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Advice on automotive machining

Joined
Feb 25, 2022
I'm not a machinist by trade but wanting to start doing some automotive machining. I will be working only on cummins 5.9 and 6.7 blocks and heads. I want to be able to surface the heads and blocks, bore cylinders and drill the head studs and mains for larger fasteners. the blocks weigh 325 lbs, are 17 inches tall, 14 inches wide at the pan rails and 30 inches long. My question is would a vertical bed mill like dpm trak rx7, fryer mb14q or the like be adequate enough with respect to rigidity to surface blocks and heads maintaining <.001 variance over the 30 inch long block and head? I prefer to get a bed mill for it's versatility instead of buying dedicated surfacer and then still have to get something for boring etc. thanks
 

atex57

Hot Rolled
Joined
Sep 6, 2006
Location
SW Wisconsin
General purpose machines do not generally work well for engine work. If they did all shops would use them. Dedicated machines are much faster to set up and operate within their realm. If you do go with a GP machine buy it twice as big as you think you need. When decking an engine the cutter has to large enough to clear the block on both sides and travel beyond both ways on the ends. There is a reason for automotive shops.

Ed.
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
Those machines might do it. I don't think you have enough Z travel to bore. I think decking a 30" block would be iffy.

7500 lbs with 60" of X travel is a very light machine.

If you learn more about exactly what you need to do then picking the machine will be easy.

BTW, I have assembled many dozens, well over 50 B series Cummins engines. I own my own dyno. I machine the piston bowls and ring lands to suit my needs. I have CNC's that could do everything except hone the bores. I don't do the machinework because the shops that hot tank bore and hone a block, grind valves and cut seats do it perfect for so god damn cheap that it makes no sense. It costs $60 to clean a block like new. It costs $20 a hole to bore and CNC hone to my specs. It costs $150 to surface and do a custom valve job on a 12 valve head. If you want to comptete with that go for it lol!

The only reason I still assemble the things and do the custom machinework is because I can't find a local shop worth a shit to do that part. I have paid $12k-$15k a piece for 5 mild turnkey 12 valves. One was a great, troublefree runner. I won't even go into how many things other shops can fuck up inside an engine. If I need a big block chevy I know a dozen shops that can do it to my standards for under $10k. Cummins? "Diesel is for starting fires" they say.
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
Good to get the surface finish specifications needed, then consider machines that can make the grade.

Consider how the opposite side will be made true, square and flat enough to run the top side.

It may take a very good/top shape alternate kind of machine to perhaps do the task...other than the dedicated kind.
Likely top skills will be needed to fudge up an alternate method.

Back in the day, a grinder could do a very good job of surfacing, but now many heads ate aluminum.

QT Garwood [$150 to surface and do a custom valve job on a 12 valve head.] that seems a tough price to beat/match.

You might consider a used machine designed to do the task..and then be sure it is in good shape.

Resurfacing Machines | Jamison Equipment

The last head I had done needed a dowel for a crack.
 
Joined
Feb 25, 2022
Thanks buddy, I need a very smooth finish for MLS gaskets on the order of 15-20 Ra. I think I may go with a good heavy duty mill with DRO for small part machining with enough Z travel to drill the block, although I could use a magnetic drill for this. And buy a dedicated surfacer. I've got fixturing all figured out in my head, I can figure anything out I need to, just don't want to spend extra money on a machine and find out it doesn't work the way I want.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
I was looking at some newer machines about 10 years ago, forget mfr name, they were Spanish, maybe Italian, one machine that could do boring and surfacing of heads/blocks, and more mundane milling machine tasks. Appearance wise it looked like a jig mill, just lots more features, and it was pretty pricey new. If I was wanting to set up for diesel machine service, I'd try finding a used one priced right. Do some digging into the automotive machine tools category.

AERA used to have trade shows where you could see some pretty neat machines, just looked at the event calendar, all I'm seeing is the SEMA show, not sure if its the same.
 

slowmotion

Cast Iron
Joined
Mar 31, 2013
Location
Danville Virginia
If you are going to bore and mill, and no doubt sleeve, then you want an automotive bore mill. They are bed style machines that can handle a big inline. I had an RMC 1500, worked awesome for everything I wanted. They are hard to find used and you'll pay up for one but do not waste your time trying to make a machine work that is not designed for block work. Berco is also a name to look for.
 

