Misc: Everything Else 1951 Black Shadow Restoration

greg brillus

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If the hold down studs are original steel ones, then buff them over especially the threads themselves, then lay them out and paint them end for end with some silver engine enamel spray........If stainless then just visually check the threads for any sharp burs/edges, perhaps lightly buff the threads anyway........no paint necessary.......Lock 2 of the 1/2" BSF thin nuts 879 together on each stud........coat only the upper threaded section of the lower thread with your choice of sealant..........wind each stud into the holes and tighten with a ring spanner 13/16" will work fine, with length not more than 300 mm, with normal hand strength up nice and tight.........no torque wrench needed..........swap the nuts to the next stud and repeat over. Wipe away the excess sealant at the base of each thread. Do you have all the bearings, oil pump sleeve, and spindles in the cases at this stage...........?..........You should fit the output shaft seal, the shaft itself with the 3 rd gear and spacers, sprocket, seal cup and nut before installing the G 50 plate.........Make sure the bushes in the output shaft are in good order with some running clearance.........new bushes tend to shrink a bit when they are installed thus need to be reamed out to suit the input shaft sizes..........The shaft should spin freely with the slightest of play felt.........never run them tight, as they will quickly destroy themselves, especially the large inner one the G 16.
 

craig

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Do you have all the bearings, oil pump sleeve, and spindles in the cases at this stage...........?..........You should fit the output shaft seal, the shaft itself with the 3 rd gear and spacers, sprocket, seal cup and nut before installing the G 50 plate.........Make sure the bushes in the output shaft are in good order with some running clearance.........new bushes tend to shrink a bit when they are installed thus need to be reamed out to suit the input shaft sizes..........The shaft should spin freely with the slightest of play felt.........never run them tight, as they will quickly destroy themselves, especially the large inner one the G 16.
All crank case bearings, spindles, oil pump sleeve are in and ready to go.
G4 (and G3) is new and a nice slide fit into new bearing.

It appears G50 should be in place without any additional gearbox pieces.
It G50 would appear to be of benefit when tightening the crank case bolts A thru M.
Yet for some reason I cant find G50 mentioned, as part of the crankcase boltup, in any of my references.


MO41.jpg
 

stu spalding

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Hi Craig, I'm not sure why you need to fit G50 before assembling the cases. It helps if studs A,F,M are removed and fitted after assembly. M is fitted with a nut and locknut but A and F don't have enough thread so long nut G72 is used with a bolt to lock it. Cheers, Stu.
 

vibrac

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G50 is essentially a removable component I had to take it off for the 22 T sprocket I am not sure if you need to for the 21T latterly a new G50 is needed for the electric start from France.
 

craig

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There are 7 bolts/studs that use G50 as a final clamping force to join the case halves.

Where is the bodge work around to clamp case halves freshly slathered
with anaerobic sealant ?......and documented work around?

You cant fit sprockets with a G50 in place?

A,F, & M need to be left out of clamping as well? Maybe to ease cylinder install?
So how exactly does an anaerobic sealant work?


MO41G50Question2.jpg
 
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Cyborg

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Nothing wrong with bolting the cases together, with all the studs. Once the sealant has cured, I can’t see any problem with installing the G50 after the fact. If the cases separate and break the seal once you remove those 7 nuts, then there is something drastically wrong. Assuming you checked the mating surfaces prior to assembling. Without a surface plate, it helps to put a bright light inside the empty cases in a dark shop. The results can be frightening sometimes.....speaking of bodges.
 
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craig

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I reread the "The Instruction Sheets" and it appears to me to indicate that G50 Pivot Bearing Plate is installed prior to case half assembly.

What would be the benefit of not having the G50 plate installed?
 
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Cyborg

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I read that as simply instructions on how to reinstall the G50 if it was removed. The reinstallation instructions for the G50 weren’t in the original instruction sheets as far as I know. Someone added that at a later date. In any event, the G50 doesn’t have to be installed before assembling the cases. If you wish to, go ahead, but installing it afterwards is definitely not what I would consider a bodge. Same as if you replace the G50 at some point because of damage or the need to pull the oil pump. The cases don’t get split. If cases aren’t warped or mating surfaces damaged in some way, I don’t see it as a concern..... and if there is damage, chances are it’s going to leak regardless...
 

greg brillus

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You are better off installing it first, just as you should install the front engine/prop stand assembly as well, perhaps less the 2 stands themselves.......The main advantage is that you can fully assemble and tighten all the case studs and then hopefully not disturb them again. Loosening one stud afterward is ok, but to have to loosen several to have to fit a major component is very risky.........again pending what sealant you use on the main case joint.........In any case there will be oil present especially that run off the crank assembly, and the loosening of several studs could easily result in a near permanent leak at the main joint. Remember if you back off all the studs that secure the G 50 plate and hence the gearbox housing itself..........all the lower studs that pass into the primary housing could shift or come temporarily loose.........these will then almost certainly leak oil along their length .........sealant needs to be installed under the heads of these through studs, just as some of the forward ones within and at the very top of the timing chest as well. These studs can cause mysterious leaks that seam impossible to fix, so again these studs should ideally not be disturbed afterward..........It is all doable, it just takes some careful preparation, and check all the stud lengths, and trim them if necessary........I hate the look of too many threads hanging past the nut, even if washers are used........this is most obvious on the lower front engine plates, and the studs bellow the front cylinder.
 

craig

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Made progress today. Many thanks for the tips on this assembly.
All the studs and bolts went as needed except for one "G" bolt .
I will pull that one G bolt and file the head down.

What a heavy lump this is now,


20210411_EngineProgress1.jpg
 
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