The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Swarfcut on 21.04. 2024 10:24
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Making gaskets.....
Back in the day, and even now, I have no hesitation to make a gasket from whatever is to hand, Cereal packet card is good, as is 6 pack card. My dad showed me how to tap the card against the sharp edge of the casting, producing a perfect cut and a good copy of the genuine article. I was gobsmacked by this make do and mend philosophy, how simple and convenient it was, and used stuff to hand. That was a long time ago.
These days I don't attempt to cut out bolt holes with a drill or blade, but instead tap the dome head of a coach bolt into the card over the hole. Put the bolt in the hole to keep the card in place and tap round the casting with the narrow end of a carpenter's hammer and see your Corn Flake gasket emerge in all its glory.
The cost of a full set of gaskets these days is poor value, so for the odd gasket make your own. Hylomar is still my jointing of choice, but bathroom silicone used sparingly is also OK in the right place.
I doubt whether many folks make their own now, so another skill to be lost.
Swarfy.
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Me too *smile*.
https://www.a7a10.net/forum/index.php?topic=12378.msg97110#msg97110
Reply #28.
Rog.
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G'day Swarfy.
I always make my own gaskets and do the same tapping around the edge. I get rolls of 0.4 and 0.8mm oil jointing but have used "corn flake packets". In over 40 years I've only bought 2 or 3 gasket kits. I use them as templates. As for goo I use Permatex #3 and a lot of the time the gasket is re-usable. Wad punches and sharp hobby knife works well.
Cheers
Roger got in first and that link shows my post almost word for word.
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I make all my gaskets by myself but with klingerseal gasketpaper in 0,3mm thickness. Yes its the same manner to "cut" this gaskets but I use a little brasshammer to save the surfaces.
Than I make copys from this gaskets as much on a sheet of paper. This gaskets can cut out on the outside with a scissor. Than I stick this on the gasketpaper cut out and a punsh for the holes. If the gascet is ready I smear both a little sides with HT silicone and let this dry.
These are the best gaskets I ever had in hand.
cheers Klaus
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Funnily enough, on Berg's suggestion, I was looking at nitrile sheet and nitrile bonded cork sheet to make a primary cover gasket. I was also looking at a cheap set of hole cutters (can get a small set for about £6).
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worty you can use a small one down the screw holes and punch out all the holes while the cover is on whatever stuff you use , that's what i did with the cork one.
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worty you can use a small one down the screw holes and punch out all the holes while the cover is on whatever stuff you use , that's what i did with the cork one.
Just as a quick aside Bergs, do you know where I can find info on which screws go where on the p/s cover. I know the three big, long 'uns go at the front, but I've sort of guessed at the rest. I think some may be the wrong sizes anyway.
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Worty, I'm not Berger (don't do gulpers enough) *smile*.
Here's my reference picture, Primary and timing covers. I put it on here a some time ago, but to save you looking - hope it helps.
(Edit): Sorry, first picture (colour one) attached was put on here by Col. I've included it - I'm sure Col won't mind.
Rog.
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Worty, I'm not Berger (don't do gulpers enough) *smile*.
Here's my reference picture, Primary and timing covers. I put it on here a some time ago, but to save you looking - hope it helps.
(Edit): Sorry, first picture (colour one) attached was put on here by Col. I've included it - I'm sure Col won't mind.
Rog.
Cheers Rog, really helpful. Any idea how many lengths of screw there are? Some sellers seem to list two, others 3. Just wanted to make sure I have the right lengths of screw in the right place next time the cover comes off.
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Here's another *smile*. 3 lengths, but different threads for the front 3.
(spending time on here, warm and sunny here in Plymouth for the past 3 or 4 days - normally would be getting some rides in *sad2*).
Rog.
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Brilliant, cheers Rog. Any idea why there are two part numbers for the same screws - am I missing something (67-1706 and 67-1711). On the timing side, apart from the short screws around the dynamo, all the others are the same length??
I'm going to have a look at this more closely when the covers come off for anything.
As for the weather, it's sunny but a bit chilly up near Leeds, you're nearer the sun than us!
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I make all my gaskets by myself but with klingerseal gasketpaper in 0,3mm thickness. Yes its the same manner to "cut" this gaskets but I use a little brasshammer to save the surfaces.
Than I make copys from this gaskets as much on a sheet of paper. This gaskets can cut out on the outside with a scissor. Than I stick this on the gasketpaper cut out and a punsh for the holes. If the gascet is ready I smear both a little sides with HT silicone and let this dry.
These are the best gaskets I ever had in hand.
cheers Klaus
Yeah gasket paper is best, but some office document folders are made from tough cartridge paper that makes better gaskets than cornflake packets.
