Project 1065

[danma]

I have long thought a A10/A65 motor would be interesting and decided to give it a go and see how far I could get [expecting not very].

 This has been done before and there a few variations-Briz is heading the same way on a different route as well.I opted for the chew off and weld a lump back on route,  my brother is a welder [I'm not] so sticking slabs to cases was taken care of ,all I had to do was the rest.

 Various engine bits were measured and compared and paper was scribbled upon.
 A rough A65 barrel was attacked with a grinder until it would fit on my old A10 cases and bored to take a 850 78mm  Weslake  piston which had the same pin as the 500 73mm  nre piston I had previosly been running.
 
 Ccing the barrel and chamber revealed the compression would be woeful,even with a bathtub/squish chamber.Supercharger or domed pistons required--I'll worry about this later and move on.
 
 Purchased a set of A10 cases off ebay and did a bit of milling.

 Don't they look odd? I spent alot of time just looking at them and am glad I didn't buy a RGS just for a set of Da 10r  cases. The number goes anyway.

I suppose you could caption the pictures with- A light skim of the cylinder head rocker box face may be benificial to oil tightness or some such nonsense.

[danma]

These first three  pics should have gone in the first post.

 The fourth shows 2 6mm plates used to space the case halves 6mm apart.

2 slabs of 6082 were trued up .1 piece butted up to the back of the timing cover with 3mm of over hang on the inside,the other piece butted up to the first.This would leave 3mm to machine back off each half.
 
 

[danma]

 Made a couple of holes and removed some corners to reduce mass. Large studs and plates and every available clamp held it together for welding.

 A reinforcing piece was added in the timing case infront of the idler and the cam area built up on the inside to support new bushes.
 
I was expecting the distortion from welding to be the end of it,but it was not too bad at all. The top of the timing case moved in about .004 so was built up with weld and faced.

 After a bit of fettling the cases were bolted back together and cooked in a rayburn on 11 for a few hours then allowed to cool. A bit of heat treatment to de- stress them, then a bit more milling.

 Learning of John Hills ally big bore nickasil barrels I decided I definately required  a set.They can be bored to suit up to 80 mm pistons and supplied in different heights which was useful in my case.
 Pistons would be forged B44 items from Peter Quick.

 The timing side was machined for the combination bearing and the oversize drive side oversized some more for a superblend .

[danma]

 An A65  race cam [srm] will be used with 1 std A65 bush and 2 home made ones.

 The unfinished drawing I did with paint should save me some explaining.  A lot of careful setting up before I was brave enough to do the boring/reaming involved. Of course now it's been done successfully I only remember it being an easy five minute job.
  Needed to know how much to remove from the cases for a final trim. As the little ends had not been bored for the larger pins yet I made a substitute piston of the correct dimensions to make the job of measuring  easier.

 2 socket caps added front and rear at the top to hold cases together and act as dowels.

 Purchased some en16 bar to make the barrel studs. I decided on m10 as I had some nice ti flange nuts. The std A10/early A65 5/16 stud looks a bit feeble alongside the new one.It wont be the studs that break.

 Studs all done and 3 m8 socket caps threaded into the cases where there is sufficient material to do so, to  [ hopefully] help hold it together.

 A bit more milling to squeeze the ignition do-dah on and some extra oilways added.

[danma]

  Made some ptfe buttons for the gudgeon pins.These add 10 gms to each pin.  I don't know if I will use these yet but they are handy for winding the motor over without pistons for cam timing /valve gear geometry checks.

 The late lightning head went to the cyl head shop for 1mm over valves, guides and a flow. Ex spigots same as my A10 head were welded in so the old exhaust should fit.
 
 I do feel a twin plug job coming on,this should help with the lumpy high comp pistons.

 The 6 threaded ,welded in bosses in the head are to attach extra fins to, -there is a large gap between the bottom fin of the head and the top fin of the barrel. I did try 1 fin  [in the foreground of the pic] but 2 look better although these are still unfinished. This will confuse the expert fin counter types. Will be interesting to see how long they can stand big twin vibes.
 
 A pair of adjustable pushrods were made using some cut down m5 socket caps  and a clothes peg spring cut in half. [ honestly officer I was not stealing her under wear off the line, I was having the pegs away ]

  Turns out both pushrods need to be 4mm [ 1/8 and 2 or 3 blurry lines ] longer.
 A length of 4130 tubing arrived today to make a new set.

