OK, technically the cylinder heads didn't come "back" from the machine shop, because they're not the ones we took over there. Once the guy who runs the shop (let's call him Bernie, on account of that's his name) got our old ones apart, he found that the valve guides were worn out of tolerance and would have to be replaced, and that they're just a year or two too old to have the hardened valve seats modern fuels require.

Unfortunately, they're also a revision in which the existing seats aren't inserts, they're part of the casting, which makes retrofitting them with the hardened ones a real pain in the butt. All told, we were looking at about $1,200 to get them rebuilt--and in the process of machining the castings to take the new valve seats, there's a real chance of accidentally cutting into the cooling jacket, at which point you have just made a boat anchor.

So, Dad did a deal with Bernie for this other set of heads, which he built for someone a couple years ago and then ended up going with something else. They're a slightly newer casting and are fitted out with hardened seats, new guides and valves, and slightly stiffer valve springs than stock. They weren't cheap, but they were also not 1,200 bucks with 16 chances for failure.* We traded him the old heads as part exchange. He can stick them on a shelf (he has many shelves full of SBC cylinder heads, I've seen them) and someday down the road, when someone wants to build an engine they're suitable for, there they'll be.

The crankshaft and connecting rods we sent over have been cleaned up, checked over, and polished. This fills in one of the last pieces of information we needed to start the build, namely by how much those bearing journals had to be ground. Turns out the mains are now .0020 under, and the connecting rod journals are .0010 under. With that in hand, we can order the right size bearings, and once those arrive, I can start to actually build the dang engine.

Everything's on order now, and should be arriving Thursday or Friday. We have therefore scheduled the first of the actual build sessions for Friday afternoon. So that's exciting...

--G.

* I'm not trying to knock Bernie's skill here, the man clearly knows what he's doing. But it's a delicate operation you have to repeat 16 times in a row, and, you know, shit happens.
-><-
Benjamin D. Hutchins, Co-Founder, Editor-in-Chief, & Forum Mod
Eyrie Productions, Unlimited http://www.eyrie-productions.com/
zgryphon at that email service Google has
Ceterum censeo Carthaginem esse delendam.

Amusingly, one of the boats that is on my consideration list (I am slowly but surely losing my will save against buying a sailboat) has a number of little things wrong with it, including missing an anchor (and chain etc)

--
-Pasha
"Don't change the subject"
"Too slow, already did."

--G.
-><-
Benjamin D. Hutchins, Co-Founder, Editor-in-Chief, & Forum Mod
Eyrie Productions, Unlimited http://www.eyrie-productions.com/
zgryphon at that email service Google has
Ceterum censeo Carthaginem esse delendam.

First, we had to clean up the crankshaft. This had been cleaned by our main machine shop prior to being sent by them to another machine shop that had the correct tooling to refurbish it, but not again after it came back.

To this end, my father's had a parts washer for literally decades that he's never gotten around to using. He bought it shortly after moving into the house he just moved out of, and the whole time he lived there it sat in the garage without ever being used.

A parts washer of this vintage was originally meant to be used with some volatile petroleum fuel as the working solvent (usually kerosene, though some people use diesel fuel and some particularly deranged cowboys even make a habit of using gasoline), but we decided to go with something a little less crazy and picked up some water-based cleaner/degreaser fluid at [big box store]. This took an inordinate amount of time, because we didn't think to measure the reservoir beforehand to see how much fluid we needed, and the first time around we didn't have enough to cover the pump pickup, so we had to go back to the same store and buy the rest of their stock. So that killed an hour or so more than we were expecting, but in the end, we had a working parts washer for around 40 bucks, which is pretty good.

The cleaning fluid we went with is called Purple Power--a lot of these things, riffing on Simple Green, are named after whatever color they're dyed, and this one is no exception.

It is, indeed, purple.

Our main concern here was the oil passages inside the crankshaft. This is the way the main bearings and connecting rod bearings in these engines are lubricated--the engine's oil pump forces oil into passages within the shaft itself, starting at the back (on the left in this photo) and up to the front. Along the way it comes out of those holes in the bearing journals, for which there are corresponding holes in the bearings themselves, and lubricates all the various friction points in the rotating assembly. Those passages can get blocked by debris, which will then starve one or more bearings of oil, which you don't want.

