The question is always the same: how much material is left between the bore surface and the water jacket. It cannot be seen from outside, it cannot be measured with callipers, and getting it wrong means a failure on the track.
- ✓ Remaining thickness between liner and water jacket
- ✓ Documented decision on reboring
- ✓ Grid of points along stroke and circumference
- ✓ A-Scan on the RX8-DL to validate the reading on a curved surface
- ✓ Data logger: the map of the block stays on file
- ✓ Non-destructive inspection, repeatable at every overhaul
A used engine block has a value that depends entirely on an invisible figure. If it has been rebored once too often, the wall left between the bore surface and the water passage may already be at the limit; if it is still untouched, it will take another oversize. From outside the two cases look identical, and no mechanical measurement reaches that position.
Ultrasonic measurement settles the matter by resting the probe on the cylinder surface: the time of flight to the water jacket gives the wall thickness directly. Repeating the reading along the stroke and around the circumference builds the real profile, which is almost never uniform: core shift in the casting and previous rebores leave some zones thinner than others.
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With the model equipped with a data logger that grid is stored and becomes the map of the block: comparable with other engines, reusable at the next overhaul and attachable to the engine’s documentation when it changes hands. That is the difference between a measurement and a figure that holds its value over time.
R9 or RX8-DL
| Feature | Dakota R9 | Dakota RX8-DL |
|---|---|---|
| Thickness measurement | Yes | Yes |
| A-Scan display | No | Yes |
| Data logger | No | Yes |
| Mapping of the block | On paper only | Stored in the instrument |
| Typical use | Quick check in the workshop | Engine preparation and history |
Why the A-Scan matters on a curved surface
Inside a cylinder the geometry does not help: the surface is curved and the opposite wall is not parallel.
- The curvature makes coupling the probe more critical
- The backwall echo can be weak or split: without the A-Scan there is no telling
- The internal ribs of the block can generate intermediate echoes
- The A-Scan shows where the gate has locked on and makes it possible to discard a wrong reading
On a part where an error has consequences on the track, being able to look at the waveform is worth the price of the feature.
Recommended instruments
| Instrument | Why in this application |
|---|---|
| Dakota RX8-DL Sonic Tester | A-Scan and data logger: complete mapping of the block |
| Dakota R9 Sonic Tester | Essential measurement in the workshop, without storage |
| Dakota PMX2-DL | When resolution down to 0.001 mm on machined components is needed |
| Dedicated probes | The probe suited to the curvature is part of the solution |
Frequently asked questions
No, and that is exactly the point. The block has to be accessible with the probe from inside the cylinder, but it is not cut or sacrificed: the measurement is non-destructive and can be repeated on the same engine at every overhaul.
Enough to cover both the stroke and the circumference, because the wall is not uniform: core shift in the casting and previous rebores create thinner zones. The grid is set according to the geometry of the block and to how much margin is being sought.
It depends on how liner and block are mated: ultrasound does cross the interfaces between different materials, but every transition generates an echo and the result has to be interpreted. The case has to be assessed in practice: tell us the material, the type of liner and the geometry and we will confirm whether the measurement is reliable.
Back to Automotive and Motorsport. To choose the Sonic Tester, write to us stating the type of block, the material and whether you need the map to be stored.
Further information and contacts
Systems division and sensor integration partner : www.roder.it
More information about RODER SRL : about us
Contact for general information : info@roder.it
Contact for information about these products : info@roder.it
The information contained on this web page is provided for information purposes only. Although it has been compiled with the utmost care, it does not constitute a contractual offer or a binding commitment to supply. It may contain transcription, translation or typographical errors. For precise and up-to-date information, please contact our company directly.
Some images on this website have been intentionally generated using Artificial Intelligence (AI). This is because, for many applications and projects, it is not possible to disclose photographs of the installation or of the actual system due to confidentiality agreements, confidentiality clauses and non-disclosure agreements (NDAs).