Every month, we receive emails from enthusiasts asking what steps should be taken to begin building his/her engine. The typical question would often look something like this:
"I own a '06 Mitsubishi Evo MR with plans to bore and stroke to a 2.3L displacement. Soon I will be taking the block and parts to a machine shop to have it inspected, cleaned up, and finally bored and prepped. I don't want them to build it for me, just prep the block so it is ready to go. I'll do the rest but I have a few questions:
1) What should I look for when choosing a machine shop (does it matter what type of equipment they use, what their steps/processes are, etc.)?
2) What procedures should I enlist the machine shop to prep the block, such as line bore/hone, decking, cylinder wall sonic testing, Magnafluxing, etc.?
3) What should I not have done (things that I would regret later on, or that could harm the block for the type of build I am doing)?
4) What should I expect to pay (so I know that I'm not being taken)?
Build it right the first time.
So what do you look for in a good machine shop? We'll try to shed a little light on the matter, so that next time you are hunting for the right place you know you're in good hands.
Foremost, the first and most important thing you want to address is knowing how you plan to drive your vehicle (time attack, drag, autocross) before you start your project. All too often, we hear about customers wanting a stout, reliable street motor who suddenly change their mind in the middle of a machine job and request that their setup spins to 8,000 rpm with the addition of a big turbo or nitrous, all while on a budget.
Choosing a machine shop for your engine rebuild can be confusing. There is a wide spectrum from which to choose. Your choice ranges between a one-man operation to a full-blown shop that employs over a dozen people. Which is right for you? The following will prepare you in choosing the ideal machine shop.
1) Machine Shop
Is the shop clean or messy? Most machine shops are typically cluttered, but on the flip side, a shop that is messy will typically reflect the machinist's work. A shop that is clean will have machinery that is clean. Simply stated, clean tools do their jobs better.
2) Types of Machinery/Tools
The defining characteristic of most shops is the type of machines they operate. Is the equipment new, top of the line, and well maintained? Many customers prefer old-school machinists using old-school machines, but take into consideration that as a piece of equipment gets older its ability to hold narrow tolerances slips, particularly if it has not been regularly maintained and periodically calibrated. CNC machines are regularly calibrated or replaced due to wear and tear issues every 10 years to keep up with newer, more improved technology.
3) Small Machine Shops Expertise
Never be afraid to ask questions, regardless of how foolish or stupid they might seem. Spend some time talking with the shop operator. It will become apparent very quickly if the operator is simply pushing parts or really applying professional machining techniques in every job. The more questions you ask, the better you should be able to sense their experience in the matter and how they handle a job. Your goal is to find a machine shop that is fast without sacrificing quality. If your machinist lacks communication or is not willing to discuss the engine process with you, simply pick up your parts and move on to another that can offer what you need.
Ask around. Inquire where friends/colleagues take their parts to be machined. Machine shops live off of their reputations, and happy customers can tell you a lot about their work. There's nothing wrong with comparative shopping. Inexpensive is OK; cheap is not. Much like many things in life, you get what you pay for. The better machine shops will not be the cheapest in town. Be prepared to pay for good service.