Has anyone used the $100 sonic testers from eBay for thickness testing on cylinder walls, etc.? What were the results, are they any good? Here is an example:

http://m.ebay.com/itm/321336644253?nav=SEARCH

thanks, Joel

almost worth buying and sending it thru the calibration lab at work just to find out.

i was looking into it also. from research i gathered to get a bunch of spare pickups and grind them so they work in a round bore because they are for flat surfaces.

not the same one but yep an Ebay sonic tester, works ok, have to use some emery on a flat surface & put a slight curve on the sensor so it has full contact with the curve of the cylinder bore

heck just get it at 65 bucks. that is only 6 gal of fuel some burn in the hot rod in a day

Plus a shipping fee of $29 (from China) which makes it $94. Interesting though....

Are the pickups readily obtainable, and for how much? May be fun to kick around.

Dan

Well, I just pulled the trigger on one. $89.00 with free shipping and a padded metal box. About the cost of 1 professional sonic test. I am wondering if extra stylus are even available. I guess I'll find out

I was looking at those last week and was wondering the same thing.
After you get it, report back as to how accurate it is.

The problem with a lot of those is that they dont
offer a radius head/sensor... you will still get a
reading(in most cases) through the gel but it also
is reading the thickness of the gel

I bought my tester off eBay a couple of years ago 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 concave 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.

Brad

For what its worth, the cheap ones only read in mm's. I know it can be converted over, just letting people know