Paying attention to the condition of your "tools"

Date 06-09-2008 22:26

Hello everyone, the automotive department at our college received some donations of equipment from another area college, they received numerous engine stands and some other peripheral items. Apparently the automotive instructors from our college didn't pay very close attention to the condition of these or just didn't recognize the signs that could signal failure. Some of their students were working on a Chevy 454 and while the engine was hanging on this stand it had a catastrophic failure, to compound the issue the college president was touring the shop at the time and witnessed this engine falling from it's mounting plate on the stand. I thought some of you might appreciate the photos that I have included of the condition of this. Our students have made the necessary repairs to it along with a change in the engineering of the connection point to better serve the purpose and done a dye/penetrant inspection of their work to insure that it doesn't fail again. This example also illustrates some of the issues related to using GMAW without using the proper parameters. It was definitely evident that these parts were joined in the short-arc mode as opposed to coming closer to spray transfer. Regards, Allan

By 522029

Date 06-10-2008 00:28

Bad design and bad welding!! And I bet somebody, somewhere, said: "See, I told ya mig would'nt penetrate"..

If you look at the uh, bead, you can tell that whoever glued this together was "stitching" like they were stick welding.

My two cents.

Griff

By aevald

Date 06-10-2008 00:50

Hello Griff, I completely agree with your first two statements, regarding the latter one, the folks that designed and welded this weren't there to see it fail. When our students did the repair on this, the first thing they did was replace the "pipe" with heavy wall seamless tubing, the next thing they did was burn a hole through the plate, then they bevelled the end of the tube, ground a weld prep on the plate where the tube passed through it and then groove-welded the flush side and fillet welded the other side. As I mentioned before, once the welding was completed they die checked their welds to insure that they didn't have any spots where there wasn't complete fusion. Best regards, Allan

By 522029

Date 06-10-2008 13:55

Sounds good!!!

Griff

By Tommyjoking (****)

Date 06-16-2008 13:56

prime example of "oh yea he can weld good", "It'll hold", "good enough", "looks good holds good". Hope nobody got hurt, a friggin 454 is heavy!

At least the auto students won't have to worry with a repair you oversaw Allen!

By sbcmweb (****)

Date 06-19-2008 02:05

Someone's really lucky that they didn't get their foot smashed when that block fell. Your repair was probably the best thing that could have been done to it, Allen. Especially going all the way thru, for two weld surfaces & assured penetration. I missed the process you used, if you mentioned it. I bet it'll be holding up motors after the Pyramids fall over :-). A good learning experience for your students, first hand. Just good no one got hurt to make that point! S.W.

By aevald

Date 06-19-2008 06:03

Hello Steve, they did make the repair with the GMAW process and 75/25 shielding gas, they were running .035 ER70S6 at roughly 25 volts and somewhere around 210 amps I believe. They did have the opportunity to have a close look at the problems with the original weld and we had a pretty thorough discussion about why it failed. I don't believe their repair will fail though. Best regards, Allan

By sbcmweb (****)

Date 06-19-2008 12:36

I don't think it will fail either. GMAW is excellent for a lot of repairs like this. As you had mentioned earlier, it's the parameters & prep that make the difference. None was done, or taken into consideration when it was made, hence the failure. You have some lucky students Allen. If they ever doubt it, just have them take a look here. I doubt that's the case though! :-) Thanks!! Steve

"Release the Craken!" (Zeus to Posideon, Clash Of The Titans)

By Bob Garner (***)

Date 06-16-2008 17:53

Excellant post!

What happened to the 454?

Bob G.

By aevald

Date 06-16-2008 18:10

Hello Bob, it did suffer some minor damage to some of the bolt-on items such as the alternator and power-steering pump, and a slight dent in the pan, but fortunately not anything too major that couldn't be readily rectified. Best regards, Allan