Author Topic: More valve spring /head questions...  (Read 350 times)

Offline Truckedup

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More valve spring /head questions...
« on: 18.08. 2020 15:37 »
 I have ordered a parts manual, but I have some questions...what I have is a nice 67-1066 iron head for the 1961 Super Rocket lower end...I assume the big fin 1066   head is the best of the iron heads? Does this iron head use the same valve springs as the  aluminum head ? The iron head uses no lower springs cups and the alloy head does?
  I have several  successful Triumph 650 land speed racers..A  Triumph is not a BSA but sorta the same and I am not afraid to make modifications if necessary...
1961 Super Rocket, 79 Triumph T140D, 96 Ducati 900M

Online bsa-bill

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Re: More valve spring /head questions...
« Reply #1 on: 18.08. 2020 16:44 »
Hi there and welcome
as far as I know iron heads and alloy heads use different valve springs,  iron head also does have lower spring cups, also alloy head uses different valve collets but that would not matter if your using the iron head valves.
Might be more differences if your engine is a rocket (camshaft perhaps although number will be stamped on the end of it)
interesting project
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline Swarfcut

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Re: More valve spring /head questions...
« Reply #2 on: 18.08. 2020 20:15 »
Hi Tony.  67 1066 is the casting number. When your parts book arrives you'll find this number doesn't appear, only the closely related part number for a complete cylinder head assembly. This is true across the whole of the BSA parts listing. Pistons confuse even more as the  number stamped on the crown is close to, but not exactly, the number in the parts book which is the number for a fully loaded piston.

 BSA only used two styles of A10 Iron Heads. Early  "thin fin" used on rigid and plunger models, then with the swinging arm frame came a similar casting but with a bigger fin area....your 1066 type.

 Alloy heads and cast iron heads have different valves, collets, caps. They also use different head bolts. Valve springs are an exception, Alloy Head A7 Shooting Star springs  are the same as iron head type, but A10 Rocket Alloy Heads have their own springs.  Iron head common hardware parts are  broadly the same from start to finish and all head types have lower spring cups. Valve collets, caps and springs are common to A7 and A10 Iron Heads.

 Detail changes came as the engines were developed over time.

 All will be revealed when your parts book comes. Camshaft number is stamped on the end of the cam, and can only be seen when the cases are split to expose the blind bush end of the cam in the drive side case.  To split the cases, the camshaft can remain undisturbed, it does not hinder dismantling.

Swarfy.

Online JulianS

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Re: More valve spring /head questions...
« Reply #3 on: 18.08. 2020 20:42 »
The 1960 on A10 iron head the inlet port increased from 1 1/16 inch to 1 1/8 inch. The part number for this later head was 42 0180.


Offline muskrat

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Re: More valve spring /head questions...
« Reply #4 on: 18.08. 2020 21:27 »
G'day Trucky.
It can be a "mine field" up there. Quite a few differences between iron and alloy heads. One of the main differences is the inlet port on the iron head sits flat where the alloy head has a downdraft, meaning the carb sits higher and at an angle. Your iron head will fit on the SR motor (with the correct iron head bolts) but there may be some alignment problem with the carb to airfilter  *dunno*.
All alloy heads (except the A7SS) as mentioned by Swarfy use different hardware to the iron heads. Not a good idea to tr and mix and match.
I did with the last Cafe rebuild by putting SR valve gear in an A7SS head. Ended up using SR valves and collets into SS springs and cups (cups had to be machined to take the SR collets)  *pull hair out*
Till your book arrives the best parts list is online at Draganfly https://www.draganfly.co.uk/bsa/bsa/a710--b3133--c101112--m202133
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Truckedup

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Re: More valve spring /head questions...
« Reply #5 on: 18.08. 2020 21:39 »
 Thanks guys..If I could find a decent alloy head it would be used...
1961 Super Rocket, 79 Triumph T140D, 96 Ducati 900M

