SOT: Need machinist input on project idea Options

[Dr Evil]

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:



Trim piston skirts to make room for opposing rod end and bolt:


Trim center cylinder side fins down:


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.

[smdubovsky]

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 (IMG:style_emoticons/default/rolleyes.gif) 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