I am looking at my options on machining my corvair/VW power plant for the bus. I have come up with a few questions and realize that I have largely been going at this alone and could use input from those who know more than me.
1) I am considering taking the money I would spend to have the p/c machined and buying a mini mill so I can do it myself. Is this foolish? Is it possible? To see what I am going to need to do, look below.

Trim the type 1 cylinder skirt, and drill new holes in the fins for the corvair head stud pattern:
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Trim piston skirts to make room for opposing rod end and bolt:
Click to view attachment

Trim center cylinder side fins down:
Click to view attachment

2) I will also need to get the block and heads bored out, the valve guides replaced and reamed to the right size, and the rods punched out and oil holes added. If anyone here is up to doing that stuff, let me know as I am looking for a less expensive alternative. But, for the cylinders and pistons, I am considering trying it myself.
Click to view attachment

Mike,
Im no machinist but I play one on tv:) I bored my 911 block for 100mm cyls on my dad's bridgeport. I own one now too;) Recently made myself some AN fuel rails for the /6. Got a pair of lathes in the basement too so Im not just talking out of my ass here:

What your talking about doing probably isn't doable on a small mini-mill. Well, maybe, but you'll kill yourself doing it. You need to be able to fixture the case halves on the table and a minimill is both too small in that direction and the z axis to be able to swap the tooling/indicating tools in & out w/o a dovetail z-column.

Trimming the cyl skirt: you mean making the whole cyl shorter or making the little step you show. Just cutting the lip down is easy on a mill. It doesn't register against anything in the case so its not critical. Making a step will require a lathe if thats what you meant.

Drilling the cyls: The fins will get tricky. Tooling looses rigidity the longer it gets. Since its ony a partial cut the endmill will want to spring away from the cyl the farther down it cuts (and/or chatter.) A LONG carbide endmill might be able to do it w/o flexing away from the cyls too bad. Luckily youre only cutting aluminum and not steel. Or, bore the upper holes (which are important to locate just right), and flip the cyl on its side and use a ball end mill to trim the fins (which can be a little sloppy as you just need to cut off "enough".)

Skirts for rod end bolts: No prob.

Trim center cylinder side fins down: No idea at all what you're talking about here.

Like I said, you can bore the block yourself (if you know the clearances reqd). Id send the heads/valves out.

Probably best to find someone who has the types of machines you need as you spend a fortune in tooling to get a mill or lathe up and running. General rule of thumb is as much as the machine itself. If you want to discuss shoot me an email or give me a ring. This stuff is prob easier over the phone. I've been exactly where you are now. First "borrowed", then bought, then upgraded...

SMD

Have someone else do it. You are not just paying for their time. You are paying for their experience. And you are paying for the ability to take it back and have them fix it if they screw it up.

Where we live is over-populated with machinists. I can direct you to some of the guys that I have used around York. They have all been speedy, and way less spendy then I would have guessed.

Zach

I wouldnt attempt boring the block of heads on a mini mill. I was looking to see if anyone would do it. The stuff I am thinking of tackling is the piston and cylinder stuff, only. The rods, block and heads are cheap enough to get done local or at a friends, but the one guy I know wants $500 to do the p/c and I could buy a mill and do it myself, I think.

I am supposedly hearing back by tomorrow on a local shop that a friend of mine knows. I just ordered the p/c as I figured that having them in hand would be a nice start.

I like your synopsis on the hows, Steven. I'll have to call ya and chat this weekend, maybe.

Oh ya, the cylinders are TI VW so are cast iron and not aluminum. Luckily, it looks like they tend to drill the holes in sections according to what I am seeing in the picture.

The cylinder skirts only need to be trimmed down a little as in the pic. It seems fairly straigh forward and I have many core TIV p/c to practice on first

John Barnes is an old friend of my dads who still does the corvair stuff.
you might wanna call him.
http://www.corvairkid.com/190cid_01.htm

Found Johns contact and shot him an email. The going rate for everything is $1600 from all of the vendors I know: SC performance, Stinger motorsports, etc. I am trying to see if it can be done for less, just because I can


Here is the little monster I am considering:
http://grizzly.com/products/G8689

Zach,
The fun is in doing it yourself. Because you can. This stuff usually isn't rocket science. If you know: remove "x" amt from the cyl skirts, anyone can do it. If its a trade secret then its is better left to the pros.

