Timing Case Assembly

Martyn Goodwin

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About to start - well in a week or so - on the reassembly of my comets timing case, that was in part stripped by another.

When assembling the crank cases there is drawing M065 to guide one - it shows the position of every crankcase stud and also, in cross section shows exactly how each stud is assembled. where washers go, wher shims go etc.

When it comes to assembling the timing case there is no such clear guide - at least not that I can find. M013 that shows the timimg group comes close but I suspect that there are still things left to the imagination.

Anyone know of a guide that provides the assembly sequence , spindle by spindle, for the components on each spindle within the case? It could even simply be a list for each spindle - this goes first, then this , then this and so on including the steady plate and the final washers and nuts.

Martyn
 

BigEd

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VOC Forum Moderator
In Richardson:
Chapter: Fuel System, Timing Gear and Exhaust System, Section:Camshafts. (Page 113 in my 1960 edition, your page number may differ.) He says where the thrust washers should go and the end float specification.

N.B. In Know Thy Beast: Chapter: Timing Chest, Section: The Steady Plate, Nuts and Washers. Stevens says there are minor misprints in Richardson, Vincent Motorcycles and the Illustrated Spares List. He states: "It should read: one thrust washer 3/8" ... inside. In the Series C and D lists, the 5/16" washer outside the breather pinion is omitted from drawing M013 .......... On some Comet engines there is enough end-float to fit a thin 5/8" washer ET173/1 inside the small idler in addition to the standard thick washer ET173 fitted on the outside."

There are two pdf files in the forum download section that list some possible ommissions and innacuracies in the parts drawings that may be of use.
 

Howard

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When you follow the instructions, don't be surprised if all the washers don't fit on some spindles, and other spindles need extra washers.

H
 

chankly bore

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Yes, the Workshop Instructions are a counsel of perfection regarding the original Datum face (timing cover mating face) and heights of spindles relative thereto. 60 years of wear and warp and oddly manufactured components supplied in that time all lead to this: Start with a good round cam pinion with the cam of your choice, running on good bushes, Get the followers tracking central with whatever shims they need, get a good steel idler on a one-piece boss and prove as near as dammit zero backlash, then ask your friendly spares man for a selection of half-time pinions and get the same backlash after checking for tight spots.Fit a steel small idler. Set the generator pinion with a little free play if you must- it is better than stretching your seals there. prove your oil feed to the camshaft and the back of the piston. Laurie Binns has a jig to insert spindles to the correct height. Your spares man has many shims in stock. By the way, I went to .005" bottom skirt clearance with a noisy exhaust like yours you should do likewise!
 

clevtrev

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I`ve mentioned it before, when building a Comet chest, the first thing in place is the dynamo pinion, just to make sure you get it in the middle of the seal.
 

Chris Launders

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You should go for a steel idler, I found my alloy one was egg shaped when I tried setting the backlash to quieten my rattling comet timing side.
Chris.
 

redbloke1956

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Non-VOC Member
Yes, the Workshop Instructions are a counsel of perfection regarding the original Datum face (timing cover mating face) and heights of spindles relative thereto. 60 years of wear and warp and oddly manufactured components supplied in that time all lead to this: Start with a good round cam pinion with the cam of your choice, running on good bushes, Get the followers tracking central with whatever shims they need, get a good steel idler on a one-piece boss and prove as near as dammit zero backlash, then ask your friendly spares man for a selection of half-time pinions and get the same backlash after checking for tight spots.Fit a steel small idler. Set the generator pinion with a little free play if you must- it is better than stretching your seals there. prove your oil feed to the camshaft and the back of the piston. Laurie Binns has a jig to insert spindles to the correct height. Your spares man has many shims in stock. By the way, I went to .005" bottom skirt clearance with a noisy exhaust like yours you should do likewise!



In the words of the great Julias Somner Miller "Why is it so?" 5 thou sounds like a lot of clearance to me??
...........Livin and Learnin...........
 

chankly bore

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Non-VOC Member
I nipped up twice on a brand new Specialloid at .004" bottom skirt, reasons, (I think) modern shite fuel and fairly de-resticted pipe. Since going to .005" no greater noise, no increase in oil consumption and no more "usual noises louder than usual". My other Comet runs .003" Kempalloid, sealed valve guides and uses no oil! As Big Sid would say; Go Figger!"
 

Bill Thomas

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The old Specialloid for racing is I think 9.5 thou, I use 10 on my road bikes, If you live in a hot place and ride hard !! How hot is it in AUS, Never been there, Cheers Bill.
 
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