Sonic checkers

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street demon

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I went to sonic check some blocks last weekend and couldn't get stable readings. What brand do you guys use and what is the tip diameter? Also what do you use to calibrate it? Any other tips or trick would be a big help. Thanks
 
What kind of readings were you getting, and what do you think stable is, there may be a difference of .060 - .090 in the same cylinder, due to core shift and who made the casting.
 
Unstable meaning holding the tip in the same place and the readings were jumping .030-.060. I couldn't get it to stay the same for more then a split second. I think my tip is too big but I want to be sure before I buy a smaller one. My tip size is .420
 
Yes I was using a clear coupling gel made for it. I pressed down and tilted it back and forth to get set in the middle and the display just kept jumping. I was getting different sweep readings like some were .15-.19 and .17-.21 but I'm not sure if the thickness of the actual cylinder wall was even falling into those ranges.
 
I just bought a ultrasonic tester myself and it appears i'm going to have to buy a transducer/probe designed for cylinder or pipe inside measurement because the flat probe can't give an accurate reading in a curved cylinder..
You could probally remove the freeze plugs and measure from the outside of the cylinder inward through the hole,,but it limits the area you can measure to just that area..but it may be enough to give you an idea as to whether or not you can bore the engine over..
 
I just bought my own because some people at work were starting to look like rats and didn't want to chance. The transducer tips are pretty expensive. I'm heading to the junk yard this week and grabbing a block to hack up. I'm cutting the cylinderwalls out of it so that way I can calibrate it perfectly.
 
thats what i've been thinking about doing also,,i have and old engine block on my disk for weight to help it cut better,,anyway it fix'in to loose a cylinder,,lol
 
What kind is yours? How much did you pay for it? I got a deal on mine but it's not as high quality but I'm not paying 2500 for one either.
 
I have a Dakota Ultrasonics PR-82. Most 1/2" trasducers are designed for a 4" diameter hole. If it cannot stabilize, the tester is probably not very good. I see the range doesnt even get finer than .059". That's about as accurate as setting spark plug gaps with a ruler. Also, having the ability to calibrate for the exact material is crutial. If you simply use a chart sayin "Iron is 600Hz" than you're already so far out of whack that the reading doesnt reall yamtter. Because every iron is different. I dn find the surface cannot have any rust or paint, and if there is material (like chalk in teh cooling jackets low down) it will play havoc with readings. Not being unstable, but difficult to repeat because the materials are tughing, but not the same frequency. Like checking an alumionum block with steel sleeves... ost testers cannot differentiate and therefore the results are usless. This is not a personal attack, so try not to get offended, but cheap sonic testers and operators who really dont know how to use them make for cheap testing fees and below average results. I personally know of several blocks tested locally that passed, and then promptly split after the engines were run for under 300 miles. There's a reason guys and equipment have to be certified to earn money testing pipes and things... If your tester didn't come with a certification, the results may not be very accurate.
 
Thanks for the input. I'm still learning how to use one but not going to give up yet. I figure that if I have 6-7 pieces of different thicknesses of cylinder walls then I should be able to get it calibrated right. The very expensive tester that I was using was from work. On even has a tv screen that shows a graph with the peaks and I don't pretend to know how that works. The others were not as expense but get sent out to get certified every year. The one I'm using is now mine own that I bought for cheap. The readings were very steady but it's not calibrated to cylinder bores. I will calibrate it using the velocity...moving it up or down until I get it reading right then try a few more pieces and see if it's reading right. It only reads correct from 0-50c so that stinks but what can you do. If it all works I think it will be a great tool and save me alot of money and run around time checking up to 10 blocks before I get want I want. Thanks again for you input.
 
Actually for what were doing i think it a great unit,,i have tested everything with micrometers and it is within .001" most of the time,,so i'm very confident in the unit,,i just need to calibrated to cylinder wall which it reads well,,i just need to verify and calibrate from there,,i'm a happy camper with my unit for picking the better blocks,,wayne
 
It's not the shape, but the material that makes issues. Think of it like taking a step into a pond. If the waters clear, you can see what you're doing. If the waters muddy, it could be 3", or 1' deep. The better testers can adjust for the clarity, and give you a good reading. The poorer testers can tell you its wet :) . If you're happy with the results, that's all that matters. I looked at a couple, talked to a guy or two, and i wasn't comfortable enough.
 
quote[It's not the shape, but the material that makes issues.]

So a flat probe on a round cylinder doesn't matter..i dont see how it can give an accurate reading if its not touching the cylinder except on the edge of the probe/transducer,,it can't.. a transducer has to have good contact with the surface to be accurate,,its not the material i'm talking about its the shape of the cylinder,,wayne
 
cylinder shaped like this ( and transducer shaped like this l do not go together,,but you can buy transducers for cylinders with various rounded faces,,i need one for 4" cylinders,,but i maybe able to take a piece of cylinder and test and see if its possible reliably test with given known error for the cylinder shape,,i doubt it will be accurate enough though,, (l <-no good
 
I've called GE several times trying to get some help with it(different checker, not the one I bought) and they want to built a tip just for my application. I've left 2 messages for the guy that builds them and still no reply. I'll try again monday. Also this one was over 2k and it's a DM4 made by Krautkramer Branson.
 
Looks like it. Let me know what you find out. I sent omni an email which is who makes both of our testers. I hope to hear something back but if not I'll call the US office monday. I also have two other tips but on is the same size as the one that can with the tester. The other has a rectangle tip which measures .240 wide by .365 long. It's 5MHz like the tester but it uses a coax type connector. If I can't get mine to read right I'll start cutting and splicing.
 
Wayne, transducer should be radiused to test a concave surface. Mine is. It is not very good on flat surfaces, like straight port walls, or decks. But I dont test there. They make flat, much smaller transducers for that stuff. It's only 1/2" in diameter, but it's radiased for a 4" ID. It's designed for a 4" bore, and the actual " metal things" (highly technical jargon) that send the signals are embedded in ceramic. As long as they touch the surface, it will read acurrate. It doesnt matter (so they tell me) if they sit perfectly fluch to the surface. But they need to be in contact directly with it. The gell fills in the surface features in the machined or cast surface. It's not meant to span distnace. Just provide a neutral "evening substrate" that wont change the reading, or effect the sund waves before they hit the metal. Remember machined metal looks and feels flat, but isnt. So this 4" radius test fine on under 4" (I' ve done 318s (3.91) with good results, and it will work on larger bores (I've done .030 over 400s at 4.385).
 
Ok I did some more testing to day at work. I took a 3.375 ID pipe with .250 thick walls and hit it with hammer just enought to oval it very slightly. Then I turned it down smooth on a lathe. I also turned it down so it would have steps in it. The thicknesses ranged from .185-.112 which I used a point mic to measure then calibrated my tester to it. The readings were very stable....I calibrated it to the middle step and it was reading .003 low on the thicker parts and .008 on the thin side. I was alittle disappoint but tried something I've read. I turned the tip to where it was side ways in the pipe and the reading got alot better. .001 on the high side and .002 on the low side. I'm very satified with the readings. I will post a pic after I get off work. My next step will be to put salt on the outside of the pipe and let it rust up outside and see what happens then.
 
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