Centroid Performance Racing

Centroid Performance Racing

The world's #1 choice for performance racing machine tools.

B4250 CNC Engine Block Machining Center

B4250 4-Axis CNC Engine Block Machining Center

Flexible fixture and software allows for easy machining of any block

Discover the CENTROID advantage with the B4250: we provide the machine, tooling, software, and personalized on-site training you need to blueprint, machine, and rebuild engine blocks. In addition to the included ready-to-run block programs, our conversational software gives you the power and flexibility to easily add new engine blocks and operations, so you'll never need to purchase additional programs or edit G-code. CENTROID puts you in control of your shop!

Quick links: B4250 Brochure (PDF) | Request a quote or in-person demo | Call for a quote or Demo

CNC Engine Block Machining Center

B4250 Turnkey Package Includes:

  • 4-axis machining center
  • M400 CNC control
  • Universal block fixture
  • Conversational block software
  • On-site personalized training
  • Standard tooling package
  • Digitizing probe
  • Auto tool length setter
    • 24-tool automatic tool changer (ATC)
    • MPG electronic handwheel
    • Industry's best warranty & support

The B4250 is a complete turn-key CNC engine block machining package. We supply the accessories, tooling and the training so you will be blueprinting and machining blocks in no time.

The B4250 will CNC blueprint an engine block faster and more accurately than the competition. Equipped with a 24 tool automatic swing arm tool changer, CENTROID has made advancements to the machine, the block fixturing and the CNC control that allow you to produce accurate race winning cylinder blocks quickly and easily.

The CENTROID patented digitizing probe will automatically determine the location, diameter and angle of any feature on the block. CENTROID's easy preprogrammed conversational cycles take the hassle out of programming. No G code experience necessary. The actual cnc blue print information is displayed on the screen beside the factory information. Both a table and a graphic display shows the operator the differences, choose to make the appropriate adjustments and then automatically CNC machine the block to the new specifications.

Download Hi res B4250 Brochure in PDF






Included standard tooling package

Included Standard Tooling Package

CENTROID includes a high quality tooling package with each machine to get you up and running quickly!

  • Cylinder boring tool
  • Tool setting micrometer
  • 12" deck surfacing tool
  • Lifter boring tool
  • Lifter spot-facing tool
  • Cylinder chamfering tool
  • Main cap conversion tooling
  • Digitizing probe and stylus

CNC Block Blueprinting with the DP4 touch probe

Automatic CNC Block Blueprinting: CNC Probing

Blueprinting any block begins by making very accurate measurements of the existing features so corrections can be made. The old way of laborious manual measurement has been eliminated. The CENTROID B4250 CNC Block machine is equipped with a high tech digitizing probe which automatically locates and measure cylinder bores (diameters, locations and angles), deck heights, and lifter bores with our exclusive easy to use block specific conversational software. To measure an entire block, simply choose the features to blueprint and the probe automatically measures the block and displays the actual diameters and positions of the cylinder bores (and other features) and compares it to the factory specs. The operator then chooses to make any modifications necessary.

The CENTROID DP-4 Probe is a state of the art, made-in-USA highly precise probe which can detect in all axis and directions. Since the probe is made by CENTROID the entire probing system is integrated and streamlined into the CNC machine, making block digitizing and probing a quick and simple process. Much more accurate, faster and repeatable than manually blueprinting a block!

Cylinder Boring

CNC Engine Block Cylinder Boring

Automatic Boring cycles are pre programmed and are menu driven with a simple fill-in-the-blank format. 360 degree CNC rotary axis will position the block at the exact blueprint angle automatically. Machine both cylinder banks with the same setup. Block database saves your work for future jobs. Bore on probed centers, blueprint, or any other specified location. Specialized boring tooling included. Quick, simple programming gets the job done accurately the first time. Operators program the block work to be done right at the machine.

