73SpeedBuggy
Well, after putting maybe 400 miles on my newly rebuilt engine, it locked up on me. I was screwing around in some gravel and the RPMS probably got a bit high when it happened.  I took it all apart and apparently the main bearing welded itself to the crankshaft.  Why would this happen?   Did I over-rev the engine and this is a natural effect of that?  Lack of oil?  I checked the reading on the dipstick after it happened and the oil level was fine. Does having an oil filter affect what the level should read on the dipstick? Why else wouldn't that bearing have been getting oil?   Before I fix everything I need to figure out why it happened in the first place. 

Now, as far as fixing it, is my crankshaft shot or should a machine shop be able to save it for me?  Also, when it locked up it stretched the little pocket for the dowel pin in the case.  does this mean I now need a new case as well? 
-Adam
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fatalifeaten
Odds are you've got a plugged oil galley passage and this prevented the bearing from getting enough oil. Combine that with some high rpms throwing the oil around and you have a winner! Time to toss the case in the crock pot (clean tank) and have it gone though and inspected. It might be a good idea to have it opened up for full flow at the same time. That way they can get into all the galleys with brushes and clean the gunk good. It'll cost a little bit more to do, but even an extra hundred bucks for machine shop work is cheaper than the rebuild you're looking at now. The machine shop should be able to inspect your crank too and tell you whether or not it's in need of love. Might have to have the mains ground if it galled the journal up badly enough, but they make oversized bearings for this exact reason. They also make oversized dowel pins that are stepped so that you can oern up that ovaled hole and still have the correct size for the bearing nub.

Did you build it or did you buy it from someone? If you bought it, I'd be on the phone with them lightening their backside by a pound or two. That's the kind of mistake an engine comes with a warranty for.

Daily Driven Dubz Phoenix AZ Family


'66 Deluxe
'63 Deluxe ragtop
'61 Deluxe
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olspeed
I would have to agree with fatalifeaten that it was probably a plugged oil passage. But one thing you did say- it was a newly rebuilt motor, did you do it or someone else. and whoever did it did they change out the oil cooler or at least back flush it. If the engine had a bearing failure to begin with and the oil cooler was reinstalled then that could be the cause of your contamination. VW oil coolers are built with lots of tiny passages up through the fins that can trap debris from an earlier bearing failure or just a careless oil change. This debris is almost impossible to clean out. It will then be released back in to the oil flow just a little at a time. You can back flush it as I have done once or twice before and have had some luck... but if you want to do it right it should be changed. On your crank you will most definitely need to get it to a machine shop and have them magnaflux it to see if it is cracked, because even a little heat can most definitely cause a problem.I would also have them check it for hardness also (I'm use to industrial diesel applications) as most forged cranks I have seen are up around 40 to 45 rockwell hardness and on the cast cranks we checked they were around 30 to 35 rockwell hardness. If it were to test out at around 25 or below on the rockwell scale I wouldn't use it. I did check my VW shop manual and there is no listing for hardness on a VW crankshaft in there but I know from experience with low HP diesels that a crank with that low of a hardness will not live. Also a lot of times that information is put in service bulletins for machine shop use and not in a shop manual.
Olspeed   
66 Ghia, "Dexter" 76 flat window Beetle
It's not a Car it's a VolksWagon!
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68autobug
 
yes, I agree it sounds like a blocked oil gallery..
or maybe semi blocked or the blockage happened at the time.
I couldn't see an engine running too long with a totally blocked oil gallery..
 
the other question: were you turning hard right or left at the time?
as sometimes there isn't any oil in the sump pickup at that time.. hence the reason to use an extra sump ...
 
but as said, the crankshaft can be cleaned up...
and a larger dowel fitted...
 
so, not a Large problem..
 
it can be fixed...
 
best of luck next time...
 
LEE
 

68AutoBug - helping keep air cooled Volkswagens alive in Australia & around the World -

http://community.webshots.com/user/vw68autobug
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73SpeedBuggy
Thanks everyone for your input.  I did the rebuild myself and thought I cleaned the engine out well, but it's definetely possible I missed something.  It's actually at the machine shop now.  He's going to see if the crankshaft can be saved and fix me up with one of the stepped dow pins. He also said my endplay might have been to tight causing the bearing to heat up.   After reading your input here I'm going to ask him if he can clean it up real nice for me as well. 

Also, I was turning hard left when it happened with the wheels spinnning loose in some gravel.
-Adam
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fatalifeaten
73SpeedBuggy wrote:
Thanks everyone for your input.  I did the rebuild myself and thought I cleaned the engine out well, but it's definetely possible I missed something.  It's actually at the machine shop now.  He's going to see if the crankshaft can be saved and fix me up with one of the stepped dow pins. He also said my endplay might have been to tight causing the bearing to heat up.   After reading your input here I'm going to ask him if he can clean it up real nice for me as well. 

Also, I was turning hard left when it happened with the wheels spinnning loose in some gravel.


Doh! I should have thought of end play. That'd absolutely do it. I doubt you breaking it loose in the gravel would have killed it, not that fast. In my experience you'd have floated the valves and hung one before you'd lock it up from that.

Do you have a dial indicator or an end play tool? If not, Get one. The end play tool will set you back a whopping 5 dollars-ish.  A good dial indicator will be in the 40 dollar range+ Buying both is still a fraction of what you're going to pay the machinist, and that's if you aren't buying new parts.
Daily Driven Dubz Phoenix AZ Family


'66 Deluxe
'63 Deluxe ragtop
'61 Deluxe
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olspeed
OK,thought I would bring up the oil cooler again especially since you have now had a bearing failure. At least try to back flush it with a good solvent (Stoddard solvent,nonflammable) anything even gasoline(DON"T SMOKE!) will work in a pinch. Or you could get a new one,as the old one will now be a source of contamination direct to the main bearings.There is no way to filter it unless you remote mount the cooler.
Olspeed
66 Ghia, "Dexter" 76 flat window Beetle
It's not a Car it's a VolksWagon!
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73SpeedBuggy

Thanks for the tip, I'll see if I can find a new or reconditioned cooler. 

-Adam
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