Offline chaterlea25

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1961 Super Rocket
1963 RGS (ongoing)

Offline Truckedup

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Re: More valve spring /head questions...
« Reply #7 on: 18.08. 2020 23:28 »
Hi Tony,
Alloy heads in decent condition go for decent money  *eek*
Here is a link to one in USA,
 https://www.ebay.co.uk/itm/1958-1963-BSA-MOTORCYCLE-CYLINDER-HEAD-ALLOY-A10-ROAD-SUPER-ROCKET-SPITFIRE-650/133490134395?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

John
I just threw a $470 bid on the head and still out bid....Ouch....I look again just before it ends...
  I've built quite a few bikes and need to be realistic, besides having the alloy head on the engine  just because it matches the DA10R lower end....will it really matter for occasional road use by a 73 year old rider  ;) *smile*
1961 Super Rocket, 79 Triumph T140D, 96 Ducati 900M

Online berger

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Re: More valve spring /head questions...
« Reply #8 on: 18.08. 2020 23:38 »
I will stick my neck out and say NO , just think of the spare beer tokens *beer* *beer*

Offline muskrat

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Re: More valve spring /head questions...
« Reply #9 on: 19.08. 2020 00:20 »
A little more info on alloy heads. http://atlanticgreen.com/a10alloyhead.htm
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Swarfcut

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Re: More valve spring /head questions...
« Reply #10 on: 19.08. 2020 08:59 »
 Tony.   As the alloy heads have a certain mystique, everything about them carries a premium. They certainly are a thing of beauty, but to my mind a little fragile in the fin department and need to be treated with care.
 A working bike with a cast iron head will be fine. You will find plenty in the bottom end department to soak up any surplus cash....Have a good look around the forum before you even reach for a wrench, these motors have a few little tricks for the unwary.

 Musky. Thanks for the link. Very informative and shows the various types in all their glory.

 Cheers

 Swarfy.

Online JulianS

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Re: More valve spring /head questions...
« Reply #11 on: 19.08. 2020 09:45 »
Swarfy I agree

12 months ago my alloy head developed a crack at the front between the bores, non repairable, plus over the years it had been skimmed to death, leaked from the rocker boxes and of course, the rocker box is particularly difficut to get on with the 650. The prices of alloy heads is frightening and no guarantee that it will be any better than the one you have. I have had 3 alloy heads since 2007.

Solution was a £40 iron head from ebay plus a new set of head bolts. The pipes fit nicely in iron head, no sealer. Had a set of Road Rocket (small inlet) valves which I fitted together with the Eddie Dow type top collars, spring seats and springs and the big monobloc (with smaller main jet) from the last alloy head and it works OK and much better after fitting low comp pistons back in January.

Not ideal visually on a DA10R bottom end maybe but practical.

Offline Truckedup

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Re: More valve spring /head questions...
« Reply #12 on: 19.08. 2020 12:42 »
 The friend I bought the basket case from has two bolt on manifold alloy heads. One real nice, the other just ok...He refuses to sell one to me, damn. 
1961 Super Rocket, 79 Triumph T140D, 96 Ducati 900M

Offline Butch (cb)

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Re: More valve spring /head questions...
« Reply #13 on: 19.08. 2020 12:54 »
My old iron head has a soft tune and is lovely to ride.

I know that Roger at Cake Street did have a store area chock full of alloy heads, don't know if he has been selling them over the years to fund any sort of retirement.

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Offline chaterlea25

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Re: More valve spring /head questions...
« Reply #14 on: 21.08. 2020 00:14 »
Hi All
The Alloy head I linked to above went for just a few dollars more at $482 but who knows what the winner had bid on it?
It included a rocker box and all the valve gear
It looked to be a good deal to me  *????*
I'm sure I paid about $400 for the head I got from USA some years ago (+post)

John
1961 Super Rocket
1963 RGS (ongoing)