The cleaning process involved using the parts washer, which develops fairly high pressure, to force fluid into the holes, then watching where it comes out. They're all connected together inside the shaft, but since liquids like to follow the path of least resistance, it usually comes out of the next hole along--for instance, fluid driven into the second hole you can see in that second connecting rod journal comes out of the hole in the main bearing journal ahead of it (to its right in this pic), and so on. (In a working engine, the whole system is pressurized and it comes out of all the holes at once, though even then, the front main bearing is most susceptible to oil starvation, since it's at the end of the line.)

Following the bath, we then moved the crank back to the workbench and went over it with an aerosol can of parts cleaner; this is higher-pressure than the washer and dries without leaving residue, so that step is sort of a cleanup-from-the-cleanup, making sure there's no cleaning fluid left in there to contaminate the oil later on. I didn't get any photos of this because I was too busy doing it.

At that point, at long last, actual assembly could begin. First to go back are some of the smallest parts in the system: the crankshaft keys.

These two little metal biscuits will eventually help to locate the crank gear. After checking to make sure neither they nor the slots they go in had any burrs that could affect the fit, I carefully tapped them into place with a punch (not the big brass one shown; a steel one about the same diameter as the width of the keys) and made sure they were as horizontal as I could get them.

Job done!

With that taken care of, the next step was to install the new main bearings in the block and main bearing caps.

The block came back from the machine shop with the caps installed and torqued down to the correct levels, which was done to make sure the holes were properly round and concentric with the structure under the proper tension. Therefore, the first order of business was to bust them all back off again and set them aside out of the way.

The caps are numbered and have an arrow on them indicating which way is forward, to make putting them back on in the right place as easy as possible. Of course, with the frontmost and rearmost ones, it's pretty obvious anyway, since they're unique. The rear main bearing is different from the others in more ways than that, since it's the one that has the thrust bearing and the rear main oil seal in it as well.

I failed to get photos of the bearing shells or the seal themselves, since by the time I was ready to install them, my fingers were covered in assembly lubricant and I didn't want to touch my phone. So here is a stock photo of such a bearing set I swiped from Summit Racing's website:

The larger bearing shells on the left are for the rear main bearing. Notice how they wrap over the journal rather than lying within it like the other ones do. That coppery-looking surface on the outer face is the thrust bearing, where the crank makes fore-and-aft contact with the block. This handles the axial loads that are caused by the way modern (i.e., post-World War II, more or less) transmissions work. The others don't need that because they don't handle any such loads; they're only concerned with rotation. The ones with the grooves go in the block (note the oiling holes), while the smooth ones go in the caps. The little nibs at the ends are keyed so they only go in one way (you can see the corresponding keyways in the photo of the block with the caps off).

Once the bearings and the two halves of the neoprene rear main seal (which goes in the groove you can see in the rear main bearing area behind the bearing itself) were in place came the moment of truth: installation of the crank itself, followed by the bearing caps. These have to be tapped into position, since they have a slight interference fit with cutouts in the block to help locate them, and then the bolts must be installed and torqued down. In this model SBC V8, with the four-bolt main bearing caps, the longer middle bolts are torqued to 75 lb-ft, and the shorter outer ones to 65. As far as the order goes, in this type of engine, you start with the rear main bearing, then the front one, then the center one, and then it doesn't matter what order you do the remaining two in. After each one, give the engine a spin to make sure it's still turning freely. Even with all the bearing torqued down, it should turn easily if you've been sufficiently liberal with the assembly lube.

And there we have it: the crank is fully installed, and the bearing caps are all torqued to spec. (Note the little dab of red at the very back of the rear main cap, at the very end on the right side, closest to the engine stand. That's high-temperature sealer that the manual I'm using suggested adding to supplement the seal, which is right under that part of the cap.)

I was hoping to get a little closer to a complete short block this session, but the rigmarole with the cleaning fluid took up too much time. Next session, it'll be time to install the pistons, rings, and connecting rod caps. That will probably take up the whole day, since each piston operation has to be done eight times, but we'll see. Might have time to get the camshaft in there and the crank gear installed as well.

I'm tired, but also pretty pleased. I did most of the work on this myself, and it didn't come out too bad for the work of a man who's lost most of the feeling in seven out of ten fingertips.

--G.
-><-
Benjamin D. Hutchins, Co-Founder, Editor-in-Chief, & Forum Mod
Eyrie Productions, Unlimited http://www.eyrie-productions.com/
zgryphon at that email service Google has
Ceterum censeo Carthaginem esse delendam.