Author Topic: A10 A7 Alloy Barrel and Twin Carb Alloy Head  (Read 553 times)

Offline zurferjoe

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Hi out there .Just made the first casting for my A10 alloy barrel project . Fed up with the iron one and its fragile nature !! The barrel at first will have iron liners then Nikasil Chrome bores , to test which one is the best . im also making a twin carb alloy head for it as well , as the motor needs to breath a lot more ! These pictures are of the barrel in a raw state and will be machined on the outer flanks of the fins to look like the originals but 4 kilos lighter !And still retain a nice healthy THICK flange 18mm !  I will keep you up to speed with the progress .
The older you get , the faster you were !First picture of the BSA A10 alloy barrel !!

Offline Swarfcut

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Re: A10 A7 alloy barrel
« Reply #1 on: 21.11. 2018 17:32 »
 JoJo..... Good work there fella.  A six fin barrel to confuse the rivet counters. Guard that pattern with your life! Even better, put on your own fake patent number.

   Swarfy.

Offline zurferjoe

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Re: A10 A7 alloy barrel
« Reply #2 on: 21.11. 2018 17:53 »
Hi Swarfy  . you aint wrong there ! Been there done that ! Hope to make the beast fly ! Bonneville next year ! With a 650 and 750 motor A10 all the best Harry
The older you get , the faster you were !First picture of the BSA A10 alloy barrel !!

Offline Sluggo

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Re: A10 A7 alloy barrel
« Reply #3 on: 21.11. 2018 18:23 »
Clearly sandcast?  Which alloy did you use?  Some pours better than others. Be interested in your process and progress.  I know a local guy who runs a small lot foundry and does mostly aluminum but does some ornamental brass too.  A couple tool and die makers and machine shops will do batch runs and take in their dies and commission batches of parts to be made.  Sir Eddy was using him for his finned Norton parts

(Funny story about that and Jackie from Unity Equip got her knickers in a twist over it)

If you want to get into the Norton business, the dies and molds for the Norton VR880s are still up for sale.  Heads, Barrells, cases and trans.  (I have 2 VR880 cases)

I will be interested how you get on with machine work, the flange DOES look nice and satisfyingly thick however it does not seem to come out very far, How are you going to secure them? Stock studs and nuts or are you going thru & thru with longer bolts from the head to the cases??  (Thats probably stronger anyway)
I have seen some sprinter/race Triumphs with turbos and superchargers that did that.
By securing the entire top end in one lump instead of piece meal it kept more stable.

Love to hear details on your race engine builds.  (Upvoted)
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Offline zurferjoe

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Re: A10 A7 alloy barrel
« Reply #4 on: 21.11. 2018 18:42 »
I will be using Alloy 388 ANS/AA , Ive used it in my other projects and am very happy with its machining quality after hardening .I am using my own machine program ,on my Cnc machine
The older you get , the faster you were !First picture of the BSA A10 alloy barrel !!

Offline Sluggo

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Re: A10 A7 alloy barrel
« Reply #5 on: 21.11. 2018 18:46 »
Ill add, spent a bit of time re-engineering old Brit Iron... There was 3 of us that started the Land Speed record racing project for a Norton.  We went for the 500 pushrod class and it took many years.
This is the engine in a earlier variation.  Note the cyl, While Sir Eddy was a master tool & Die maker and there was no casting he could not manage, He felt that a solid Billet block of 6061 was the best bet, and made it on his Mill.  The early design used BSA lifters as well.   We looked at sleeving but opted for a coated wall to keep the tolerances tighter.  YRMV but with a liner you have to run a looser wall clearance with the pistons.
Pistons were custom made forged (First batch was defective and they had to make us more)
It wasnt Nicasil, but something similar.  I cant recall the vendor but can find it if you like.  Needless to say a lot of time was invested to get it right.
If you look close Eddy cut small grooves in the fins and inserted small strips of alloy that duct the air around the walls of the cyl as we found that heating & expansion was not uniform.

Nortons are backwards so the cyl was repositioned Desaxe, And the cases were stock Commando Combat cases which are stronger than the others. (The VR880 cases are even better but Eddy had bad blood with Dreer so that was not an option).  The first variation was a custom machined 270 degree crank made out of several donor cranks. A marvel of engineering and machine work by Eddy, but ultimately at the target RPMS it would not have survived.  (We got a LOT of good advice from others) So opted for a custom made Billet one piece crank and of course Carillo H beam rods.

Early version had a race car external segemented oil pump with needle bearings and custom lube points.  Later versions after Eddy died did away with the external pump, But the problem was the target RPMS with 11,000 so it was felt that the external pump consumed too much power. Sure did move some oil though!

You can also see in the picture the custom finned rocker covers and side oiler on the head that were all custom castings that Eddy used to make and sell. (He had a finned points cover he made also)

One last pix is the top secret cyl head tech we spent over a year on. Sadly later versions of the team went another direction (Several of us are not involved after Eddy died) But if you want details happy to share.  Read up on Singh grooves. (It WORKS!)
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Online muskrat

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Re: A10 A7 alloy barrel
« Reply #6 on: 21.11. 2018 19:03 »
G'day ZJ.
I through bolt my A7/10's. The four outside head bolts move outwards 1/2 hole.
Cheers
PS: Lani at Coppergaskets Unlimited has the head gasket on file.
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Muskys Plunger A7

Online RDfella

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Re: A10 A7 alloy barrel
« Reply #7 on: 08.01. 2019 16:25 »
Great work, zurferjoe. Nice fins, too. Know from when I made the pattern for my project (pair of single cyls with camchain tunnel) just what a bugger it is trying to get decent fins whilst maintaining sufficient draft angle so it'll release from the sand. Wouldn't fancy trying to make the pattern for a cyl head though.
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Offline zurferjoe

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Re: A10 A7 alloy barrel
« Reply #8 on: 08.01. 2019 17:36 »
Your not wrong there ! About the cylinder head ! Heres the the first sand cast core for testing .To check out shrinkage and  accuracy .Starting with 32 mm inlets for the 650cc and work my way up for the 750cc engine .The ports are just laid in at the moment and will be blended in when its all square .The combustion chamber will be wedged figure 8 shaped  ,and the head will have two sparking plugs per cylinder.
The older you get , the faster you were !First picture of the BSA A10 alloy barrel !!

Offline JulianM

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Re: A10 A7 Alloy Barrel and Twin Carb Alloy Head
« Reply #9 on: 09.01. 2019 11:04 »
Nice post and an interesting project, keep up the good work,

julian
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Offline zurferjoe

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Re: A10 A7 Alloy Barrel and Twin Carb Alloy Head
« Reply #10 on: 20.05. 2019 12:21 »
The new barrel , cleaner lighter and less the liner extentions ,not needed, ready for machining .
The older you get , the faster you were !First picture of the BSA A10 alloy barrel !!