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mxracer Samba Member
Joined: April 09, 2011 Posts: 568 Location: NC
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Posted: Thu Feb 23, 2012 6:38 pm Post subject: Almost there.... |
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End of last year I built an engine for my square, after a shop "helping" me f'ed it up.
In the process I found that there are only 1 or 2 people in my area that do VW machine work. If you have a V8 you can throw a rock and hit one, but say Volkswagen and they look at you like "what?".
I've had a lathe and a small mill for a while now and always wanted and "excuse" to buy a real mill. Well this was it. I decided that I would tool up and at the very least be able to do my own engine machine work. I don't plan on making it a full time thing but plans are to end up doing machine work on the side for friends and a couple local shops.
Thanks to people like Ray Vallero and John at Costa Mesa for posting pics and videos of VW engine machining processes that gave me ideas and pointed me in the right direction.
Tonight I finished the engine case fixture and had to at least make a cut. I centered up one hole and did a quick deck cut just to see. The tools were made for me by a tool and die maker in WI, thanks Randy. Although I doubt he's here.
Anyway thought I'd share my excitement in getting things setup. Next on the list is an angle plate for head work. Only down side tonight was that the tapping head I bought is too big (long) and I'll have to either straight power tap, get a riser or get another smaller tapping head for installing case savers.
Here's a couple pics of the setup, fixture and my first practice cut on an old case 1/2. (Thanks to Wayne in Fallston for the old cases and heads to practice on.)
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mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
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Posted: Thu Feb 23, 2012 8:28 pm Post subject: |
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so what if the center line of the case isant the centerline of the crank?just thought I would throw that one your way to do some thinken on.you can make some rizors that aligine off the crank&cam, but you need to be able to make alowances for linebored cases(different size rizors).and make sure it is all rigid so you dont get no chatter or movement. an adjustable angle plate/rollover table is a great tool to add to your mill& there cheep.ebay/enco/shars. have fun. |
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mxracer Samba Member
Joined: April 09, 2011 Posts: 568 Location: NC
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Posted: Thu Feb 23, 2012 8:49 pm Post subject: |
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Mark.... if I'm understanding you right you are talking about the center of the spigot not aligning with the center line of the crank?
If that's that case what can I do about it?
I'm using a coax indicator to find the exact center (within .0002") of the existing hole then setting a cutter up to bore to 96mm for 90.5/92 and 97.3mm for 94. Am I overlooking something?
I'm looking at it just as I would using a boring head to enlarge a hole in a part. Find the center, setup the cutter, bore to new diameter. |
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mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
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Posted: Thu Feb 23, 2012 9:45 pm Post subject: |
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just think on it fer a while.if the case is bored .004 off of the case parting line you can still center up with the coax(I have the same thing to dial in locations) but that dosent make the deck straight just tells you your in the center of the hole. if the hole is up an inch and the other hole is down a inch you are still centered in the hole(x&y) but z is way off, or angled from 1 end to the other or top to bottom of case.I dont know if vw went off the crank & cam centerline to bore & deck these cases or not.cam location is needed to get the 90 degrees to the crank,or else 90 degrees to a round object can be just about anywhere whithen 360 degrees.but 2 centers gives you a located referance to work off of.or if you wish you can alter the case and have a V 4 engine.or what ever you come up with even a porkeypine layout,but these will affect a lot of things other than the way the tin & heads fit, like balancing& cam timing on all 4 cylinders.but for normal stuff that fixture would probably do just fine.but you should use a dial indacator to check the deck befor you deck it to see just what you have. if there is a problem dive in farther and messure the case bore halve at each bearing to see whats up.
on v8 engines it isant uncommon for 1 side to be up to .040 taller at 1 end and twisted. thus the reason for decking off the crankshaft center line. ( that is what the rods&pistons are supposed to be working off of)but a v8 you check 4 corrners at each side of the bore with 1 piston/rod & find out what it needs , up down twist,angle off or whatever.thats not as easy to do on these like that so it needs to be done on the case parealell to the crank&cam.if you have a dro on the quill &the setup off the crank&cam it,s easy to equalize both sides.a quil dro is cheep these days and makes thing very easy. |
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mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
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Posted: Thu Feb 23, 2012 9:49 pm Post subject: |
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I now see your dro,scratch that part.if you get any chatter . triangleate your fixture on the back side where it wont get in the way.(and pinn it if possiable so there isant anny movement. |
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modok Samba Member
Joined: October 30, 2009 Posts: 26787 Location: Colorado Springs
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Posted: Thu Feb 23, 2012 10:29 pm Post subject: |
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Wow, that fixture is a perfect example of how machinists think....
"lets take huge solid blocks of metal and bolt them together to make a huge solid thing that weighs 50 pounds! "
which is fine, that's why machine tools last so long
I would have welded together some angle iron....
Anyway, as per what mark is "saying", I disagree, fixturing off the line bore is more trouble than it's worth, unless you will be doing tons of them.
Heck I just bolt it down with the case halves assembled on a pair of cylinders, the few times I needed to surface one
To assure the deck is even and straight,
All you gotta do is measure the bearing bores relative to the case split, with a depth gauge, to determine if the line bore is true with the split.
If you find that it's say .003 deeper on one end(#1 compared to #3) , then you can just shim it an equal amount, so the deck height is the same and cylinders will be square with the crank
Nothing is ever truly square, the solution?, is shims
Now, if you shims are not exactly under where were measuring, then just put it in a ratio
THe bearing bores are about 9" apart, right? what if your fixture is 12" wide?.... .003 /9 *12= .004
so you could just put a pair of .004 shims under one side of your fixture and presto it's blueprinted race quality
THis may seem simple but I swear, some people don't get it
Also should measure the deck to case split distance before hand, so you can figure how what amount you want to take off both sides, even if they were not to begin with
write it in majic marker right on the case, can't lose the measurements that way
the cylinders centerline does not have to intersect the crank, that is not critical, many engines are off .030 and nobody knows, doesen't matter.
As long as the cylinder base is generally parallel to the case split it is fine
With that fixture it will never be too far off unless you forgot to tram in the mill. |
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luckystiff Samba Member
Joined: September 28, 2005 Posts: 2252 Location: hickory,nc
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Posted: Fri Feb 24, 2012 6:21 am Post subject: |
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stoked that i'm one of those local friends thats getting to be part of dan's new hobby.
i know dan thinks shit out from every angle and over does things so i have 1000% faith in him and his process.
getting that donor tore down and now having a NICE bare case sitting there already had the fire lit in me. this throws some gas on it. now if my money tree would just bloom ...ken.... _________________ ITMC
Secret Service |
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