Felt rockerbox seals

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
Steve64
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Felt rockerbox seals

Post by Steve64 »

Hi everyone, I have just received a few spare parts for my 46 500 Matchless and I am having a great deal of trouble getting the felt seals into to rocker box, they seem way too big . Is there a particular way to do this or is it just a mongrel of a job. Was there only one size of these seals available , maybe I have the wrong ones. The part number on the AMOC list was the same as the parts book but the outside diameter is far greater.
Any advise would be greatly appreciated.
Thanks , Steve
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ajscomboman
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Re: Felt rockerbox seals

Post by ajscomboman »

They are correct and yes it's a bugger of a job. Just done a rebuild on a rocker box and had the same issues but got there eventually.
Greybeard
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Re: Felt rockerbox seals

Post by Greybeard »

Ive found that the best way is to soak them in oil first then use a rounded bullet nosed mandrel to force them into position. I made a brass end that fits into the rocker tube - it looks like a large calibre bullet. It often pushes a small amount of surplus felt out but it does work. The brass bullet has to be short enough to come out through the space at the inner end. Does that make sense? I can post a picture later on if needed.

Steve
Steve64
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Re: Felt rockerbox seals

Post by Steve64 »

Thanks guys for the quick reply, it sounds like it will take a bit of persistence but at least I know that I should eventually get there. Greybeard, great idea by the way , will give that a go.
Cheers guys 👍
Andy51
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Re: Felt rockerbox seals

Post by Andy51 »

When I rebuilt my '54 18S I struggled for ages to get the felts in, then I read a Classic Mechanics article (available in Christian's Archive) by no less an authority than Ken de Groom, who said he doesn't bother with the felt rings as they serve little or no purpose. I took this advice, ditched the seals and 15 years later all is still well with the motor! So, save yourself a lot of trouble and chuck them away. Andy
uas526
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Re: Felt rockerbox seals

Post by uas526 »

Ha, I also have that article, and also lack the seals. So much oil up there in the rocker box, I can't see how it would make any difference.
SPRIDDLER
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Re: Felt rockerbox seals

Post by SPRIDDLER »

Andy51 wrote:When I rebuilt my '54 18S I struggled for ages to get the felts in, then I read a Classic Mechanics article (available in Christian's Archive) by no less an authority than Ken de Groom, who said he doesn't bother with the felt rings as they serve little or no purpose. I took this advice, ditched the seals and 15 years later all is still well with the motor! So, save yourself a lot of trouble and chuck them away. Andy
That's exactly what I did at about the same time as you on my '54 G3LS.
'There is a tide in the affairs of men
Which taken at the flood............'
Steve64
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Re: Felt rockerbox seals

Post by Steve64 »

Sorry for late reply, thank you for all of the advice. I will persist for a bit longer before I lose patience and throw them away.
Cheers guys, Steve
Stuart Jenkins
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Re: Felt rockerbox seals

Post by Stuart Jenkins »

Hi Steve,
This is a good video by Dick Casey on all this 'rockerbox'



Stuart
g3l 1941
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REW
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Re: Felt rockerbox seals

Post by REW »

I did the felt insertion job (ooer) some time ago and this is how I described it then:

There is a thread on this in the G80 section but this applies to all heavyweights and maybe other models, so here it is.

Whether useful or not these felts are a pain to fit, so I made some to be a sliding fit on the axle using a 6cm by 1cm strip butted and sown into a hoop. I used oil filter felt spare from re-sowing the poorly fitting pattern filters we tend to receive from parts sources (I did an item on this once). Any way, start with this:

Sow the strip edges:

photo missing, sorry

Et voila:

missing again - these where on the older forum

Folded into a U shape and they pop in between the two rocker bushes. Press down the further edge with a pencil or drill shank. The rocker axle should be rotated as it is inserted and may need to be twisted for a while to get past the stray felt at the start of the second bush - but don't force it. I did this without oil and once in place spun it a few times and reciprocated it and it slides nicely. No idea if it is any good, but I feel better for trying it.
Ron

1951 Matchless G3L thumping round the Durham Dales.
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