BMW V8 dry sump from billet

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AdeV:
Right, where were we?

OK - the block is now on the mill, and dialled in true. First job, then, is to measure the engine up. I've decided to start with the fixing holes, as they're easy:

There's 28 of them all told - 10 per side and 4 each on the front & end. I have to switch to metric now, this being a German engine. I can use the fact that they'd probably not use TOO many odd measures. So having located the first hole at 48mm in, the second at 57.5mm further along :scratch: I wasn't wrong, though, it really was 57.5mm...

So, the moment of truth.... I've indicated in the corner, added 50% of the excess space (about 4mm all round), used the DRO to navigate to the first hole position, and am about to drill...

Note the real-life crap-o-cad, complete with co-ordinate readout :D Although I'm not relying on the layout drawn on the wax itself, it's gratifying to note that the hole is within the boundary of the splodge I drew on the the wax, through the gasket.

So, a little later on:

All holes (even the ones under the clamps which, you may have noted have moved (doh!)... I had to move the left-hand one again before I finished for the day...

Now, look back at the bottom of engine picture: There's 9 holes near the rim of the sump - 4 at the top, 5 on the bottom. These are the oil drains from the heads, and in use have oil pouring out of them (apparently). In the original sump, there were two compartments; the head oil went to the bottom compartment, through those holes; the oil underneath the con-rods went a different way. Although all of the oil in this sump is heading to the same place, I'll try to keep them as separate as possible. So; I decided to cut the start of a channel into the sump, at each hole. This will help guide the oil into the drains, without letting it all splash about under the con-rods.

So, using the nearest end mill I have to 18mm (a 3/4"! :clap:), I plunged 18mm at each place. The sump gasket could then be fitted to the block to check for alignment and location of the holes. And, I'm well chuffed to say, they're all in the right place!

You'll notice I've also milled out a shallow pocket in the centre; this is where the main sump will slope down towards the drain holes.

So, there you go. Finally, I'm making engineering swarf, instead of just parting off swarf... And it feels good! :headbang:

Tomorrow: Mostly measuring and planning I suspect. I need to make a jig so I can tell how far out of the bottom of the engine the con-rods protrude at their lowest point, to make absolutely sure I build enough clearance in (but, at the same time, I want as little clearance as possible so I can keep the profile of the sump as low as possible; and, hence, the weight).

AdeV:
OK, some more progress today.... First job was to work out the clearances for the conrods. So, using a wax offcut, I roughly milled out a segment - with many trial fits to the engine. Eventually, the hole was big enough:

This was then measured, and a second piece marked out & cut with a bandsaw, just to verify that my measurements were, in fact, sound:

That white tape is holding the wax together; it broke at a boundary between two pours... So far, the main block is behaving itself very well, which is a relief.

So.. clearances sorted out, it was time to get milling. The angle plate (which is needed later) is mounted & squared up first, then the block is mounted & squared on the angle plate. Thus:

In the pic, I'm about to locate my reference point (the top right-hand corner, as you look at the picture), from which all subsequent measurements and co-ordinates are taken. So, about an hour later (I was being cautious....):

They're milled 25mm deep, 75mm wide as required. The bits in between each pocket are where the bearing journals live, and will be left there for strength. So now it's time to mill out the first angled bit. Thus, it's time to brush off my old Trig knowledge, and get head scratching :scratch: :scratch: :scratch:

Most of you will probably be immediately familiar with all of that. The only bit I'll explain (just in case, if by the remotest chance, my old school Maths teacher ever sees this: Thanks Mr Parry!) is SOHCAHTOA (pronounced "soccah toe ah"). It means, simply: Sine=Opposite over Hypotenuse, Cosine = Adjacent over Hypotenuse, Tangent = Opposite over Adjacent; I've always found it to be a dead handy aide memoire when messing around with triangles.

So, on with the show. 33.7 degrees the doctor called for, so we set up the angle plate:

The small spanner there is used to loosen & tighten the angle plate bolts. Did I mention I'm doing this in miniature? That spanner is just 4" long... :lol:

So, after a little while:

The actual cutting operation was done largely by look & feel; when I thought the remaining lip looked "about right", I stopped cutting. The coordinates have been noted, so when I come to do the real aluminium sump, I should just be able to crack right on into it, without worrying about where to start & stop cuts.

Last job for today was to flip the piece over and cut the other angle. About 40 minutes of the next hour were spent setting up:

* Reset angle plate to flat
* Turn piece around
* Dial in
* Find reference point & reset DRO
* Set angle
After that, the cut went on nice & easy. Because I used the same reference point, all my X-axis numbers were the same (with the sign reversed; so positive instead of negative); the Y-axis was also mirrored, but somewhat differently... In fact, I ended up with slightly different offsets; but I think I got the first ones in slightly the wrong place, as there's more of a lip on the first cuts compared to the second.

So, as it stands now:

Next job: Figure out where the channels for each main oil drain (the holes cut yesterday) are going to go, and how deep they need to go to pick up the main oil channels. And, speaking of which, the time draws ever closer when I'm going to have to break out that big drill.......

Watch this space :dremel:

CrewCab:
Looking good Ade :thumbup: .......... the way it's going you could have gone straight to the ali and dispensed with the wax ......... though perhaps that may change when you break out the big drill :dremel: ............. good luck and keep posting :beer:

CC

Dean W:
Watching.. Watching.

Brass_Machine:
Pretty cool. Nice skills too!

Eric

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