Mike,
Oh man, FORGET it. You won't get anything done on that toy (well, maybe the pistons). Notice the 11.5" max Z. An endmill + holder is at least 3" leaving you 8.5". A drill chuck+drill eats up even more. A boring head is WAY more. Then you have to worry about fixturing. If you can clamp straight to the table its less of a problem, but a vice eats into that. Are the pistojns flat topped? If not, you're going to have to put something under them. Very quickly you can see the difficulty in machining even something as small as a piston. Cylinders are out of the question.

Bigger machines like:
http://www.grizzly.com/products/Mill-Drill...chine-25/G1005Z
turn up on CL for less than the small one you're looking at. It doesn't have a dovetail column but at least its bigger (and possibly? more rigid.)

The big downside of a round column is that if you have to change tools w/ varying heights you might have to move the column. That 'loses' your X/Y location. Say you want to drill and then mill an small amount - all w/ relative precision. drill+chuck stick out 6+". End mill is 3". = 3" difference. The 3-5/8" spindle travel means you only can mill 5/8" deep w/o moving the Z. Once you move the Z, it will also rotate slightly side to side, so you completely have to re-indicate off edges to rezero the dials. If you're patient you can do the job, but it'd make me want to blow my head off. While its a limitation, its far less of one than the little machine. Plus, you can bolt a vice to the table and leave it there. Once aligned and tightened down, you are GUARANTEED that anything you put in it be square w/o dicking around for 10-20mins EVERYTIME trying to to bolt something to the table.

The holes in the fins are not needing to be precise, luckily. The pistons are flat topped, and I did intend to clamp directly to the table for milling the cylinder skirts flat.

Maybe I need to come over to your basement

Heres the minimum "really usefull" looking mill:
http://newlondon.craigslist.org/tls/660063039.html
http://www.grizzly.com/products/Vertical-Mill/G3102
Benchtop sized w/ dovetail knee.

Though $1200 is still a bit much IMO. Thats getting close to what a used (slightly worn) BP will go for. But, not everyones basement/garage/living room?? has space for one of those.

Yikes, ya big and far. If it were closer I may be interested. I could do my boring on that one, no?

My latest thoughts,

The holes in the cylinders can be done with a drill press, no? (carefully)

I can use a belt sander to trim the skirt, no?

I can convert my mini lathe into a horizontal mill and do the pistons in it and not have to buy a mill, no?

I agree with whoever said this first (too lazy to look who it was). Getting a rigid tool setup is key. The biggest limitation of a small machine is not always travel and almost never horsepower. It's usually being sturdy enough to handle a job. If your setup is flexing all over the place, you won't get any precision and you'll drive yourself nuts! Also, given that you're willing to do this now, I would think that you'll want to machine stuff in the future. That being said I'd look at larger, used machines and get the job done that way. I think the one that smdubovsky posted would be sufficient, but barely. Try to go as big as you can afford.
As far as cost goes, it never ends with the machine. You need cutters, holders, indicators, inspection equipment, and a way to hold your work down(i.e., a vise and/or a set of clamps). It'll help if you have someone local that you can borrow some of these things from.
Now if that didn't scare you off, let's get down to business. Given that the cylinders don't locate off of the studs, drilling the holes in the fins will be no problem. I'd say drill through the top portion that are complete holes, flip the cylinders, and mill out the partial holes on the bottom. Sorry smdubovsky, but I wouldn't use a ball nosed endmill for that job. I think that would deflect more. I'd recommend using a flat nosed, two flute endmill and just plunge it slowly.
Cutting the cylinders down on a mill would be a cake walk if you don't need high precision. Just clamp it down and hack it off. Trimming the side fins is similarly easy given the low precision necessary. I'd just side mill it, but it would need to be done in two passes; top and bottom. No cutter that I've used is long enough to do that in one shot.
I'm not sure what you mean with the skirts, but it sounds like you just want to cut them down. If this is the case, it's similar to the two previous operations, but I'd try to do this to some level of precision to maintain a certain level of balance in the rotating assembly. +/- .001 ought to do.
All of the afore mentioned jobs would be cake on a machine like the one that smdubovsky recommended. Boring the block and heads would be more difficult, but not impossible in my opinion. The key with that is taking a good long time setting it up and indicating it in, as high precision is necessary. I wouldn't do with less than a test indicator with .0005" resolution, but .0001" is preferred. If you do decide to tackle those jobs, you will absolutely have to invest in a set of parallel clamps. Something like that can't be held in a vise. I have ideas on how to set up those jobs if you get that far.... never done a block, but I just finished my T4 heads.
The valve guides would be easy to indicate and ream, but I don't know how you'd press them in just because I've never done it. I don't quite understand what you need done with the rods, so I won't go there right now. PM me if you need any further advice. Sounds like you've got some good local talent to help you out there too. Make good use of it, but make sure they don't take over the job. Make sure you can do it yourself next time. Good luck.
Mark D.