Deck Surfacing with the CENTROID Flycutter

CNC Engine Block Surfacing

With a quick push button tool change the machine will surface the block to the exact deck height specified. The probe automatically detects the block existing surface height at multiple locations so the operator can choose the proper surface depth to machine to for a perfectly flat and square deck to the cylinder bore. Specialized CNC block surfacing tooling is included which produces incredibly smooth surfaces for superior gasket performance.

Lifter Bore Spot Facing

Head Stud conversion, automatic, drill, counter bore and tap... just takes minutes.

Convert blocks for head studs with ease. The machine will automatically drill out the exisiting threads counter bore the lead in and rigid tap (or threadmill) the threads to accept the new head studs. The CENTROID user friendly CNC Block software is conversational format which means all you have to do is fill in the blanks with the basic block information, no need to go out of house or learn G-codes, our easy to learn Block Software is made specifically for engine builders saving you time. You can save all of your programs and base new ones off of existing work, building a custom group of block machining programs specific to you applications!

Lifter Bore Spot Facing

CNC Spot Facing

Spot Face Lifter bores automatically. You have the ability to create and save your programs with CENTROID user friendly CNC Block software. No need to go out of house or learn G codes, our easy to learn Block Software is made specifically for engine builders saving you time.

Lifter Boring

CNC Lifter Bore Machining

Machine lifter bores to the exact diameter, location and angle needed with one simple setup. True up the stock size and location or bore complete new diameter, location or angle. Easily control feed and speed within the CENTROID conversational block software, the computer remembers your data for the next job as well, no need to reprogram. Easy manual override of programmed feeds and speeds via the operator control panel makes fine tuning adjustments easy to do on the fly.

Main Bearing Cap Conversion

4-Bolt Main Bearing Cap Conversion

The best way to accurately convert a block to 4 bolt mains. Automatic CNC drill and tap routines are pre programmed, the operator simply answers a few questions and the machine does the rest. CNC Angle Drilling and tapping for perfect 4 bolt main conversions. Straight or Splayed 4 bolt mains are no problem.

Cylinder Bore Chamfering

Cylinder Bore Chamfering

Chamfer cylinder bores automatically. Operators specifies amount of chamfer. Machine chamfers perfectly concentric with bore.

O-Ring Grooving

O-Ring Grooving*

Add o-ring grooves the the deck of any block. Any width and any depth, operator specifies oring specs and the machine does the rest.

* O-ring tooling is optional.

Grid digitizing a block face to create the profile

CNC Block Lightening

Automatically remove excess material. The probe copies the shape of the block and creates a tool path that perfectly matches the contour of every detail.

Choose the amount of material to remove, press cycle start, and the tool will machine the block surface to your specs.


A specified amount of material can be removed.

Threadmilling of Freeze Plug hole.

Threadmilling freeze plug holes. (and other threads)

CENTROID threadmilling canned cycle provides easy fill in the blank programming. Threadmill the threads on blocks and heads. Never break a tap again!

When should a thread mill be selected over taps?

In general, for production threading up to 3/8", taps are more efficient. However, if producing a wide variety of parts, threads, and materials on the same machine, threads mill are far more versatile. They will produce right or left hand, internal or external threads, single or multiple lead from #2-56 with the same mill. Materials range from soft, non-ferrous alloys to heat-treated steels, or tough alloys such inconel and titanium, where tap breakage often occurs. Pipe threads are easily produced without leaving the normal “stop lines” and creating the troublesome stringy chips normally produced by taps. In addition, thread mills can produce full threads to within one pitch of the bottom of a blind hole.


Engrave letters, numbers, and logos.

CNC Engine Block Engraving

Quickly and easily engrave letters, numbers, symbols and logos. Deck heights, phone numbers, serial numbers, web addresses and company logos are now simple to automatically add onto every block you blueprint.

Stroker Clearance Machining

Stroker crank clearance machining.

Easily machine clearance paths in the block for big stroker cranks.