(https://interculturaltalk.com/wp-content/uploads/manila-file-folder-label-241x300.jpg)
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Worty, I'm not 100% sure why, but I think probably one of the part numbers is for some shorter screws for a fully enclosed chaincase as they may bottom out against the chaincase, whereas with just the short chaincase they could be longer. *dunno2*
The screws are the same, but from the factory 67 1711 is listed as fixing/oil level and drain, so is the mythical Red Painted Unicorn Variant part. Plain type with the ready rust finish is 67 1706. *smile* *lol* *lol* *smile* Sorry Swarfy, just a joke *respect*.
Have a look here, primary screws discussed here: reply #45 through to 52.
https://www.a7a10.net/forum/index.php?topic=13099.45
As for timing side here's a picture of the drawing under the primary case on the .pdf I'd attached. 4 longer around the oil pump.
Rog.
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To answer Worty, the screws are the same, but from the factory 67 1711 is listed as fixing/oil level and drain, so is the mythical Red Painted Unicorn Variant part. Plain type with the ready rust finish is 67 1706.
Nut and bolt chart in the literature section of the forum gives a cross reference for part numbers to thread type in the majority of cases. Sod's law applies sometimes, the one you want is not listed.
Most important that all threads into blind holes are cleared out of muck, debris, old jointing, oil. If not screws may bottom before clamping force is achieved, or worse the hydraulic pressure cracks a weak casting.
Swarfy.
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My invaluable tool for cutting inside curves and holes, if using the flat or peening end of a hammer is not possible, or convenient. Obviously, I haven’t sprung for a hole-punch set.
Richard L.
Worked on the bike yesterday, so wearing the oily thumbnail with pride.
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To answer Worty, the screws are the same, but from the factory 67 1711 is listed as fixing/oil level and drain, so is the mythical Red Painted Unicorn Variant part. Plain type with the ready rust finish is 67 1706.
Nut and bolt chart in the literature section of the forum gives a cross reference for part numbers to thread type in the majority of cases. Sod's law applies sometimes, the one you want is not listed.
Most important that all threads into blind holes are cleared out of muck, debris, old jointing, oil. If not screws may bottom before clamping force is achieved, or worse the hydraulic pressure cracks a weak casting.
Swarfy.
Perfect🤣🤣🤣🤣🤣🤣
A thousand thanks Rog, extremely useful!!
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richard , shame on you ! TUT TUT those scissors are bent for nails and you have let yourself down you black finger nail person . the ones i have came from good old sheffield made by william rodgers , i think they were my grand dads so they are now old old.
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I have a wad punch set for making the gasket holes, but prior to that I used the trick my old dad showed me, namely a nut placed underneath the gasket material under the hole marking and a next-size-up bolt on top. Even better if you slightly round off the bolt end first to get a nice even cut.
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If you have a Model shop near you (thin on the ground nowadays) they'll usually have thin-walled 'K & S' brass tubing, -easily sharpened to make excellent hole cutters.
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We used to get our eng military billets almost solely based on if we could sharpen a 1/32 drill bit. As young fellas if we couldn’t support maintaining the tradesmens tools / work support etc (which included endless gaskets) - then no one wanted you….still get made fun of for only using pencils at work & for polishing my boots every single night 🤣
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I use a leather punch to make the holes then cut the gasket. I've learned the hard way not to leave the holes to last!
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G'day Rob.
Yes holes first then inner and outer last.
Cheers
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G'day Rob.
Yes holes first then inner and outer last.
Cheers
I can see that.
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richard , shame on you ! TUT TUT those scissors are bent for nails and you have let yourself down you black finger nail person . the ones i have came from good old sheffield made by william rodgers , i think they were my grand dads so they are now old old.
Bergs,
Hey, I wouldn’t argue that scissors are better for holes than punches, but if one (like me) has to use scissors, the small nail clipper does a decent job for small holes. Your classic (scissors, that is) looks much larger.
Regarding black finger nails, it’s the norm, just not when I’m working as a high-fashion hand model. *whistle* *beer*
Richard L.
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Making gaskets.....
Back in the day, and even now, I have no hesitation to make a gasket from whatever is to hand, Cereal packet card is good, as is 6 pack card. My dad showed me how to tap the card against the sharp edge of the casting, producing a perfect cut and a good copy of the genuine article. I was gobsmacked by this make do and mend philosophy, how simple and convenient it was, and used stuff to hand. That was a long time ago.
These days I don't attempt to cut out bolt holes with a drill or blade, but instead tap the dome head of a coach bolt into the card over the hole. Put the bolt in the hole to keep the card in place and tap round the casting with the narrow end of a carpenter's hammer and see your Corn Flake gasket emerge in all its glory.