Oi... New questions by the time I posted.. Haha. The holes in the fins can be done with a drill press, but DEFINITELY use an endmill on the partial holes, and definitely don't try to put any side load on the drill press (i.e. milling). Just plunge in and out, and that's it.
Belt sander, I don't know. I'd be concerned about breaking fins.
The mini lathe may be used for that piston skirt job, but I don't know how precisely. As I said before, rigid tool setup is everything, and taking an interrupted cut... You'd have to chuck the piston with some brass shim stock (to maintain the finish) and indicate the skirt to make sure it's perpendicular to the spindle axis. Like I said before, +/- .001 is what I'd shoot for on that job, and that includes runnout. I'd also take very minimal depth cuts, as that small tool post will flex a lot under interrupted cuts, and even spring cut once I got down towards the finish dimension.... Oh, I just reread what you said about using the lathe as a mill.... No, I don't think that would work, but you could just chuck the piston up and face the skirts, as I just described.
Yes, it can be done.
Mark D.

It'd be hard as hell to drill holes w/ a press. Since the holes are connected to the old ones, a drill is going to try like hell to move over to that hole. Surely you've tried something like that before. Endmills don't have that problem. Maybe you could drill a smaller hole that doesn't break though, and then use a piloted cutter to open it up?

Yes, you actually could use a belt sander even if it is a caveman approach;) Its going to take a while too. How big is your mini-lathe? 7x10? Grab it w/ the inside jaws (pad w/ brass strips) and part off the end. Its just more classy than a belt sander;)

The little mill attachments for a lathe are for REALLY small parts. Though, if you bought a simple iron webbed angle plate (<$20 enco) you might be able to use it as a horiz drill press. Clamp the plate to the cross slide, cylinder to the plate, and put an endmill in the lathe chuck. Though, might be usefull to find the appropriate sized collet to hold the endmill for extra rigidity.

You might even be able to do the pistons that way. You'll have more difficulty setting up the Z dimension w/o fine adjustment, but you could just clamp them to the angle plate at the right height (clamp a fixture block to make repetition easy?). Use the cross for the cutting. Only the cut near the center is critical location wise, all the others are just removing material closer to the edge as you move and clamp the piston further and further up the plate. Make sense?

Heck, you could even do the pistons w/ a die grinder + carbide bur. You're going to need to do something anyway to get them back into balance even if you use a mill.

If you get creative anythings possibile w/ few tools. The right tools just make the job easier.

EXACTLY!
Mark D.

Mark D,
What I meant w/ the ball end was: plunge w/ any endmill to the depth you can easily reach (at least though the first ~4 'complete' fins), then flip the cyl on its side and use a ball end to machine out the channel down the side. No need to plunge a LONG carbide endmill the whole distance then & no worries about stiffness.

Ah... Sorry for the misunderstanding. That'd work too.
Mark D.

In a word, No, have someone else do it.

I have the Harbor Frieght version of that mill. I'm not a machinist, but I use it to make tooling and what not for my fiber optic test fixtures.

I CNC'd mine. http://www.youtube.com/watch?v=6nKeic6XI4Y

Learning to mill is not exactly a Bolt it down and cut operation. I've got almost $5,000 into that silly little thing. You will spend more on tooling and fixtures than you will on the machine as someone else has said.

Biggest issue is the Travel. 9.5" in X is ok for what I do, but the 4" in Y kills me. Lots of indexing and moving the part around. The 8" of Z is ok for working with flat stock, but when you add a vice or a tall part. It start getting close with things like Drill Bits.

Just my thoughts.

Smitty

You guys have what I am thinking about down, I think. Here is a pic. Click to view attachment

I could fit the pistons in I think.

Here is the site the pic came from. It is a great reference
http://www.varmintal.com/alath.htm