MwTech Inc

Titanium
Joined
Feb 6, 2005
Location
Fishersville VA
You asked for advice........pay someone to do the machining.
Your post is totally illogical.

Your not a machinist.......
You want to buy machines not intended for that purpose "used", but you want super tight tolerances.......
You want to do basic low level engine work that any established shop can do ........
Really???

While you are "learning" the trade and you screw up your buddies block/head then what you going to do???

Funny thing, my two engine builders, (one general work the other race only, he does engines $50K and up) both have dedicated equipment for each procedure.
Wonder why?????
 
Joined
Feb 25, 2022
Listen here pal, I had never tig welded before, I bought a miller 250 synchrowave and in 4 months I was able to fabricate my own compound turbo piping. It looks very nice. I'm a physician by trade, before that a poor farmer that learned how to make do with anything. I've assembled many engines, high power cummins, 1000-1200 hp range. I've learned with some time and patience I can do a better job at what other "professionals" can do. There's two kinds of people in this world. Those who think everything they don't know is rocket science and those who know nothing is really rocket science. You're clearly the former, I'm the latter.
 

gbent

Diamond
Joined
Mar 14, 2005
Location
Kansas
Thats a lot of attitude for 4 posts. All we knew about you was a screen name that suggested little money. If you would have came right out and said "I've got more money than brains, and I'm pretty smart, help me spend my money, guys", we would have understood this was a hobby endeavor. We love to help other people spend their money.
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
There's two kinds of people in this world. Those who think everything they don't know is rocket science and those who know nothing is really rocket science.

You know there was a time when I would have wholeheartedly agreed with you on that. Like my dad would say when I was a kid "Yankee ingenuity can do anything".

I've made a pretty good living doing things the majority of people think is rocket science, but I've also been humbled a lot while learning how to machine stuff, design stuff and run a business. A lot more than I ever thought I would be. I don't think there's two kinds of people. I think there's a broad spectrum and each situation is unique.

I do not believe there's much about combustion engines that is really complicated. I spent the majority of the time I was supposed to be in classes during my Junior and senior years of High School scrubbing parts out of the hot tank for no pay, just the privilege really of hanging out and listening, learning in one of the best race engine shops in the Portland area. Like Friday night dirt track each class would have engines that came through that shop 1-2-3. The local gear shop owner knew that a 600HP BBC from that shop was going to destroy axles and other parts that any other builder's "1000 HP" big block would be fine with.

What I took away from that experience is that building an engine starts with a plan and requires incredible attention to detail and the experience to know where to focus that attention.

Sure you can probably figure all this stuff out, but you gotta have some serious, expensive machines to do better than the guys charging $20 a hole. So why?

CNC hones start at $50k last time I looked. I would buy a really high end used Japanese VMC with scales and 60" of X travel just because I will believe it when a Kuraki or Mori tells me a position is right on or that shit is straight. And I can probably find a nice 1990's one for less than that shitty 7500 lb engine builder specific turd thing.

Then you need a ton of other stuff. What else do you want to do? Main line work? Crankshaft mods and grinding? Head work?

I think a guy could piss away a quarter mil real quick just for the excitement of handling 325 lb blocks and fixing holes for $20 a pop for cheap fucks who complain about the prices.
 

Milland

Diamond
Joined
Jul 6, 2006
Location
Hillsboro, New Hampshire
I think a guy could piss away a quarter mil real quick just for the excitement of handling 325 lb blocks and fixing holes for $20 a pop for cheap fucks who complain about the prices.

Hell, I'm staggered that someone can make money at $20/hole for boring and honing. Even with top-flight equipment, consumables and setup time would eat that up real quick. And, umm, the cost of the machine has to figure in all that too...
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
Hell, I'm staggered that someone can make money at $20/hole for boring and honing. Even with top-flight equipment, consumables and setup time would eat that up real quick. And, umm, the cost of the machine has to figure in all that too...

