Engine rebuild: part 1.

The engine has been rebuilt! Here is part 1.

here we see the crankshaft, apparently all ready to go, yet hiding a sneaky surprise ready to bite us in the ass before long.

A new roller bearing on the drive side...

...new standard size big end shells, wrapped in wonderful oily parchment.

Testing the oil passage on the connecting rod.

But what's this? just as he started tightening the second connecting rod onto the crankshaft, Peppe noticed it wasn't turning freely.
Off comes the connecting rod, the new big end shells are inspected and we see a hairline scoring that wasn't there before. Magnifying glass at hand, Peppe discovers a small nick on the main journal, which definitely wasn't there before we handed the parts to the machine shop. Who knows what happened, but you'd expect better from a machine shop, right?

The imperfection is gently massaged away with a small file and some very fine sandpaper...

...the torque wrench is set carefully to 22 ft lbs

and both connecting rods are in place correctly.

The new timing-side bush.

ALL this scattered ground zero of parts will soon be a compact, purposeful engine.

The back of the cylinder head. Peppe did some serious cleaning on the inlet manifold, which I had forgotten about when I cleaned the crankcases. You'll see it in part 2 of the rebuild.

The camshaft is back with a new thrust washer.

I cleaned the cylinder barrel and found the paint to be in better condition than I remembered.
Peppe scraped away some surface rust here and there with an exacto knife and I gave it a couple of coats of heat-resistant paint. So far it looks pretty good!

Just as we were getting ready to put the two halves back together and of course *after* applying the gasket cement, we noticed this other surprise, again courtesy of the ham-fisted, dim-witted twit at the machine shop:

I know for a fact that this used to be intact. This is a pretty major inconvenience and it did cost us quite a bit of time. Luckily the man is handy with a lathe...

...and a set of dies.

Going mano a mano with a piece of round stock to turn it into a new stud.

Pressure testing the sump scavenge passage.

Grabbing the bunny by the ears.

Here we go:

Great stuff.

Timing gears back in place.

Ready to dish out some road-burning mayhem, watch out!

Here's a new paper gasket for the oil pump. It's from a complete NOS set I bought years ago.

Oil pump and worm drive back in place.

This is the oil pressure release valve:

doesn't it look like some sort of apparatus from a Jules Verne novel?

Back in place.

Now for the gearbox.

Score!

I scored a couple of mark-ones, two weekends ago. Not a pair, a couple. Because one is a 928, the other a 930. They had been left to rot in a basement somewhere and they would probably have become archaeological artefacts if I hadn't picked them up. I tend to look at things like these more as a source of spares than something you would clean up and use - though you certainly could do that too. Even without these, I would be all set for my BSA. I have a great Mk1 with all sorts of trick parts, yet to be unveiled. This is icing on the cake. I opened them up and realised they hadn't been taken apart or messed with too much. The floats are good and that in and of itself is worth the trouble. A few float bowl screws, you can *never* have too many of those, trust me. The mounting flange on the 928 is visibly warped and that's the end of that carb. No point trying to fix it really. Both float bowls are useable: they're the early type (which I prefer, to be honest) without the additional plug that lets you access the main jet without having to remove the whole float bowl (and banjo bolt). I prefer those because they allow more room to access the banjo bolt, and because they don't offer a potential source of leakage, from the extra plug. They carried the original nylon needle valves, always a dead giveaway that a carb hasn't been molested.
More on these bits soon...

Machining: done.

Right, the cylinder barrel and the crankcases are back from the machine shop, we'll be double checking the tolerances because you can never trust anyone too much. And as it turns out, you really can't: they stripped a thread on one of the crankcases' studs AND they fudged up one of the main journals on the crankshaft! More on that in the next few days.

I love the look of new pistons. These aren't sophisticated, by any means, but they are honest, heavy duty bits of kit that will get the job done. We've gone oversize one here, that way I know everything is tight and true, no mystery smoke popping up 4 months down the line...