nigeldtr
A's best friend
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« on: 21.11. 2011 22:12 » |
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Well since rebuilding my plunger A10 engine I have enjoyed to old girl no end. Runs a treat, lovely and reliable. I was out and about and noticed oil running down the back of the barrels, not too much but a leak. Anyway, no obvious place where it could be coming from? I took the tank off and had a closer look and could see the gasket had blown out under the back of the RHS exhaust valve rocker box. Rockerbox off and could see no real issues then I thought about doubling up the gaskets. I also decided to quickly check the bolts in the holes and opps crud stopping the bolts going right down – fell for the same mistake again! I Forgot to check the new bolt length and to clear out the crud. Run a plug tap down all the threads couple of times and have blown out the crud, bolts now go all the way down! Should I still double up the gaskets – what do you think?
Regards
Nigel
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1951 Golden Flash (engine now rebuilt) 1953 M21 a pain to start and 1961 GF that is turning into a black hole!
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bsa- bill
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« Reply #1 on: 21.11. 2011 23:38 » |
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Hi Nigel - it worked for me for a short while, the problem is the gaskets we buy do not cover enough of the head to Rocker box mating surfaces at the front of the rear rocker compartment ( just as you say)
Members here have copper gasket made something I'm looking at, at the moment my Rocker box is oil tight, I managed this by making my own gaskets from gasket card.
Photo below will show where the bought gasket are deficient and my home made effort
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All the best - Bill  |
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BSA_54A10
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« Reply #2 on: 22.11. 2011 11:06 » |
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Get some solid copper ones from Lanni at CoppergasketsRus.
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Bike Beesa Trevor  |
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Topdad
bob hebdon
A's best friend
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Posts: 191
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« Reply #3 on: 22.11. 2011 12:42 » |
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Or Ligtning spares in Sale Ches make there own wider gaskets which I've heard good reports about ,regards bob H.
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" rules are made for the guidance of wise men and the blind obediance of fools"
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bsa- bill
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« Reply #4 on: 22.11. 2011 15:31 » |
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that's good to know Topdad, cheers - will save my scissor fingers
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All the best - Bill |
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a10gf
West Coast, Norway
Forum Oracle
Karma: 11
Posts: 1099
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« Reply #5 on: 22.11. 2011 15:53 » |
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Maybe check that the covers\surfaces are straight and well mating. If parts are out of shape or damaged, the gasket is asked to do lots more work than it should, ie filling in and compensate for more than is possible, and very thick gaskets opens for the risk of over-tightening at the bolt positions, thus bending things even more. Good mating surfaces + very thin gaskets have always been my goal. Just some opinions.
I've made quite some gaskets, the best results came from putting ample amounts of some ink on one of the surfaces (when possible), then pressing it against the gasket sheet and when satisfied with the print, cutting it with scissors, scalpel or whatever was best, & making holes with a hole punch (the outside one can draw with a pen, it's the inside + exact positioning of holes that benefits from the ink print). This made it possible to make gaskets covering the max possible surface available.
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A10 GF '53, Triumph 900 Legend, Yamaha XT500  Norway - Bergen |
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nigeldtr
A's best friend
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Posts: 195
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« Reply #6 on: 22.11. 2011 20:22 » |
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Thanks Guys really appreciate the tips - this site is great!!
Regards
Nigel
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1951 Golden Flash (engine now rebuilt) 1953 M21 a pain to start and 1961 GF that is turning into a black hole!
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muskrat
Forum Oracle
Karma: 25
Posts: 1882
Lake Conjola NSW Oz
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« Reply #7 on: 22.11. 2011 20:32 » |
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G'day Nigel,
about once every 2 or 3 years I buy a gasket kit and use them as templates to make my own from either 0.4 or 0.8 mm jointing paper. Doubling the gasket is not a good thing. a10gf is on the money about flat surfaces and I have had success with the copper gaskets from Lanni.
Cheers
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Only young once, immature forever. Now how can I make this go faster. '51 A7 plunger, '57 A7SS now A10, '71 A65 Lightning (gone to god) '76 XT500, '83 CB1100F, next project a '64 A65. |
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dpaddock
NC, USA
A-Clairvoyant
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Posts: 430
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« Reply #8 on: 11.12. 2011 01:30 » |
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IMO, don't use the gasket (much less two).
I believe it was Roland Pike or Golland who witnessed severe rocker box movement in the lab under load, which is why BSA cast the rocker box with the head as a single unit for many years ( at least with the Gold Star).
I've used a decent non-silicone sealer for years and found it completely satisfactory.
David
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David '57 Spitfire  |
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