34 - Into the Guts

Right! Well, all the 'hard' stuff requiring special tools is... done. I'm now at the phase where I should just be able to take out all of the major rotating & reciprocating assemblies including the camshaft, pistons, and crankshaft. Basically, the guts of the engine. 

I have read many dire imprecations about this, chiefly around keeping things organized and clean. So, I did my best. 

First to come out is the skew gear. This was removed according to the overhaul manual. 

Then came the camshaft itself: 

First you have to remove the camshaft retainer plate, and it basically comes right out. One has to be quite gentle when doing so, because the fit, of course, against the cam bearing races is tight. 

The camshaft looks... okay! I haven't mic'ed it yet, as I don't have the precision micrometer to do this, but it does look to be alright. The surfaces aren't too worn and there are no obvious problems that I can see at first inspection. Hopefully it's reuseable?

Well, since that went so well, let's move on to something bigger: the pistons!

First problem: finding a socket that will work on the nuts. Irritatingly, I only have 6-point metric sockets, and these require 12-point sockets. For reference, a 5/16th Whitworth socket *does* work on the big end bearing caps...

I don't know how these engines were assembled from the factory. Are the numbers on the big end caps supposed to go the same way as the main bearing caps? 

Who knows. 

The process of pulling the pistons out is fairly simple and it works exactly like you see it done in the youtube videos. Not much to it: just use the handle end of a hammer to tap each piston out, catch it (obviously) and lay all the parts out in order. 

Which is what I did:

I made a blue shop towel 'blanket' for the camshaft, as you can see above. Hey, y'all told me to keep things clean!

Anyway, the pistons are out. And there is some wear, as you can see in the photo above, and some carbon buildup on the piston faces. But, I couldn't see any numbers stamped in them so I suspect these could be the original pistons. This would be good news, I think, in case the cylinders need to be rebored. At any rate, we will inspect these in more detail later. Or more likely, we'll send everything off to the machine shop for measurement. Meanwhile I have new bearings already and will order the correct rings once the pistons & gaps are measured.

Right! On to the crankshaft. First remove the bearing caps (breaker bar recommended) and, once done, will lift right out:

Again, here I've been careful to put things in order so they can be reassembled and inspected. 

But, at first glance, it appears to be serviceable. The two areas I wanted to look at most were the front and rear sealing surfaces: if these are worn, the crank seals will fail and we'll get more of what we had in a previous post: a giant, oily mess. I'm keen to avoid this as much as possible. Running my fingers over the surfaces, I can't feel any grooves; in the picture above, you can see the worn area of the crankshaft where the rear main seal has run over the years. It doesn't seem to be nicked, pitted, or otherwise unusuable. 

The main bearing surfaces look good, and from the naked eye (and to the touch) the big end bearing surfaces look okay as well. Again, here's hoping that we have a good crankshaft, as it's an expensive piece to replace. 

Look, ma! Empty holes! 

The cylinder bores look decent, but again, cleaning and precision measurement will be necessary. As the overhaul manual states, these will need to be checked for ovality, taper, and other wear indicators. For now, a quick wipe down to clean them up a smidge will do. 

And here we have it: a stripped engine block. 

The only things left to do are remove any bolts -- you can see three visible here of course -- then drive out the core plugs in preparation for machining work. 

Anyone know why a previous owner squeezed some silicone into the two holes on either side of the vacuum pump mounting flange?

It's nice to end 2024 with some progress after such a long break. Rebuilding the engine is arguably the biggest single component of the whole project, excepting maybe bodywork. So it feels pretty good to have a look at this engine and have it ready for its next major stage.