Flathead Machine shop in Kansas City area?
- Thread starter dmar836
- Start date
Yeah that sounds like basic ignorance of machining unless it was that centerline shift thing.
I asked on the HAMB and, though there are many posts about the offset crank, nobody will answer as to how this effects boring the cylinders. Do you typically index off the crank C/L thus causing an issue or off the deck? I assumed the decks are perpendicular to the bores.
Any help there?
I asked on the HAMB and, though there are many posts about the offset crank, nobody will answer as to how this effects boring the cylinders. Do you typically index off the crank C/L thus causing an issue or off the deck? I assumed the decks are perpendicular to the bores.
Any help there?
Pete
BANNED
There are many different brand machines for boring blocks and several different methods for centering and squaring on the bore. First off, since this is about boring cylinders, we will assume you have checked the main line to see it is on size and straight.
Probably the oldest cylinder boring method was to first determine if the deck was good enough to re-use with slight cleaning with abrasive cloth wrapped over a flat file or straight edge.
Then the boring bar was set on the deck and centered on a cylinder AT THE BOTTOM where wear was a minumum. The block could be set up in a fixture or just propped up on the floor with wood blocks. This method relied on the original factory machining for the cylinder to be square with the crank centerline. For race engines, the deck was surfaced first to assure it was square with the crank. Kwikway, Van Norman and early Rottler's were examples of this type of boring bars.
Next, Rottler was probably the first to come out with a machine that set the block up on the crank centerline. They have an air gauge to determine if the deck is square with the crank. This type of setup has a big advantage in that if you have done any kind of repair on the deck, need sleeves surfaced off or it needs to be squared, the deck can be surfaced after boring the cylinders and be assured it will be square with the cylinders.
Next came the CNC machines that do several different block machining operations all from one setup. (and you can step out for a cup of coffee while the machine does the work)
Probably the oldest cylinder boring method was to first determine if the deck was good enough to re-use with slight cleaning with abrasive cloth wrapped over a flat file or straight edge.
Then the boring bar was set on the deck and centered on a cylinder AT THE BOTTOM where wear was a minumum. The block could be set up in a fixture or just propped up on the floor with wood blocks. This method relied on the original factory machining for the cylinder to be square with the crank centerline. For race engines, the deck was surfaced first to assure it was square with the crank. Kwikway, Van Norman and early Rottler's were examples of this type of boring bars.
Next, Rottler was probably the first to come out with a machine that set the block up on the crank centerline. They have an air gauge to determine if the deck is square with the crank. This type of setup has a big advantage in that if you have done any kind of repair on the deck, need sleeves surfaced off or it needs to be squared, the deck can be surfaced after boring the cylinders and be assured it will be square with the cylinders.
Next came the CNC machines that do several different block machining operations all from one setup. (and you can step out for a cup of coffee while the machine does the work)
Excellent info, guys. Thank you.
Just so I understand. If one bored the cylinders of these particular engines indexing off the crank C/L, they would cant the bore in relation to the deck? I assume that would also mean a huge cut to account for the mistake.
I have two shops recommended now but not sure how to ensure they know what to do.
Ask what kind of machine they use and that they index off the deck and lower cyl rather than the crank C/L?
Thanks for the explanations,
D
Just so I understand. If one bored the cylinders of these particular engines indexing off the crank C/L, they would cant the bore in relation to the deck? I assume that would also mean a huge cut to account for the mistake.
I have two shops recommended now but not sure how to ensure they know what to do.
Ask what kind of machine they use and that they index off the deck and lower cyl rather than the crank C/L?
Thanks for the explanations,
D
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They are just going to bore the existing cylinders oversize unless you tell them to do something different.
Bill
I agree with Pete. A basic street engine can be done with simple deck and original bores as locating points. The crank offset is absolutely meaningless for even modern fixturing and machines UNLESS there is the urge to also align the cam during the same setup.
As an aside, one of the engines in my cars I bored with a Kwik-Way of 1936 vintage with the original 1/4 HP motor on it. Yes, it was a elongated job. But, I did it because I could and to imagine what machinist encountered "back in the day". Way before I had powerful(and expensive0 options.
As an aside, one of the engines in my cars I bored with a Kwik-Way of 1936 vintage with the original 1/4 HP motor on it. Yes, it was a elongated job. But, I did it because I could and to imagine what machinist encountered "back in the day". Way before I had powerful(and expensive0 options.
JWL, I would do that too if I had that machine. I have a Kwik Way line bore setup and a valve surfacing machine. Also New Way seat cutters. Just no boring setup. I would enjoy doing it all myself the slow way.
Krylon32, I might consider that depending what the suggested Wichita shop says.
So, if the bore job is so basic, how do shops screw up flathead V-8s any more than an OHV V-8? What are all the flathead warnings about? I have passed on plenty of shop options(with less flathead experience) as I thought "they had to know flatheads". If there's nothing to be concerned about I wonder what the issue is?
Great help guys. I really appreciate the advice.
Krylon32, I might consider that depending what the suggested Wichita shop says.
So, if the bore job is so basic, how do shops screw up flathead V-8s any more than an OHV V-8? What are all the flathead warnings about? I have passed on plenty of shop options(with less flathead experience) as I thought "they had to know flatheads". If there's nothing to be concerned about I wonder what the issue is?
Great help guys. I really appreciate the advice.
Probably those who "screw up" a Flathead bore operation are addicted to the BHJ, or similar tooling, which align the cam line and crank line with the bores being set at 45 degrees. I thought I mentioned that problem?? Locating the block on the crank is not essential, nor has it been used for thousands of re-bored Flathead engines. Only the deck face and the bores are used for satisfactory alignment on a typical engine.