jw
Novice Class
Posts: 81
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posted November 16, 2001 07:26 PM
 Edited By: dougmeyer on 22 Jan 2002 09:04
Muzzy 81mm block question
Something I wanted to point out on the new nikasil coated aluminum block 11 engine. The top of the block checked out flat and the bores round, but the lower surface had over 5 thou's of variance when I checked it with a straight edge.
I called Muzzys and the guys (I called twice) answering the phone sort of blew it off. They seemed more concerned that I machined the case correctly (which by the way Muzzys very generously did for me for a fee).
Something I thought people should know.
I was also wondering if muzzy was enlarging the passages in the lower case to allow more oil to flow from the cam chain galley back to the oil pan.
john
  
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dougmeyer
Needs a job
moderated
Posts: 2713
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posted November 20, 2001 03:40 PM
Edited By: dougmeyer on 20 Nov 2001 15:45
Block tolerance
JW,
Was the bottom surface within .005" or was it .005" out of flatness? There is a difference. You could have high or low spots of .0025 without any sealing problems. One spot that was .005 high or low could cause a leak at the base gasket.
Or, are you saying that the block was .005" out of parallel top to bottom? That is the only condition that would concern me.
Regarding the drainback issue,the root of the problem is the fact that the sole area for oil return in a ZX-11 is down past the camchain, not the size of the holes below the main bearing in the lower case. Therefore we recommend external drainbacks from the head. We do such a mod. on request. Of course, enlarging those holes is something that can't hurt and something that I've always done on the engines I've built.
Doug
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It's not that I think you're dumb, it's just that so much of what you know isn't true....
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jw
Novice Class
Posts: 81
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posted November 21, 2001 06:25 AM
The lower part of the block was greater than .005" out of flatness primarily at the cam chain area measured longitudinally. Did not check for parallel.
Thanks for the info on the drainback holes and external lines. You are the Z master!
john
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