Advice on automotive machining

[DDoug]

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.

Clearly you've been given good advice, and you post this ? ^^^
Please leave NOW.

 

[CarbideBob]

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...

Sort of depends on volume.
Lets see numbers. A 6 station transfer line rough bores, finish bores, and hones 6 cylinders in 60 seconds or less.
So that is 360 holes per hour or $7200 per hour at 20 bucks each.
Oh, maybe this is a bad example... _
Bob

 

[Milland]

Gol dangit, Bob - don't go using your fancy-pants knowledge and experience on me!

Or, show me the cost of that transfer line that can do a whole bunch of different blocks brought in by Billy-Bob-Smith and his kin, each with it's own bore size, depth, and deck height, in 10 seconds a bore.

 

[Garwood]

Local Napa upgrades machines every few years to the latest new stuff. They have four guys working 6 days a week. I know the CNC hone is very fast, but I don't know the total time for bore/hone with setup. I wouldn't be surprised if it was less than an hour total. They send out Cranks and cams. They do all the headwork. I make custom tools for them on occasion.

They still charge $20/hole, but I don't think the goal is to make money. The goal is probably not to lose money and keep their large customer base through providing parts and service.

 

[boslab]

Damn the lot of you, my mag drill has been putting holes precisely for 25 years, ok precisely where they weren’t supposed to be but I’m working on it!
If you don’t laugh you’ll cry,
Mark

 

[dalmatiangirl61]

You guys have not even touched on the most important part of an automotive machine shop, the cleaning dept. If I could figure out a way to get customers to bring me spotlessly clean heads, I would gladly buy some nice head equipment. I started in the cleaning dept, god that was a nasty job.

 

[CITIZEN F16]

You guys have not even touched on the most important part of an automotive machine shop, the cleaning dept. If I could figure out a way to get customers to bring me spotlessly clean heads, I would gladly buy some nice head equipment. I started in the cleaning dept, god that was a nasty job.

Have they come up with anything decent to replace the banned cleaning chemicals of the past? I know a lot of things you can buy in the hardware store aren't legal to use in a business, and those that are seem much weaker than days gone by. I fortunately have not had a nasty cleaning job in decades.

 

[Garwood]

Have they come up with anything decent to replace the banned cleaning chemicals of the past? I know a lot of things you can buy in the hardware store aren't legal to use in a business, and those that are seem much weaker than days gone by. I fortunately have not had a nasty cleaning job in decades.

Nothing really works better for ferrous and red metals than lye at 200 degrees. Aluminum is different. I don't know what the cleaners made for aluminum are based on, but they work well enough.

 

[slowmotion]

Automotive machine shops today have enclosed spray wash cabinets and most use an aluminum safe cleaning solution, which works well as it is heated to 165-175 degrees. Soda blasters can remove any excess carbon buildup (common with today's direct injection)and is the safest to use, as soda dissolves in water. Some shops have steel shot machines for cast blocks and heads but it's a nasty noisy high maintenance operation. Cleaning is definitely a big part of the job and it's expensive to have the waste hauled off legally. I'm glad I won't have to deal with it myself for much longer, one of my customers is buying my shop. Retirement here I come.

 

[Turbowerks]

The cleaning aspect is certainly a challenge. My dept is almost in need of its own building and im not that high of volume , jet washer, hot tank, glass bead cabinet, soda cabinet. Shot blaster and ultra sonic. We stiil find ourselves using a steam cleaner manually with some items. Oh ya that dam rust remover for the junkyard cores and restoration. Major expence that some people think is a freebee.


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

 

[PackardV8]

The good news for a hobby shop is with EPA restrictions and labor costs going up and old guys retiring, many of the small-to-medium automotive machine shops have already gone or are going out of business.

NAPA was mentioned. Fifty years ago, a dozen auto parts store in town had an automotive machine shop in the back room. Today, none of them in Spokane do. We have a regional NAPA warehouse and they closed their machine shop twenty years ago.

It has never been easier or less expensive to set oneself up to get dirty and lose money by doing his automotive machine work.

We see turnkey automotive machine shops, granted with 30-to-50-year-old machines, being sold for less than $100,000. Many of the machines end up in shipping containers bound for Thailand, et al.

A hobby guy who has some experience and talent, could be doing everything necessary for a precision engine build. It would take him less than ten years to master all the processes and learn the quirks of all the older machines.

That's if he never opened the doors to any walk-in business or answered the phone from the wannabees looking for precision custom work at last century prices.

jack vines

 

[1yesca]

You guys have not even touched on the most important part of an automotive machine shop, the cleaning dept. If I could figure out a way to get customers to bring me spotlessly clean heads, I would gladly buy some nice head equipment. I started in the cleaning dept, god that was a nasty job.

yup that's were we all started ! in tear down ! but its the most important dept. in the shop ! if you have a good crew that cares about what there doing it makes thing so nice.the sad thing is most of the young bloods are afraid to get dirty and like it or not that's part of the gig.

