Author Topic: A10 Gaskets  (Read 2145 times)

Offline Brucie64

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A10 Gaskets
« on: 05.08. 2010 12:02 »
Iv'e just noticed I have a slight oil leak that seems to be eminating from the join between my head and rocker cover. I have tried to tighten the rocker bolts up a little in an attempt to stem the weeping but to no avail so I will just have to whip the cover off and replace the gasket(s).  Is it advisable to buy the rocker cover gasket kit "R329" and change them all together or is it ok just to change the rocker cover gasket itself "67-0278"?
Bruce
Spitfire
UK

Offline muskrat

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Re: A10 Gaskets
« Reply #1 on: 05.08. 2010 13:23 »
G,day Brucie64,
                          Your kidding, a leak from there!!! Ah, they all do that sir.  *smile*
But really yes you will need a new gasket, and while your there get a comb (your hair's a mess). Oh I'm full of it tonight.
You are about to undertake one of the most feared jobs of A7/10 mechanics. Use "search" to find quite a few posts on the subject.
Also in the future any time you touch the rockerbox, head or cylinder base nuts you should check and adjust the valve clearances.
Have fun.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline A10Boy

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Re: A10 Gaskets
« Reply #2 on: 05.08. 2010 13:34 »
To be honest, if its only a weep then it will most probably still weep after all your hard work. Obviously, if it's a significant leak then it needs doing but it will probably still leak.

Check the rocker oil feed banjo bolts and washers, they often leak, oil runs down and makes it look like a rocker gasket leak.
Regards

Andy

1958 Super Rocket
Plus
1974 Kawasaki Z1a
Yam XJR 1300

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Re: A10 Gaskets
« Reply #3 on: 05.08. 2010 15:27 »
dust the joint with concrete.
Leave it over night to set.
Bike Beesa
Trevor

Offline RichardL

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Re: A10 Gaskets
« Reply #4 on: 05.08. 2010 15:51 »
Not having the fingers of Vladimir Horwitz nor training as a dentist, I have resolved that the pushrod comb is the way to go for me. If you lay the gasket on the head the sealer between them will not be disturbed. If you use a bit excess sealer on the gasket top surface, there should be enough to do the job (to the extent expectable) after it is disturbed by the removal of the comb. If you get the pushrods set while the box is still slightly off the head you'll have less sealant on the comb. There is just enough space between the intake and exhaust sides to remove the comb. I find it good to slack off the valve adjusters, but that calls for a bit of care to assure the pushrods in their cups.

Then, when it's all done, as has been said, it might still leak. You might recall the recent discussion about a shock-absorbing head steady describing rocker box leaks as a function of vibration transmitted to the joint via rigid head-steady hardware.

Well, tired thumbs and plane about to board.

Cheers/Bye

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Offline bonny

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Re: A10 Gaskets
« Reply #5 on: 06.08. 2010 20:35 »
i know that tri-cor are doing copper gaskets for the rocker boxes for the triumph twins , i wonder if they would help on the bsa a's .

Offline muskrat

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Re: A10 Gaskets
« Reply #6 on: 06.08. 2010 22:18 »
G'day Bonny,
                     funny you should mention that. I just bought a set of copper rockerbox gaskets on ebay US. $53AU landed, should be here Monday.
I also saw he had a head gasket on there and said he can make the bore size or thickness to your requirements. As my motors are through bolted I have to make my own head gaskets and have trouble getting material, I emailed him a drawing. He got back with a quote. $20US to program the cnc mill and $22US each at 1mm thick. I think this is quite a good price. I will be ordering 1/2 dozen. 310113215134 is the head gasket item, and would be good for members who want to try a thicker than std to drop comp ratio. I will post a topic when they arrive.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline bonny

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Re: A10 Gaskets
« Reply #7 on: 06.08. 2010 23:00 »
evenin' muskrat

it will be interesting to see if they work , i know on the triumph the gaskets tend to be squeezed out of the joint and they have a hard time with the heat , especially the exhaust side, and i hear stainless steel gaskets are being made too , i think the copper being softer would seal better though.

Online BSA_54A10

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Re: A10 Gaskets
« Reply #8 on: 07.08. 2010 11:50 »
Well you could go the way of Rolls Royce.
They use sheet aluminium with a sheet of klingegrit on the top & bottom.
Leaks from that seam usually can not be fixed so easily as what usually happens is that owners tighten the nuts, more & more and this extrudes the aluminium and distorts the joint face.
Even worse is when there is a leak from just one corner so the owner just over tightens the one nut / bolt.

The rocker case is aluminium and the head is cast iron both of which have different expansion rates so they will move with respect to each other at the joint face every time they get hot and every time they cool down.
BSA made this even worse by putting the rockers inside the case so there is also a whole raft of forces trying to stretch the joint apart or push the valve down whichever yields first.
To allow this movement BSA fitted a relatively thick and soft gasket to the face.

To get a good oil tight seal. the first step is to make sure that the joint faces are flat & true so they should be lapped ( a bit hard with the head if the valves are in there ).
The glue the gasket to the cover with a non hardening sealant like Hylomar.
Use a soft gasket with high ( or extreme ) temperature grease between the gasket & the head to facilitate movement.
Then tighten it as if it was a head, from the middle to the outside from alternate sides to allow it to spread.
Now most important so I will shout.
ALL THE NUTS & BOLTS MUST BE DONE UP TO THE SAME TENSION SO THERE IN MINIMAL CHANCE OF DISTORTION.
The actual number is not particularly important , What is important is that they are all the same.

Do this and it will not leak. Provided that the breather is working properly and you are not getting excessive crankcase pressure in the head.

If one comes loose , back them all off ( in reverse order ) and do them all up again .

I use black Klinger grit or if I can not find the black then the pink which is a little softer.

