The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: dosser on 29.04. 2025 14:28
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now i tried for 8 hours and 3 rocker-gasket later and stil miss one, after i changed gaskey on the cylinder, is there a way or do i have to get the alignment tool, cant find it in denmark and im in a litle hurry for a trip.
Sorry for my poor english, im from Denmark.
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Start by making sure each pushrod is correctly positioned in the centre of its cam follower. You need to slack off all the tappet adjusters.
Put on the rockerbox, leave it raised slightly on the four bolts then use torch and mirror to look inside.
In turn move each pushrod under its cup, using a wire hook, then lower the rocker arm into place onto the pushrod tip and tie up with a rubber band. This keeps the arms on the pushrods. Then lower the rocker box down, screw the adjusters lightly to remove all play, tighten the rockerbox down and remove the rubber bands. Make sure the engine will turn over by hand, then tappet adjustment can be set.
That's one way of doing it.
Having three hands helps, Gynaecologists have no problem.
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Hi, I found after much effort, there was always one pushrod very slightly high as is came onto the cam. when I made sure that was an inlet push rod it went on first time. See https://www.a7a10.net/forum/index.php?topic=13293.msg170343#msg170343 (https://www.a7a10.net/forum/index.php?topic=13293.msg170343#msg170343) plus other earlier posts in that thread by me.
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i dont use the tool , I find it easier to put a dab of grease on the ends of each push rod and use a curved dental pick and flashlight to position them .......might not need the flashlight if your eyes are younger than mine *smile*
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Well, thanks, i did almost like you did, now i must have a cold and wait until tommorow (says my wife LoL)
Then i give it another 8 hours ;-)
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i dont use the tool , I find it easier to put a dab of grease on the ends of each push rod and use a curved dental pick and flashlight to position them .......might not need the flashlight if your eyes are younger than mine *smile*
I do the same, but definitely with the rockers slackened right off.
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A couple of things:
- I made my own as shown here: https://www.a7a10.net/forum/index.php?topic=368.msg3492#msg3492
- Regardless of using the comb, I always check using a stick mirror to look up to the top of the rods to be sure they're in the rocker cups.
- I use a "flashlight" with the mirror. Mentioning this just in case "torch" does not have the same meaning in Denmark as it does in England. That could have an unfortunate result. :o
- You could ask a friend to help.(https://openclipart.org/detail/338363/nosferatu-shadow-with-long-fingers)
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The tool is really cheap from Fecked, postage shouldn’t be expensive.
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G'day dosser.
Ahhh, our favorite job, not.
I use the comb and rubber bands but have done it without the comb and just hooks.
With the adjusters backed right off and the rubber bands holding them up.
Something that may make it easier for you is to make dummy studs. Get the box up over the head and screw in the studs into the bolt holes. You can then slide the box down square to about 10mm up. Start with the ex side first, push down on the rocker and position the rod into the cup, the rubber band hols it there. Then the same for the inlets. Push the box down and remove the studs. bolt it up, adjust the tappets, job done.
I've done it hundreds of times, some take minutes some take an hour!
Best of luck.
Cheers
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I wonder how they did this on the production line at BSA ,fiddly time consuming job
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I have often wondered why they did not produce a head gasket the same as the A7 Longstroke motors had. Those gaskets have holes where the pushrods come up rather than one big hole. I couldnt find a decent picture of one but the attached pic will give the general idea.
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G'day Fellas.
How much easier is the Trihard T120 system with two separate rocker boxs and gaskets with push rod holes.
Cheers
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Yes as much as we all love our BSA's the rocker box design wasnt one of their better efforts.
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After 1 1/2 hour this morning, i THINK i got it LoL, now ill see if i can start after reassambly.
Thanks for all the help.
A happy Dane and we stil got Greenland!
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Some folks use the ARIEL Huntmaster rocker box with its central access. As Ariel was part of BSA the Huntmaster engine is all A10 inside, but with its own crankcase castings. Cylinder head is very similar to A10, but with exhaust pipe stubs. These heads often appear on ebay, listed as A10 by ignorant sellers, as do the timing covers, again just a bit different.
Some attempt to keep the two marques apart, or maybe the cost accountants and marketing men ruled against using a common rockerbox.
A7 Longstroke is easy with the Triumph design influence carried over. Reckon company politics won the day and we have suffered ever since.
Swarfy
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OK so here is my hot tip. In preparation for the job I "glue" the gasket to the rockerbox 24hrs or so before assembly, I use Threebond which dries and is better than silicon. It (or they) can be precisely positioned, nothing more disappointing than an oil leak or misalignment stopping a bolt going in correctly.
Chris
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G'day Chris.
So you only glue one side of the gasket?
I'm just about to lift the rocker box off the Cafe today. A small leak front left so I'll re-tension the head while I'm in there. Lucky I have spare gaskets, I make my own 6 at a time.
Cheers
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Hi Musky, Guys. Yes I find using Threebond 1215 or Loctite SI 5699, both setting types of sealant and better than silicone, on the rocker box side of the gasket only, stop it creeping and make assembly so much easier.
I apply a reasonably even amount and let it completely set, now the comb can be used and other tools for the tricky bit without every thing descending into a mucky mess as often happened to me before this method. I have never reused a rocker box gasket so I don't grease the other side. Along with the other points in this thread, and I particularly note Angus's about the inlet pushrod, which could be the reason I sometimes find it difficult, from now on it will be a piece of cake.
Best Regs
Chris
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The one piece gaskets from srm are excellent I have yet to have one leak.
As I have said here before I rarely use the comb or eleastic bands and I never loosen the tappets unti lI have to adjust them. One of the inlet push rods at full height the other 3 all lo and just flip it on. If you have an alloy head its a lot more difficult and as for those two front nuts on the rocker box I find them harder than locating the push rods by a long way. I have an alloy head on my plunger with the head steady tubes going under those front nuts and they are a right f****** b******
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I was surprised in the end after all the doom laden comments on the rocker box fitment. I didn't have the comb and kept it simple.
Undid the rocker adjusters and wound everything out. Stuck my gasket onto the rocker box first with 'Permatex Aviation' gasket goo, very much a Wellseal type product. It doesn't set but goes very tacky if you let it dry. Dropped my modified VW pushrods into the followers checking everything was seated properly with a spin of each pushrod and a gentle lift, you can feel the suction if the ball end is properly in the cup. I had prepared the rear studs earlier with hex key sockets in the end so they were engaged but sitting low which helps when maneuvering the RB into place.
I sat the pushrods into what looked like the best orientation to match the rocker cups and then fiddled the RB into place. I then found I could find each pushrod with my fingers and feel that the ball end was in place. I even deliberately misplaced one to feel the difference and you can!
Then took up the slack on any tappets that could be snugged up just to hold everything and then lightly hand tightened the holding down bolts and gently turned the motor over (plugs out) making sure each pushrod stayed engaged, again by feel. Once the RB was fully down I wound up the rear studs and fitted the nuts then the front nuts, which are tricky but glueing them to my finger with a dob of grease seemed to help.
Then it was a case of turning the motor over and going through the tappet setting procedure, torquing all the fasteners, then repeating the tappet setting and finally tightening the locknuts. All done with no comb, rubber bands, mirrors, bits of wire etc. really simple but to be fair I am still pretty flexible and have long fingers! ;)