[Greybeard]

Loving this thread!

[danma]

 Got the pushrods done, the lathe was handy for pulling off /pressing on the ends with a little heat.

 Decided to polish the rockers up and found a snug fitting piece of ally holds the coach bolt concentric which makes fitting the washers easier, the washers prevent the thrust faces being polished away and there is less chance of launching the job across the workshop if you have something decent to hold.
  This is a filthy job made easier with plenty of lubricant.  At least 2-14 bottles may be required [for each rocker].

 For those unfamiliar with an A65 head it is much the same as an A10, even the same thackery washer/shim setup, which I have replaced with phoshor bronze spacers.
 Having the rocker shaft supports integral with the head and a simple lid is big improvement.
 
 Turned a stainless  oil feed adapter up for the rocker feed to match the plumbing already on the bike.

[a10 gf]

Fantastic work. Thanks for posting.

[danma]

 Playing with plasticene I found the exhaust valve misses the piston by miles , the inlet however was way too close.

 The pistons were held on an angle plate by a bar through the pin hole,the angle plate then fixed to the rotary table and a little under 2 mm removed from the flat  bits .Then used a ball nosed cutter to cut a radius on a radius.

 A recent purchase of a job lot of slitting saws and face mills  gave me a cutter which was ideal to use as a scraper to hand finish the cut outs. Wearing out some emery and a couple of layers from my finger tips cleaned it up before a final polish.

 Last pic shows the genuine plastic head gasket has already blown [5 oclock on the left pot] If I fish the missing bit out of the push rod tunnel and super glue it back  it should be ok ; as long as I anneal it of course.

[jachenbach]

I am thoroughly impressed (more like blown away) by your skills in doing this. Still, I have to ask.......why? Because you enjoy the challenge?

[danma]

Hi Jachenbach, long answer; I must apologise for giving the impression I actually know what I'm doing. I am just an old boy that knows just enough to be dangerous,with too much enthusiasm and access to machine tools with a baad [I,m going to do it anyway attitude].
 
From the start I thought this would not get very far, but at least I would try. This is by far the most difficult thing I have ever attempted and I learnt alot ,mainly not to do silly things like it again.

 Next time I'll start with billets for the cases ,barrels and head. 4 valves and ohc far more sensible.

Short answer   yes.

[edboy]

good work danma.
however would another possibility be to commission or make a set of barrels which retain the a10 flange mounting but adapt to the a65 cylinder head with some one off rockers made to suit the a10 camshaft? i m not familiar with the a65 are the dimensions far different for the larger a65 pistions in the flange area?

[danma]

Edboy,a barrel with the right size holes either end would work and seems like an easy option but the top of the cases is the bottleneck.You have to grind alot off A65 barrels to make them fit A10 cases.  The difference in the base does not look much but is enough to have a sizeable larger bore even as std. If you kept a 357 cam you would have to run a10 followers in the barrel .

 I don't know if there is any difference in the rockers other than one has balls, the other sockets.This could be overcome with end caps on the pushrods.

 I did think about making [roller] rockers but it's not that easy--casting,tons of machining.

  How I've done it does seem silly and hours of work but once the cases have been modified it really is as simple as bolting on std[ish] A65 top end. There is also the advantage of many cam grinds.
  When the cases finally let go {provided it's not too catastrophic] It can be recycled into an A65 motor.

[danma]

 Trying to measure valve spring heights I had to reconfigure the internal caliper with a bit of 2mm flat off cut. This permitted deeper penetration into inaccessable orifices but requires a tool to prod the other side of the bottom cup to prevent a seesaw effect.

 So I made another tool that looks like a hydraulic pipe fitting from more off cuts. Basically it's a nut and bolt with the bolt bored through and counter bored on the head to clear the spring top collar,and on the bottom to clear the valve guide. The nut fits loosely in the spring bottom cup.

 Screw the two together and drop over the guide ,pop the top collar and collets on and unscrew the tool. With a vernier or depth gauge measure direct.

 The piece of wood is also useful for keeping the valves on their seats  while messing around like this.

 Trial fitted the motor in the frame-- head and rocker box lid can easily be fitted over their studs. [would have been embarrassing had they not] The head probably wouldn't go on with the extra fins though so must remember to slide them on the barrel before fitting head.

 Looks like the carbs will clout the oil tank but can be sorted out.

[Butch (cb)]

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