I too have been thinking about one of those ones from Ebay but think the probe needs to be a ball shape or very small. How has it been working with that .375 probe?

Mike, did ya get a chance to try that tester out yet? ebay has a gm100 tester also, think its any good?

I want to buy a tester as well. have 2 blocks to check. I read if you modify the probe/transducer it will read inaccurately. so whats the solution with this issue?

do they read 2 pieces of the same material pressed against each other? you could make a cast iron adapter that looks like a D then it would be reading - adapter = wall thickness. I'm guessing it messes up though, and the materials would need to be the same.

which tester do you have? i'm looking at the one mike bought and the gm100 for about $100.

I bought my tester from a company called Testing Equipment based out of Houston, TX. The same model is probably available for less from some of the China-direct vendors on eBay, but I wanted a USA point of contact to scream at should something go wrong w/ the deal.

They offer(ed?) two versions, the MT150 and MT160. I bought the 150 version because it was less expensive, but maybe should have bought the 160 in hind sight. The key functional differences are (a) the 160 gives readouts to .00x" accuracy (e.g., .157") and (b) has some PC download capability that I don't need. The 150 reads to .0x" accuracy, (e.g. .16"), which is fine except on the thinner readings such as .08", so I don't know if the wall thickness is closer to .076" or .084".

The vendor offers the same testers with different probes / transducers. I purchased mine w/ the N07 model, which has a 6mm diameter face and is the smallest they offer. I contacted them directly about buying a second N07 at the same time, because I suspected I was going to have to hand-fit one of them to read the curved surface of a cylinder bore properly... and I was right. I spent some time w/ 600-grit wet-or-dry profiling the face of the probe to have a convex surface that appeared to seat properly against the inside of my 4.375" tapered ring compressor.

Although the instructions give some different methods for calibration, especially considering I was working w/ curved surfaces, I think the best approach was the one that AndyF suggested: measure the thickness at the top of two adjacent cylinders w/ a caliper, then take a reading w/ the tester at the identical spot and calibrate the tester to match that.

I don't recall the cost of the individual components, but the invoice I found for the total transaction (sonic tester kit w/ probe) was just under $400. IIRC, the 160 model is $50-60 more, which I didn't feel was worth it at the time.

I hope this helps. I've used the tester to read a couple of different 440 blocks and have been able to get consistent readings after finding the best calibration approach and some hands-on experience to get the best "feel" for positioning the probe, etc.

yes, thanks.

I finally found some one to check my block, never dreamed it would be this much trouble. I've called machine shops and engine builders within about a two hour radius from me with no luck. I finally talked to a guy in Nashville who gave the number of a guy, who gave the number of a guy that had one. He had a small one man machine shop but quit and went to work at a power plant and kept all his stuff. He's about an hour away and is going to check two blocks for me next week .

cool! i'm going to buy my own tester as there's a lot of shops that don't offer that around here. just waiting on mr p to test his out to see if he likes it as that is the same tester im looking to buy.

I looked on the bag but not knowing if the transducers would work kept me from buying. It appears that the plugs on the transducers are standardized. If that's the case you could buy the correct one from Dakota for about $300. My only question would be if the unit would operate in the correct frequency.

my plan is to mod the probe and buy a second probe if I ruin it with the mod.

I bought my Dakota tester years ago. To me, if it's not certifiable (none of the cheap ones are legal for testing when results really matter) it's not much better than visual and weight inspections. You can pay a couple hundred and still cost yourself a couple grand later. They also gave me a crash course on proper testing and have a file of what I bought, and have been great to talk to over the years when i had questions.
Personally, not having any background in how they work or thier design, I would never modify the transducer. They tell me not to. I figure they should know...lol. Good companies offer a variety of them for ferrous and non-ferrous metals and various radii. Mine has paid for itself over time but it's also saved me from making an expensive mistake or two - so I'm way ahead.

Moper can you post a good clear close up photo of the lead plug ends on your probe?

How about some updates pictures of probes etc. Im still looking into buying one. Mr Pbody did you test yours yet?