Cylinder Head Surfacing.

Cylinder Head surfacing! Acheive incredible Ra's.

Switch from Block work to Cylinder head surfacing in minutes, surface heads better and faster than a dedicated surfacing machine. Super Low Ra's will make your customers happy.


Download the B4250 Specification in PDF, click here.

Engine Block Machine Specifications

Machine Features:

  • M400 CNC control, Touch screen, Windows 10 OS, Quad core processor, SSD,USB,Wifi
  • Full Enclosure w/ chip auger
  • Laser calibrated for high accuracy
  • C5 double nut ballscrews
  • Heavy duty linear ways
  • Arm type ATC 24 tools
  • Meehanite Casting Stress relieved
  • Spindle chiller
  • Auto Tool Coolant system
  • Telescopic steel way covers
  • Auto central lubrication system
  • Disc type oil/coolant separator
  • Safety glass front

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Engine Block CNC

CENTROID M400 Conversational CNC Control

Our CNC Block conversational software is a integrated part of the control system. This quick and simple to use Block specific software guides you thru the process with graphics and a simple fill in the blank format. Our Block blueprint data base is standard and expandable, nothing extra to buy. Operators can easily add their own work to the data base. The control remembers all your data and programs. Easy transfer to a USB thumb drive for backup & safe keeping, USB 2.0 ports are a standard feature of the PC based CENTROID cnc control along with a robust solid state hard drive made for harsh environments for reliable operation for years to come.

Touch screen, Windows 10 OS, fast Quad core processor, SSD,USB, and Wifi for remote live support! A large color LCD screen with an anti glare layer makes the control easy on the eyes, grease and chip proof. The operator control panel has dedicated buttons for common machine functions that makes the control simple and intuitive to use. The included electronic remote hand wheel makes block setups quick, accurate and easy. Simply turn the dial to move a machine axis, a selection of increments on the dial allows fine adjustments. The control stand itself allows and operator to stand or sit with a comfortable working position.

The CENTROID M400 CNC control is a full function 4-Axis CNC that has additional built in conversational pre programmed canned cycles for everyday machining tasks, such as automatic pocketing (circular, rectangular, irregular with cleanout), drilling cycles( peck drilling, deep hole and regular), Tapping (compression, reversing and Rigid! w/ special deep tap cycles), Frame milling, Engraving, Lines, Arcs, repeat, rotate, mirror, depth repeat and much more... In addition to the extensive conversational software the CENTROID M400 is a G and M code CNC control which uses industry standard G codes so you can use any CAD/CAM system to program a part.

CNC Block software Anyone can learn how to run CENTROID's CNC Block software in an afternoon. CENTROID has simplified the block blueprinting and machining process. Common block operations have been preprogrammed for you. There is even a built in data base of factory blueprint data for common blocks. The digitizing probe automatically locates all the key dimensions of a block, the data is displayed on the screen and is compared to the blue print info. The operator can choose to machine on blueprint or at any other location. Simple fill in the blank menus with an easy to understand format will have you CNC'ing blocks in no time. You can base a new program on an existing program, so you don't always have to start from scratch, all your programs can be saved and backed up to a USB stick, LAN or back up hard drive. No out of house programming is required, you are in control of your own designs.
CENTROID CNC Training is comprehensive When you go with a CENTROID, you'll receive comprehensive one-on-one machine and control training from our dedicated staff. We been teaching shops the tricks of the CNC trade now for 30 years. Let us show you how a CENTROID CNC machines tool can increase both an engines horsepower and your bottom line.
  • Every training custom tailored to each customer, no cookie-cutter trainings
  • Personalized service and support
  • Direct support phone numbers, no automated systems or in between people
  • Remote troubleshooting, programming questions, and diagnostics right on the control
  • One support number to call for every single component in the system
  • Support available outside of 9-5 M-F
  • Expedited parts & accessories service, with in house machine shop, keeps you up and running.
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