cptgrady Posted May 13, 2017 Share Posted May 13, 2017 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. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted May 13, 2017 Share Posted May 13, 2017 !!!! Ye Gods! Broken woodruff key, I take it ? Mo Quote Link to comment Share on other sites More sharing options...
cptgrady Posted May 18, 2017 Author Share Posted May 18, 2017 Actually the key was still in decent shape. It must be much harder than the gear metal. Quote Link to comment Share on other sites More sharing options...
reb78 Posted May 18, 2017 Share Posted May 18, 2017 Thats so square it almost looks machined! Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted May 20, 2017 Share Posted May 20, 2017 On 2017-5-18 at 8:15 AM, reb78 said: Thats so square it almost looks machined! Which is practically impossible to do! 1 Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted May 20, 2017 Share Posted May 20, 2017 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? Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted May 20, 2017 Share Posted May 20, 2017 The way you'd machine a shape like that would be through EDM which stands for Electro Discharge Machining, also known as spark erosion. Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted May 21, 2017 Share Posted May 21, 2017 "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 Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted May 21, 2017 Share Posted May 21, 2017 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 ...... Quote Link to comment Share on other sites More sharing options...
mmgemini Posted May 22, 2017 Share Posted May 22, 2017 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. Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted May 22, 2017 Share Posted May 22, 2017 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. Quote Link to comment Share on other sites More sharing options...
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