Sonic checkers

[waynebo]

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).

Thats what i said,,transducer is important to accurately measure a cylinder,,you must use a convex transducer too measure a concave cylinder,,,i beleive my cheap tester is very accurate i just need to get the proper transducer for cylinders,,,as i said its the tranducer not the material,,the unit is totally adjustable too compensate for material,any iron,any steel ,any material that can be tested......

 

[waynebo]

Good idea,,so you did this with the stock probe,,if so we maybe lucky as that even smaller i.d than a 4" cylinder,,which means a smaller radius.. now i wonder how the ruff rust scale that can be on the back side of a cylinder wall will effect the test,,some of it can be pretty dence and that might cause any tester to fluctuate,,of course practise will show how to deal with it,,wayne

 

[waynebo]

moper,,what have you found with rusty scale on cylinder back side? not a problem? wayne

 

[street demon]

I'll put the pipe outside will salt on it starting tonight but first I want to see what different temps will do. Here are two pics.

 

[moper]

The scale on the inside of the cooling jackets? It does make a difference. I try no to do a sonic test until the block has been thru the airless shot. It get's rid of the scale. Hot tanking/boiling doesnt even get all the sand out some times. What I find is it tends to test thicker. But that could also be part of the casing action too. Really, the areas that will crack are well above that seam. I test strting from the point where the readings go from way thick to what I would expect. That ends up in most blocks to be about 1-1.5" up from the bottom of the bore. The issues from the scale are below that usually, if I run into them at all. If the sonic test is the first thing you do, you will get more erroneous readings as opposed to after the main cleaning has been done. Typically guys want an answer before they spend any money to clean. I discourage that.

 

[waynebo]

S.Demon thats some awsome work there,,great idea..so it looks like the transducer will work on a cylinder?So you have access to a machine shop,,lucky dog..LOL

 

[street demon]

I build generator turbine combustion parts so I have acess to too many things. I think the tip will work fine but I did findout something interesrting. The readings from inside to outside vary...I forgot the exact number but it was around .030 I'll check tonight. Also there was a difference from flat to the pipe and again I'll double check that all tonight. Will a cylinder wall I think the tester will work just fine. I do have a 80's 360 block that I left in IL with my parents that I'll get back over here right after christmas and start cutting on.

 

[street demon]

OK just got back from IL and I cut out two pieces of cylinder walls from a 360. I calibrated the checker and the velocity came out to be 4360. I still have some more checking but that velocity was reading the walls within .010 or less. I checked 5 blocks out and was surprise to see how steady and consistent it read. The pieces I cut out had some nice white powdery build up on them. I cleaned it off and mic'ed it then calibrated the checker....I then measured some places without cleaning it then wrote the number down and marked the spot. After cleaning the whole piece I went back and mic'ed it in those spots and the white crud didn't effect the reading. Neither pieces had very much rust so I'm not sure what rust will do to the reading. Also the temp didn't make a difference. I warmed up the block to well above freezing then checked them and the next day I let them get below freezing and it still read very very close as to when the blocks were warm. I'll post more info after I do more testing.