Bike Beesa
Trevor

Offline olev

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Re: A10 Gaskets
« Reply #9 on: 07.08. 2010 12:05 »
Wish you luck, Musket,
The 'Union Jack' ad in Just Bikes has an ad for triumph gaskets.
quote: "special steel reinforced rocker base gaskets, won't leak like copper types"
but what would a triumph riding pr**k know anyway?
ad also says
 
"Coming soon genuine Smiths GPS SPEEDOMETERS in KPH or MPH 6V or 12V positive or negative earth, deadly accurate grey face or black face & even chronometric dial types so no more drive or cable problems ever (don't need either) mount as original, sole world wide distributor, undergoing tests for reliability, orders to be placed early if interested."

that sounds interesting. hate to think what its worth though.
cheers

Offline RichardL

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Re: A10 Gaskets
« Reply #10 on: 07.08. 2010 12:45 »
Trevor,

A few questions, if you don't mind.

  • Wouldn't non-hardening Hylomar on the bottom of the gasket make a better seal than grease and still allow for the small amount of movement?
  • Are you using a torque wrench for this job and, if so, what value to do you use?
  • Is it even possible to get a torque wrench onto the inside bolt and the underside nuts. (On the latter, I must think "not possible". I have used a fish scale on the end of a spanner in such cricumstances in the past, but it seems overkill here.)


I can't recall if I did it wrong or remembered it wrong, but the method of sticking the gaskets to the rocker box first, instead of the head seems much better than what I said earlier. In so doing, the comb sits on the clean head surface until just before box touchdown and, likely, stays much cleaner while disturbing sealant (grease?) less.

I always appreciate your technical explanations.

By the way, how do you feel about cheap aftermarket parts sold on eBay?  ;)  *roll* *lol* (Just kidding.)

Richard L.

 
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Offline bonny

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Re: A10 Gaskets
« Reply #11 on: 07.08. 2010 13:46 »
Wish you luck, Musket,
The 'Union Jack' ad in Just Bikes has an ad for triumph gaskets.
quote: "special steel reinforced rocker base gaskets, won't leak like copper types"
but what would a triumph riding pr**k know anyway?
ad also says
 
"Coming soon genuine Smiths GPS SPEEDOMETERS in KPH or MPH 6V or 12V positive or negative earth, deadly accurate grey face or black face & even chronometric dial types so no more drive or cable problems ever (don't need either) mount as original, sole world wide distributor, undergoing tests for reliability, orders to be placed early if interested."

that sounds interesting. hate to think what its worth though.
cheers


those steel reinforced gaskets are the ones triumph fitted as standard and they do leak , so he's talking rubbish there , tri-cor in england are making the copper type and i have heard good things about them.     

Offline iansoady

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Re: A10 Gaskets
« Reply #12 on: 07.08. 2010 14:29 »
Velo singles have a similar layout - separate rocker box, although there of course it's on an alloy head. The proper gasket is a wire reinforced item which if fitted properly doesn't leak (well mine didn't anyway). It also provides a positive spacing of the rockerbox so tappet adjustment doesn't drift.

There are dire warnings about using softer gaskets for that application so perhaps a reinforced gasket would be useful on our A10s.
Ian.
1962 Golden Flash (arrived)
1955 Velo Viper/Venom (departed)
2004 Triumph Tiger 955i (staying)

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Re: A10 Gaskets
« Reply #13 on: 07.08. 2010 14:57 »
Quote
Wouldn't non-hardening Hylomar on the bottom of the gasket make a better seal than grease and still allow for the small amount of movement?
Are you using a torque wrench for this job and, if so, what value to do you use?
Is it even possible to get a torque wrench onto the inside bolt and the underside nuts. (On the latter, I must think "not possible". I have used a fish scale on the end of a spanner in such cricumstances in the past, but it seems overkill here.)

No Hylomar to stick the gasket and grease to leave a clean face.
You can even work the grease in with the cover 1/8" proud of the surface as it won't harm the engine.

I have a 6" 3/8" drive torque wrench, just perfect for the job particularly when used with the very thin walled Hazet sockets.
The nuts on the under side just have to be by feel and I would be going around the 30 ft/lb on an Iron head and 20ish on an alloy head . The actual number is not really important, keeping it constant is. One of my favourite tricks with "brand" tool wankers was to put 2 torque wrenched onto a short length of allen key and tighten them. They never signal together.

Pop your torque wrench on one and see where the spring washer flattens. You should not go much more than another 10% after that or the spring washer becomes redundant and you may as well have used a flat one.

When working on motorcycles and particularly into alloy it pays to have a small tool but I don't think I will sell many T-shirts with that on them. But you get really good feel with short spanners ( that one might work better ) and the 6" is fairly close to the length of some rings I have. 
Bike Beesa
Trevor

Online chaterlea25

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Re: A10 Gaskets
« Reply #14 on: 10.08. 2010 10:54 »
Hi All,
Heres my ?0.02 opinion again *smile*
I would think there is merit in the solid gaskets on Triumph engines as some types have the head bolts going down through the rocker boxes, so the gaskets have to cope with the higher torque value and the expansion issues
The Velo gasket is a mighty piece and is reminiccent of the auto exhaust manifold gaskets of yore
(reinforced Hallite?????)

Most if not all gaskets supplied for the A 7/10's are made of a very soft material and with the narrow mating faces are almost cut through when tightened *sad2*
I buy sheet "klingerite" or similar from an engineering supplies place or direct from Walkers
this is more fibrous and a lot tougher, you need sharp punches to make clean holes in it

Anyway, If you go to my "head steady" topic you will see how I cure the dreaded rocker box leaks *smile* *smile*

Cheers
John O R
1961 Super Rocket
1963 RGS (ongoing)