1946 bitsa project

[Simon.Gardiner]

Looks to be coming on nicely, Shawn.
That clutch shouldn't be heavy - I've never had a problem with a 'standard' cable or my preferred routing of along the top tube and down behind the battery carrier, but I do spend time making sure the operating mechanism is in good adjustment (and condition).

SG

[SEDoan]

Thank you Simon. I'm thinking the heavy clutch is due to stiff springs. I've got 2 old sets, one longer than the other, but both have approx. 0.080" wire diameter. Planning to consult wth Geoff the gearbox guru.

[SEDoan]

Finally got the head assembled and bolted on. Used the stronger valve springs, but it now has a single lobe cam and the HS cambox oiling mod so should be durable - he said hopefully... Interestingly I double checked the fit between the head and cylinder spigot and found that installation of the valve seat had raised the edge of the recess slightly.

Assembled a dynamo cush drive on the mag and found good fitting bolts and washers. The rubber seal between the timing case and the mag was slightly too thick to get the bolts started (perhaps because I'd also added a thin gasket over the armature spindle as suggested in the Waller book) so cut a new seal from some thinner neoprene sheet. Also found that the nut that retains the dynamo drive spring was slightly too thick and interfered with the mag drive sprocket. And then my brand new chain had 1 too many links... How does this happen?

Fitting the mag and timing gears took WAY MORE time that it should have, but shows how complicated it can be to assemble a bunch of parts that have never been together before.

But then I got to install a brand new Hawker oil pump from Draganfly.
The pump drive peg seemed to have been previously welded or something so needed some dressing with a fine file to fit the alloy drive block, but now it seems very happy.

[KenS]

Coming along nicely!

[Vincent.vanGinneke]

Hello Shawn, can you give me the diameters of the plungers please? thanks

[SEDoan]

Hello Shawn, can you give me the diameters of the plungers please? thanks

It looks like feed plunger is 8mm and the return 10mm. I would have said the feed was 5/16", but the return is a little larger than 3/8".

[SEDoan]

Rocker box parts were selected and cleaned up - the bottom edge of the rocker boxes surfaced, inspection cap threads confirmed, bolt threads cleaned up. Caps are both long thread versions, but one seems much more recent than the other. Will be sealed with rubber o-rings.

Once the rocker boxes were assembled I realized that, ideally, longer pushrods were required by the decompressor plate. I had ordered some 0.028" wall 4130 tubing and harvested the ends from a set of short (350?) pushrods to make up 2 new pushrods. I also had some 0.050" wall tubing and wondered how weight it would add to a pushrod. And finally I had bought new Draganfly pushrods and was surprised how heavy they were. Here are the results (all VH length):
Aluminum pushrod = 60g
steel using new 0.028' wall tubing = 69g (about 1/8" longer than stock)
stock steel VH = two were about 73g and two were about 82g. I can't see a reason for the difference.
steel using new 0.050" wall 4130 tubing = 105g (I didn't actually make this pushrod so it is not in the picture)
new Draganfly steel pushrods = 122g
Picture from top: new 0.028" pushrod, new Draganfly pushrod, stock steel pushrod 82g and Aluminum pushrod.

Silly note about making the first pushrod. I used a press pushing against a block of wood to install the top, but needed more clearance for the bottom end and changed the wood for a steel plate. Push, push, push, bent! Presses have no feel.
Also, the intake pushrod seemed tight in the intake cam follower - it would not rotate easily. The cam follower was already built into the engine so I checked with two other sets of single lobe cam followers and all seemed tight on the intake follower (but OK on the exhaust follower). This included used followers and a new set from the club. I polished the bottom ball so it would rotate freely in the intake follower.

I've struggled with rocker box oil leaks at the decompressor and the feed lines so wanted to make everything as good as possible.
The taper seat on the decompressor spindle was lapped in and a new cork gasket cut for the shaft followed by shims to give it good tension.
An old copper sealing ring was annealed and then the threads slathered with RTV silicone and threaded in. Some beat up HS rocker feed banjos were sweatted apart, cleaned and re-soldered with new copper tubing. The old tubing had an ID of about 3/32", but the new had 1/8" ID. The banjos themselves had a small inlet of about 5/64" which I drilled out to 3/32" which is the diameter of the feed hole in the rocker shaft. (I was reluctant to go larger for fear that the running engine would fill with oil!) I then soldered it all together but testing it revealed that the exhaust rocker banjo was blocked by a blob of solder! Check everything!
I had aluminum rocker box gaskets from Draganfly. These had leaked the last time I used them, but this time I surfaced both the head and rocker boxes (and gaskets), and used RTV silicone to glue them to the boxes. The box+gasket assembly was then sealed to the head using anaerobic sealer. (In general I've had good luck sealing joints by using RTV silicone to glue the gasket to the removable cover or box and using grease or anaerobic sealer on the remaining joint.)
Next time I use a decompressor plate I might use stock pushrods and glue the rockerboxes directly to the heads without gaskets...

[nevhunter]

Normally you would use the Aluminium pushrod only with All Alloy motors to retain a more stable tappet clearance. I've never used a cork seal .There's a taper on the large dia that the dished springs keep loaded (In theory). A suitable sized High temp "O" ring before you put the arm on might work better Nev

[Vincent.vanGinneke]

Thanks for the sizes, I'll compare them with the Morgo (Triumph) pump I converted many years ago but never used.
What seemed a good idea was in fact a overkill to use a pump meant for a plain bearing in a ball/roller bearing engine.
It's a nice paperweight
To much flow is not good, although a bit more then a original pump would be o.k. I guess.
Ariel did upgrade the pump over the years but never excessiv.

Using a O ring on the rockerbox caps.... I would use a good fibre washer instead.
O rings tend to wriggle out when tightened up.
another good item to use is the WNG rockerbox clips, is anyone making these ?

[Vincent.vanGinneke]

Pumps :

Ariel 1952 - supply : 6.35 mm return : 9.52 mm
Hawker - supply : 8 mm return : 10 mm
Morgo Triumph/Ariel - supply : 10.6 mm return : 12.4 mm