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This doesn't look right - crank journal
https://www.ausmini.com/forums/viewtopic.php?f=2&t=63523		 Page 1 of 1
Author:  VulcanBB18 [ Sun Jun 06, 2010 8:06 am ]
Post subject:  This doesn't look right - crank journal
Hi everyone,

Pulled down the "rebuilt" 998 I got with my van yesterday... apart from some doozies like all the piston-ring gaps being lined up (on every piston!) and heaps of gasket goo under the oil pump, the way the crank is ground has me concerned.

Image

You can see in the photo on the big-end, there is a lip were the 10 thou grind on the journal has stopped, no blending into the radius at all. The main bearing journal looks how I would expect it to look.

Image

That's another view, plus a mark on the No1 big-end from what I don't know. What's people's opinion on this crank, get another one or this one is okay?

The No1 big-end bearings have copped it somehow as well - remember this engine has never started or been attempted to start.

Image

Cheers

Jacob
Author:  drmini in aust [ Sun Jun 06, 2010 9:41 am ]
Post subject: 
That is BAD workmanship. Looks like a trip to a crank grinder you trust then. They would be able to clock the journal up and fix without grinding it to the next undersize.
Author:  Ian49 [ Sun Jun 06, 2010 12:29 pm ]
Post subject: 
It looks like the rod has hit the journal when the engine was being assembled. The damage has left a small projection on the surface of the journal which has damaged the bearing.
Author:  GT mowog [ Sun Jun 06, 2010 3:00 pm ]
Post subject: 
Very careless. It appears that the crank would be salvageable, but will need andother grind - done right.

Overall it sounds like very careless workmanship and poor assembly.

Check Everything.
Author:  norton [ Sun Jun 06, 2010 3:04 pm ]
Post subject: 
Ian49 wrote:
It looks like the rod has hit the journal when the engine was being assembled. The damage has left a small projection on the surface of the journal which has damaged the bearing.

prolly fitting the pistons with the crankpin up near top TDC
the highly skilled engine builder says to himself "hmm why wont these pistons slide in, maybe the ring compressor is a bit tight, easy fixed, FBH whack whack whack"
Author:  micowen [ Sun Jun 06, 2010 3:41 pm ]
Post subject: 
who did the rebuild?
Author:  VulcanBB18 [ Sun Jun 06, 2010 4:35 pm ]
Post subject: 
Thanks for the comments everyone.

Micowen - the guy I bought the van shell off apparently did the engine rebuild - must have farmed out the machining and did the assembly himself. I would have been one hell of an engine if I'd tried to start it, with that bottom end and all the piston ring gaps lined up...

Ok so as it looks I'll need to head off to the machinist anyway (gotta find a good local one, haven't needed one for 10 years!) I'll get the spare 998 cranks out of the cupboard and see which one looks best for a clean up and grind.

Worth getting a 998 crank crack tested? I must admit I've never heard of one failing!

cheers

Jacob
Author:  GT mowog [ Sun Jun 06, 2010 5:48 pm ]
Post subject: 
VulcanBB18 wrote:

Worth getting a 998 crank crack tested? I must admit I've never heard of one failing!

cheers

Jacob


Well for the few dolla's that it costs and the possible consequences of failure, get it tested.
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