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cptgrady    0

After my 300 TDI wouldn't stay timed I opened up the case and stared at it for a long time.  After a while I realized the crankshaft timing gear wasn't quite aligned with the outer woodruff key cutout.  After pretty much destroying my gear puller and 8 M5 bolts I was able to get it off.  Make sure you use a hammer and chisel to knock it back in line before going after it with a puller.  I replaced it with what I think is a higher quality gear and put the crank pulley bolt on good and tight.  Now she is right as rain.  

IMG_1767.jpg

IMG_1757.jpg

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Mo Murphy    186

!!!! Ye Gods! Broken woodruff key, I take it ?

Mo

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cptgrady    0

Actually the key was still in decent shape. It must be much harder than the gear metal.  

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reb78    140

Thats so square it almost looks machined!

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On 2017-5-18 at 8:15 AM, reb78 said:

Thats so square it almost looks machined!

Which is practically impossible to do!

  • Like 1

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GW8IZR    75

The only way I can think of to machine that would be with a setup almost identical to the crank and key and use a reciprocating drive

Its fascinating to see wear like that and probably gives an insight into the load when in use. Do you reckon the material was softer or blemished on one side of the key slot?

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The way you'd machine a shape like that would be through EDM which stands for Electro Discharge Machining, also known as spark erosion.

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Troll Hunter    45

"The only way I can think of to machine that would be with a setup almost identical to the crank and key and use a reciprocating drive

Its fascinating to see wear like that and probably gives an insight into the load when in use. Do you reckon the material was softer or blemished on one side of the key slot?"

OK, all you techno forbes, what are they saying?

Mike

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GW8IZR    75
6 hours ago, Troll Hunter said:

 

OK, all you techno forbes, what are they saying?

Mike

OK to put it into terms I'd normally use then ;-)

Blimey thats a mess, I wonder why it went like that ......

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mmgemini    33
19 hours ago, GW8IZR said:

OK to put it into terms I'd normally use then ;-)

Blimey thats a mess, I wonder why it went like that ......

It went like that because the gear wasn't fully tight on the crankshaft. A normal 300Tdi thing. 

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GW8IZR    75
3 hours ago, mmgemini said:

It went like that because the gear wasn't fully tight on the crankshaft. A normal 300Tdi thing. 

 

I did know that ;-)

 

On 20/05/2017 at 11:13 PM, vulcan bomber said:

The way you'd machine a shape like that would be through EDM which stands for Electro Discharge Machining, also known as spark erosion.

So I had to make a similar piece, a control coupling for a valve but the slot had to run both ways from the keyway. I machined it slightly oversize but the correct dimensions either side of the keyway, then used a ceramic slug to fill the void which allowed me to close off the ends with TIG. Once both ends were filled the ceramic was removed with a punch and dustpan/brush. Then cut the keyway and line bored to size after the event. Of course the TIG fill was very hard to machine to size and took for ever on my tiny lathe but it worked out in the end. I didn't think the keway was going to cut but it did in the end after what felt like a million passes. Thankfully it was only 50mm long.

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