 

[BT Fabrication]

Nothing really works better for ferrous and red metals than lye at 200 degrees. Aluminum is different. I don't know what the cleaners made for aluminum are based on, but they work well enough.

Usually acid based with some sort of degreaser. same as fuel tanker wash.

 

[redneck engineer]

Thanks, most of the responses were very informative. Honestly, I guess most would consider me to be the type with more money than brains. I'm gonna find a decently priced bed mill that I know will work great for drilling mains and head studs (40 taper machine) and try out a flycutter with cbn insert for surfacing. If it doesn't do what I want I'll look for a good used surfacer, seems like they can be found for 20k or so to start off. To answer one of the posters, I don't plan on doing any head work just block stuff which is pretty straightforward, although I know theres a learning curve with a new machine like anything in life. As for the sarcastic response I gave earlier, it seemed to rub a few wrong but I didn't throw the first swing. I'll always be glad to oblige a counter however.

 

[PackardV8]

Thanks, most of the responses were very informative. Honestly, I guess most would consider me to be the type with more money than brains. I'm gonna find a decently priced bed mill that I know will work great for drilling mains and head studs (40 taper machine) and try out a flycutter with cbn insert for surfacing. If it doesn't do what I want I'll look for a good used surfacer, seems like they can be found for 20k or so to start off. To answer one of the posters, I don't plan on doing any head work just block stuff which is pretty straightforward, although I know theres a learning curve with a new machine like anything in life. As for the sarcastic response I gave earlier, it seemed to rub a few wrong but I didn't throw the first swing. I'll always be glad to oblige a counter however.

You're determined to learn why bed mills aren't the preferred method of surfacing Cummins blocks, so go for it.

Actually, surfacers are just very large, very rigid, very specialized bed mills.

BTW, never set the pan rails on the mill table and assume they are parallel to the main line bore. Sooner or later, you'll find one which isn't and the piston deck height goes caterwhompas.

The Storm-Vulcan 85B block master can be had for less than $10,000.

jack vines

 

[CarbideBob]

The problem with using a normal cnc mill for decking blocks is that you want to swing a very big cutter that is not going to fit in the toolchanger.
Ideally the cutting diameter is at least twice the width of the block face.
Second is that machine spindles for doing this are not set straight and square like a normal cnc mill.
They are tilted ever so slightly.
CBN is good in cast. Contrary to conventional thought small corner rad on the insert is good as this gives less rise and fall as you cross the holes.
Zero dish cutters or a wiper eliminate the need to have all teeth at the same cutting height.

Unsure on which the pan rail is not the machining datum. That seems complicated in production on a line and brings about all sorts of questions.

Bob
(two cents from the peanut galley, just some thoughts and I have never done the make a living rebuild thing)

 

[PackardV8]

Unsure on which the pan rail is not the machining datum. That seems complicated in production on a line and brings about all sorts of questions.

Bob
(two cents from the peanut galley, just some thoughts and I have never done the make a living rebuild thing)

Bob, if one has ever watched an OEM block transfer line at full speed, it's amazing the finished product resembles the blueprint as closely as it does.

The reason surfacers mount the block on a bar through the main line and not conveniently on the pan rails is because sometimes things aren't as they should be and general agreement is to use the main bores as the reference. If the block deck is finished parallel to the main line, the piston deck heights are the same front to rear. If the block is finished parallel to the pan rails, sometimes the piston deck heights will vary front to rear.

While OP is only concerned with inline Cummins, there's also a reason a fixture exists to provide verified ninety-degree surfaces on V8 blocks. You'd be amazed at how far off the millions of small block Chevrolets were and ran a hundred thousand miles in their first life.

jack vines

 

[gbent]

I'm pretty sure Bob has spent more time watching transfer machines than any other regular poster here, probably by orders of magnitude.

Rather than trying to mess around with locating off the mains, it would be better to verify the main bore to pan parallelism. If its off, move to another block. Chances are there was a problem making the block and other features are likely to also be out of location.

 

[john.k]

Unfortunately ,with Cummins 6 L blocks ,you cant just discard one cause its slightly out of square,or a couple of head bolt holes are nasty looking...cause they cost money.....touching the rear housing mount face is a no no too,according to some,but Ive cleaned up block faces where a housing has come loose.

 

[john.k]

And $20 a hole rebores?...more like $100 for a backyard shed portable ,or the local big engine shop.....$200 a hole minimum....and crank grinds?....start at four figures for a crank that doesnt need a special wheel.......which is just about every diesel................and oddly enough,local big engine shop is in a flood zone,and probably flooded two weeks ago.....I think they own the building,no reason to stay otherwise.