The cost of a full set of gaskets these days is poor value, so for the odd gasket make your own. Hylomar is still my jointing of choice, but bathroom silicone used sparingly is also OK in the right place.
I doubt whether many folks make their own now, so another skill to be lost.
Swarfy.
A note of caution! Not all silicones are the same. The ones with acetic acid (the vinegary smell) are corrosive. Just look at a silicone gun. Personally I only use the gasket specific silicone but each to their own.
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I cheated. Managed to get a nitrile primary cover gasket (1.6mm thick) off Fleabay for £7.70 which is a bit cheaper than the paper ones on there. Nitrile bonded cork for the size I needed was about £12 - primary cover is roughly 45cm long and about 25cm high I think. Having said that, I may buy a smaller size sheet and cut out some washers for the fuel tap and primary cover drain plug. I reckon the sump plate would also benefit from a thicker gasket.
Need to be careful with nitrile washers for fuel as it degrades it - nitrile bonded cork seems ok though.
Comments welcome, don't shoot me down in flames guys. *eek* *beer* *beer* *beer*
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We should digitize the gaskets and get them laser cut. The hard work is the digitizing but after that the gaskets are easy with the right kit (which I don't have). I do make my own gaskets by hand, but I'f i could press a button and cut a chaincase gasket or timing cover i would.
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Worty, you are right nitrile and petrol these days dont mix, the petrol eats into and swells the rubber then the rubber effectively melts away, anything that touches petrol now needs to be viton (seals) or flouro lined tubing.
Unleaded fuel was bad and now ethanol added, its even worse for fuel systems...
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Worty, you are right nitrile and petrol these days dont mix, the petrol eats into and swells the rubber then the rubber effectively melts away, anything that touches petrol now needs to be viton (seals) or flouro lined tubing.
Unleaded fuel was bad and now ethanol added, its even worse for fuel systems...
Now I'm asking the question, will the nitrile part of the nitrile bonded cork deteriorate? *dunno2* The sheet was sold as fuel and oil resistent.
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Wotcha.
Although aimed at the "arts and craft" market - THIS THING (https://cricut.com/en-gb/)does a good job of gasket making too.
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I like that, looks interesting! I wonder if you could scan a cover to get the shape?
I was putting Hylomar on a joint last week and getting as much on me as the joint face, there must be a better way.
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I have seen those cutters including the Brother Scan and cut and thought they could be good for cutting out gaskets. I think I found that the cost of the device and the paper would make them quite expensive compared to those bought. I am fairly local to Draganfly and so can go and get them when required and they have been pretty good.
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Worty, you are right nitrile and petrol these days dont mix, the petrol eats into and swells the rubber then the rubber effectively melts away, anything that touches petrol now needs to be viton (seals) or flouro lined tubing.
Unleaded fuel was bad and now ethanol added, its even worse for fuel systems...
Now I'm asking the question, will the nitrile part of the nitrile bonded cork deteriorate? *dunno2* The sheet was sold as fuel and oil resistent.
Worty, I cant tell you if the product you have is any good or not for gaskets, I would think that it would be fine in that situation, but dont know. What I do know from my Ford eng'g days, was that when ULP was introduced we had to upgrade all our fuel lines and gaskets that were in contact with petrol, then upgrade more when Ethanol fuels were introduced - viton was the only solution for O rings used in taps and valves though....
Also, what I do know from personal experience with ethanol fuel inadvertantly used on my (chinese made, Honda copy) generator, is that it expanded the seals in the fuel tap and locked them closed. I had to remove the fuel tank and pipes and clear the ethanol fuel, then replace the tap and lines, all good since :!
NB it does say in the handbook NOT to use ethanol fuels, when I read it to see what could have happened *sad2*
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The trouble is its hard to avoid. Its in diesel too but not so publicized. All the seals in my CAV injector pump went hard and it leaked like a sieve. Some years ago I converted a car to run on vegetable oil. It's very chemically aggressive despite being a food stuff and dissolves all sorts of things, it even attacks copper. There's this idea that because it comes from a plant its benign, not so.
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And last week the Amal premier on my A7 was leaking like a sieve. Turns out the pipe banjo fitting is sealed with a thin rubber washer. Or was, as the fuel had destroyed it.
A good old traditional Amal red fibre washer soon sorted it.
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I like that, looks interesting! I wonder if you could scan a cover to get the shape?
Wotcha.
Yes you can scan things.
If you have a gasket set, just scan those.
The only one that is tricky is the primary side gasket - you need an A3 scanner.