Cry for help with 5″ gauge manor class loco

[Carl BridsonParticipant @carlbridson37919]

my friend and I went half son a manor loco which we bought off of eBay. We paid quite a sum of money but desperatly need some help and wondered if anyone from this forum could point us in the right direction please. We ran it a couple of times and were told by the local club members in Cleveleys near Blackpool that the timing was out. This was due to various worn parts in the mechanism. We stripped some parts and replaced the bushings where required and now need to set the timing but have no idea where to start. Any help would be really appreciated so thank you in advance. Carl Bridson …………………….

[Carl BridsonParticipant @carlbridson37919]

[julian atkinsParticipant @julianatkins58923]

hi carl,

is your version the slide valve or piston valve version?

both use the same valve gear despite martin evans' misunderstanding the use of launch links with direct drive for slide valves (outside admission). the slide valve valve gear version is defective, as requires a considerable suspension offset where the bottom of the lifting links joins with the expansion link which isnt as per the drawings.

cheers,

julian

[Chris Lewis-CooperParticipant @chrislewis-cooper44097]

Hi People.

Sorry to revive this old post, but I too have acquired a Martin Evans 5" Manor (with piston valves).

Having carefully pored over both the plans and the ME articles, nowhere can I find the advance angles for the eccentrics (which are slipping). ME No 3469 details the method, but gives no data. It does say "shift the eccentrics around on the driving axle until they are in the position shown on the drawings as near as possible by eye". However, I can find no such drawing.

I could start at 90 deg and then just fiddle, but I'd prefer to get it right.

Can anyone help?

Chris

[julian atkinsParticipant @julianatkins58923]

Hi Chris,

You will not find the angles of advance for the eccentrics on the Torquay Manor drawings because Martin Evans did not know how to work this out.

With Stephensons valve gear there is an optimum setting of the eccentrics for best valve events.

You can these days work all this out accurately and quickly on a computer on a valve gear simulator such as Prof Bill Hall's. Or you work everything out mathematically using Don Ashton's book.

Or you can guess the angle of advance by laborious minor alterations at certain cut offs and noting the amount of lead at Front Dead Centre (FDC), and Back Dead Centre (BDC).

On a piston valve loco I would use the cylinder drain cocks to find out when the valve opens to steam, checking first that the drain cock holes are not obscured by the piston at the end of it's strokes.

The GWR Churchward Stephensons valve gear uses relatively short eccentric rods which causes lead to increase far more as the gear is notched up when compared with other arrangements.

Therefore your Manor should be set for the valves to provide negative lead in full gear cut off of say 79%. A good starting point would be negative lead of 10 thou in full gear. This will result in lead not being excessive when the gear is notched up.

Each time you alter one eccentric or both the valve will need centralising again to produce equal leads – which is rather time consuming on a piston valve loco.

FDC and BDC must be accurately established and not guessed at.

Cheers,

Julian

[Chris Lewis-CooperParticipant @chrislewis-cooper44097]

Thanks Julian – very useful indeed. I will now go and do some more focused research on the math I've already established FDC and BDC (I used the procedure in **LINK**).

I’ll calculate the positions of the eccentrics to set them before fine tuning and testing. The current grubscrews are easily accessible through the straps – God bless the original builder! Since the loco was a very smooth runner some years ago I'm going to start by assuming the valves will be properly centralised once the eccentrics are in the right place. There are two valve setting plugs on the valve cylinders so I can do a final check at the end.>>

Once the eccentrics are properly set I'm thinking of drilling the axle for the grubscrew, adding another locking grubscrew and loctiting the eccentric in place to stop them slipping again. Would you advise this?>>

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