Author Topic: rocker box gaskets again  (Read 4090 times)

Offline Stephen Foster

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Re: rocker box gaskets again
« Reply #15 on: 06.11. 2013 07:57 »
I had realised that some rocker box faces seem narrow but was considering putting extra material in the narrow areas by aluminium welding (T.I.G) , dressing
back then cutting a suitable groove ..not sure which tool would work here ?

Wondering if a Dremel type affair with suitable bit might work ?

Interested in any input as Id been mulling over this for a few years as this is the main oil leak om My "Flash" .

Steve ...
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I own a 1955/56 B.S.A Swinging Arm "Golden Flash" , had it since 1976 .

Offline muskrat

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Re: rocker box gaskets again
« Reply #16 on: 06.11. 2013 09:52 »
G'day Stephen. The ones that look narrow in places are probably the SR type. The casting # is overstamped with 1142.
Cheers
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Offline duTch

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Re: rocker box gaskets again
« Reply #17 on: 07.11. 2013 10:23 »

 When I made mine, from paper(~.4mm?), I allowed for the mis-matched facing thickness, and made them over big inside and out with a view to trimming them back (some time)after tightening down and a bit of use- looked a bit funny, but doesn't leak (much)- maybe only if I look at it..?
 Also used 3 Bond both sides,and silicon grease head side so R.box comes off easy, and have removed it a couple of times and literally thrown it back on with just a wipe of mating surface. I'm happy.
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Offline muskrat

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Re: rocker box gaskets again
« Reply #18 on: 07.11. 2013 11:22 »
I still think the head steady on the s/a models contribute a lot to the r/b leaks. The earlier ones don't seem to leak as badly with the steady mounted under the front r/b studs.
Cheers
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Offline Stephen Foster

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Re: rocker box gaskets again
« Reply #19 on: 07.11. 2013 11:53 »
"Muskrat" ,
Assuming the cast head / rocker box faces on My "Flash" are reasonably meaty (they are) what tool would You
reccomend I try for cutting a groove ?

Steve ..
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Offline muskrat

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Re: rocker box gaskets again
« Reply #20 on: 07.11. 2013 19:12 »
G'day Steve.
If I were to try it (don't think I will) I'd start with a 1/32" circular burr or diamond encrusted Dremel bit, then go to a 1/16". I'd also mark out the shape on a sheet of alloy and practice at least 50 times, no beer or sex for three days prior. *cry*. There is a formula for the size of the groove for the size of the O ring, can't remember right now. Find an old stuffed r/b to try on before the good one.
If money was no object a CNC mill and a map programed in would be great, then you could do all of ours. You'd need to do 1000 units @ $50 to cover the mill and set up. *eek*
Cheers
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Offline shuswapkev

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Re: rocker box gaskets again
« Reply #21 on: 17.11. 2013 20:44 »

  my 1951 G.F. was built completely out of stray parts and leftovers...so..i did every " flat "with sandpaper and a thick glass plate

all the rocker boxes i had were quite lumpy..esp in the areas of where the bolts came thru....the head surface??  dunno as I had the head guy surface both sides... I would find it hard to believe that after 60 some years it would still be flat..
the gasket thing??  once i stopped using paper gaskets.. I stopped having problems with oil leaks.....Loctite 515 517 or?? I cant see any difference...seems to work the same...
only problem with curing all oil leaks...is chasing the rust... I live about 15 minutes from a surf beach....but I have worked out how to stop the rust...I have a spray bottle with light oil...and a regular spray seem to do the trick...and makes it smell like a BSA...

if you haven't surfaced the mating parts...might be in for a surprise... after a few strokes...start wondering how in the world did that thing even hold oil..."?? some of mine were only hitting on three corners
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Offline Rocket Racer

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Re: rocker box gaskets again
« Reply #22 on: 18.11. 2013 02:57 »
I still think the head steady on the s/a models contribute a lot to the r/b leaks. The earlier ones don't seem to leak as badly with the steady mounted under the front r/b studs.
Cheers

I agree with that view,  having the rocker box anchored to the frame is problematic for any engine that works hard.  *sad2*
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Offline kiwipom

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Re: rocker box gaskets again
« Reply #23 on: 18.11. 2013 21:29 »
Hi guys, the head steady is the obvious problem so what would be the effect if it was not used,cheers
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Re: rocker box gaskets again
« Reply #24 on: 18.11. 2013 22:22 »
Shake, rattle and roll!

A lot more vibration without the head steady.
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Offline Rocket Racer

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Re: rocker box gaskets again
« Reply #25 on: 18.11. 2013 22:27 »
potentially the front engine to frame brackets would fail (break  *sad2* )
Head steadies are useful things, just a matter of attaching them to something that is suitably solid on the head, rather than the rocker box.
Norton heads have a solid casting to mount to, but are even worse to assemble pushrod wise.
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A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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Online groily

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Re: rocker box gaskets again
« Reply #26 on: 19.11. 2013 17:43 »
"Norton heads have a solid casting to mount to, but are even worse to assemble pushrod wise"

Ain't that the truth RR. First time I had to take the top off the Atlas engine in my P11, I swore I'd rather do 100 Beesas, in the dark. In fact, on those sorts of hybrids, it's a close call whether to take the engine out to get the head off, it's all so tight.

As for head steadies and rocker boxes  . . . the "just a matter of etc" can be a poser, on most marques. But have to say, on my A, only a little oil mist around the edges on the rare occasions I actually get around to cleaning it. Not enough to stop the cast iron bits from going rusty. As Manormike knows, who started this discussion, mine is a million miles from being a vision of loveliness. But despite the odd glitch she has worked, does work and I hope will keep working, with less time spent on keeping it that way than on pretty much any other old bike I have ever had. (Except a B31 - but of course.)

Having had the opportunity thrust upon me recently to rebuild the oily bits of a quite pretty sprung-hub Triumph, I know which I prefer. And it doesn't begin with T.

Cheers

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Offline Rocket Racer

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Re: rocker box gaskets again
« Reply #27 on: 24.11. 2013 19:14 »
Finally had a look at removing my race engine after its last 3 day race meeting, broken head steady and damage to the cases at the top rear engine mount  *sad2*
Yes these engines need all the support they can if being given a hard work out.
So it'll need repairs to the crankcases before it goes out again as well as reviewing/replacing the head steady.
The good news is there was no evidence the rocker boxes weeped  *eek*
 
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Offline Briz

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Re: rocker box gaskets again
« Reply #28 on: 24.11. 2013 20:08 »
Yeah; dont delete the head steady! Bad idea.
Think of it this way, that engine is thumping away making - what?- 50 ft-lbs torque? So whilst applying that torque its trying to turn itself in the opposite direction to the engine sprocket.
That top mount helps contain that torque. All the other mounts are much closer to the crank, so theres more force acting on them. Leave the top one off & all the others will come loose a lot faster.

Offline muskrat

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Re: rocker box gaskets again
« Reply #29 on: 25.11. 2013 12:28 »
I replaced the std bracket with two pieces of steel tube squashed at both ends (at 90 deg) and drilled. Just using the rear bolts. No probs for the last 5 years.
Cheers
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