The best "bore this block this size" shop I have used in 25 years of doing this is a Napa machine shop that serves about 25 stores. They are busy as fuck. I don't know if the machine shop makes money, but it keeps customers buying parts.

Note: I would never have them complete an engine build for me. I will soon be building an AMC V8 for a car my dad bought bought new and I will take it to a race engine builder I trust (the guy who took over the shop I pissed away my youth in) and have the works done. No point in practicing on something I want perfect. I will pay the price of admission.
 

Turbowerks

Cast Iron
Joined
Nov 9, 2018
Location
Windom
You want to play diesel cummins engine builder guy? Get in line. Listen to some of these other guys and me . Ive done it started my business 30 years ago got some worn out automotive machines ( not big enough but the salesman said it would work) then a big ass burgmaster nc mill
Weight 25000 pounds for a 40ish x travel could do lots on it but painfully slow setup and fixturing
Fast forward 15 years Rottler boring machine f2b i think it was and a berco cbn surfacer i thought i was in heaven but 50000 less in my checkbook with the tooling. Oh ya valves were old school grinding worked but not nearly up to speed for any type of performance . enter crank grinding, cam grinding crank welding all berco machines, welding by gleason. Baskets of cash for that.
Then the berco f84 cnc block machining center , surfacing, boring , line boring misc general machine operations , tooling cost more than the machine and the machine is lots. Oh ya honing too. Or go find a 6030 fadal can do most operations on that for 10000.00 as long as your only going to do the cummins thing.
Better find a rich uncle.
One last thing 20.00 a hole to bore or 150 for surface and valve service im not even going to open the door. All the old parts store shops are running off 1940-60 machines don’t get me wrong some of those guys have mad skills and do incredibly good work , they have also run those same machines since they were new.
Have a fun journey i hope the best for your endeavor.


When I find it I don’t need it
When I need it I can’t find it!
 

CITIZEN F16

Titanium
Joined
May 2, 2021
I remember when every other independent auto parts store had a machine shop in the back, those days seem long gone. I have a lot of varied skills and a few things I stunk at. I would not consider machining an easy skill to pick up. I agree with the others dedicated machines are the way to go. I did a valve job once in the shop I worked at on standard machine shop equipment. It took way longer than expected.
 

slowmotion

Cast Iron
Joined
Mar 31, 2013
Location
Danville Virginia
Most folks really have no idea how the automotive machining industry has evolved. 25 years ago, a bore mill replaced portable boring bars, Rottler F series, and surfacers. One machine could it all with more accuracy and one setup. Now, shops that stay ahead of the curve and make money have 4 axis CNC mills and automatic diamond hones. We can do a lot more a lot faster and with even more accuracy. The shops from the 70's are dying every day. These are the shops that still bore for $10 a hole and grind cranks (poorly) for $100.

Some areas of the country haven't caught up with the technology so guys who cannot get it done right locally often try to do it themselves. Most of the time they buy junk from these dying shops and quickly fail themselves. If the OP chooses the right equipment (bore mill and a CV616 Sunnen at a minimum) he'll do fine with his specific market. Boring and decking is not rocket science, good equipment makes it easy. That covers blocks, heads is a whole other area which I would caution the OP to stay away from. It takes a lot more heavier equipment to do inline diesel valve work correctly. No modern shops grind seats, they are cut on a dedicated machine. If he were to get into head work, it would also become a full time job, stick with blocks only.
 

jim rozen

Diamond
Joined
Feb 26, 2004
Location
peekskill, NY
... two kinds of people in this world. Those who think everything they don't know is rocket science and those who know nothing is really rocket science. ....

Hmm, parse that out a bit. Rocket science, what is it? It's engineering where it's never been done before - where the biggest problems are the "unknown unknowns." That is, the problems you are up against, are ones you can't even comprehend at the start. Want to build an F1 engine that does not explode on the test stand? Nobody can tell you how to do that, good luck. That's rocket science. Want to make money doing automotive machining? Yer in luck, OTHER PEOPLE have done this and can tell you their stories.

Stopper your ears, ignore them - at your own peril. My personal suggestion: sponge up every tidbit and thank all story tellers profusely. Your call.
 








 
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