liners if you like into the original guides. all be it that the heads I had done were for our small marine engines but the process is the same. Just a thought before boring out big chunks. I believe that they put in a sleeve, expand it with a ball bearing and then finish size with a reamer.

Offline Andy Smith

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Re: 2 3/4 Barrels with cast valve guides
« Reply #2 on: 24 Jul 2018 at 22:36 »
Hi Glenn
I think a good looking at is required, consider how the pattens were lifted out of the mould they are unlikley to be cast in, I suspect with care they will drift out from the valve head end might help to warm it up although its all cast iron but definitely for when you put the new ones in.

Offline Chris

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Re: 2 3/4 Barrels with cast valve guides
« Reply #3 on: 25 Jul 2018 at 05:32 »
The early cylinder barrels for 2.3/4hp did indeed have cast in valve guides. various tools have been made over the years to enable worn cast in guides to be machined out to leave a bore of the correct size to fit the later press in valve guides for both inlet and exhaust. Replacement guides are normally held in stock and available to members only from the LDMCC Spares Scheme.