paulpearce wrote:The top end was rebuilt but the bottom end is Original beetle block with 60k although i had it line board duuring the build.
I'm confused by this. You say the bottom end's original with 60K, but you had it line bored... So, was the bottom end split or are you just going on hearsay about the line bore?
The description you've given is classic big-end failure – the first bearings to go on a VW engine as they are the last to get any oil. My suspicions are as follows:
If the block was line-bored, did you fit the correspondingly oversize bearings? If not, you'll get catastrophic loss in oil pressure.
Is the crank reground – if so, did you measure the journals to ensure they have been ground to the correct size? DO NOT take it for granted that all bearing journals have been ground to the same size! Measure to make sure…
The failure MUST be either big-end or (less likely) main bearings, and failure on a rebuilt engine will be point towards wrongly-sized journals and/or incorrect bearing clearances. Main bearing failure on a VW engine usually leads to complete seizure – big-end failure leads to knocking as you describe, followed by seizure if you keep it running. The rodbearing wil probably weld itself to the crank once the engine has stopped.
Assuming the case has been line-bored correctly, you may get away with a regrind of the crank, but will almost certainly need a new set of (matched) rods. Good luck.
