Series "A" drive side ball bearing and engine build.

greg brillus

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VOC Member
Thanks Peter, getting back to the bearing housing set up, I think changing the design from the semi floating pre war verses the solid on the post war was definitely an improvement if nothing but to save wear in the steel housing, but it all means little now as they all seem to have survived this far without complete destruction. It is interesting to see the difference though. I could not compare this to the new replica twin engine I built last year on account of it running the back to back taper rollers on the drive side..........Pretty good mod at that. As for the alloy washers, I think these are aircraft parts, as I seem to remember them from years ago when we restored a couple of British planes. I think a small smear of ThreeBond on the cam box will minamise oil leaks I hope. Today I assembled the bottom end after changing the two timing side bearings, the front and rear engine plates with original finish "Black" studs and cad plated nuts and washers. I should get my act together so I can post some pics on here for you. It is coming together really nicely. Cheers.............Greg.
 

Simon Dinsdale

VOC Machine Registrar
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VOC Forum Moderator
Greg,

My take on this relates to the expansion and contraction of the cases in an axial direction. Yes the timing side shaft is fixed, but there will need to be some give at the d/s outer main bearing to account for the expansion/contraction movement. It will try to press itself against the "tin-hat cover". If the sprocket boss, once tight, can arrest this movement to prevent the bearing pressing against the tin hat then that would be advantageous. After all, Phil put the spring there for a reason, a solid spacer might be a recipe for disaster. :eek:
Peter B
Its a few years ago, but I seem to remember when my Dad and I assembled my series A Comet, with all the bearings, shims, chip guards etc in place, the outer driveside ball bearing was pushed tight up against the outer bearing cap (tin hat). When the sprocket was tightened up you could feel it pushing against the spring between the bearings so the spring is there to allow the crank to float in this area, but also to keep pressure on the outer chip guard & washer/spacers so they all rotate and move as one and have no independent play. Bob Stafford once said that if there is too much clearance in the chip guard/shim/spacer area on the outer bearing then the primary chaincase will slowly fill up with engine oil. A sealed bearing would help with that.

Simon
 

Bill Thomas

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Yes, Greg, exactly as you said - but without loctite. It does need to be able to move a tad (precision engineering term) under the influence of the Thackeray washer.

I don't wish to hi-jack your question, but, while we are on the subject, does anyone know of a source of that Thackeray washer?

Peter B
Hello Peter, Long time since I have seen inside an "A", But is the washer you are talking about, Just a big flat spring washer, I have found a few odd bits over the years from when Ron left home I gave him some handle bar bits last year.
I have found a strange washer, Just under 27mm I.D. Just under 43mm O.D. Just under 2.5mm thick.
It's a long shot but I don't want any "A" bits put in the bin !. Cheers Bill.
 

Robert Watson

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Both my A's are converted to post war style setups on the Drive side. Obviously a new housing is required as is a new main shaft and a new sprocket. It really did simplify life in that area. On the TS the ball bearing was replaced with a roller.
 

VinMog

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Non-VOC Member
The cam
20180305_164532_resized.jpg
20180305_164556_resized.jpg
boxes on my twin and single both have alloy washers. Good Luck with the rebuild John C.
 

greg brillus

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Hard to know what exactly is original.............Ok next question........Does anyone have any specs for the black paint used on the cast Iron cylinder head and barrel. On the post war Shadows we paint them in two pac eurothane but perhaps a heat type paint would be better on the Iron parts due to the heat they generate. I'm thinking perhaps a satin black finish rather than gloss or flat. Cheers...............Greg.
 

timetraveller

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VOC Member
Greg, over here the paint is easy to obtain. It is generally listed under 'exhaust manifold paint' and is generally used by car restorers who want to have their under bonnet car bits looking as smart as the outer body bits. It is available under a wide range of colours and can be gloss or mat finish. Some of it is listed as coming from China so it probably is available in Oz. If not then I could probably send some. I have never used any so cannot vouch for the quality but straight onto the exhaust manifolds as they come out of the cylinder heads must be a fairly severe test.
 

Dinny

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VOC Member
Looking at the factory pictures I would say they should be flat or satin finish as none look gloss to me. Probably flat. Thats what I'm going to do as gloss does not look right.

Mark
 
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