In article <950930165811_113262911@mail04.mail.aol.com>, S1500@aol.com wrote:
> Although there is evidence of some bearing wear, I don't see anything
> shocking. The 'little end' con rod bearings seem fine. What *does* seem
> a little strange is that the con rod is able to slide back and forth about
> 1/8 inch along the gudgeon pin. I can't find a spec for this. I'm guessing
> what stops the rod from slapping the piston in this manner is that the rod
> is held in place by the 'big end' bearing.
No need to be concerned, this is exactly as it should be, and your
assumption is correct. What you should be worried about, is radial slack.
Little end wear is normally not a trouble spot on these engines, so my
guess is that it is OK.
What you *should* be worried about, is big end radial wear.
"Death rattle" is caused by big end bearing radial slack, for which
the tolerances are pretty tight.
Since you will be replacing the crank anyway, ensure that the big ends
of the new crank are within tolerances. A micrometer must be used for
checking those, and the figures are in the book. Always measure at
different angles, to check for ovality. Have it reground if
outside spec., or if the bearing surfaces seem scored or damaged in
any way. (Regrinding will often be required for a S/H crank found on the
boneyard).
Again, don't think about axial slack in the big end bearings, that is
exactly as it should be, and no reason for concern.
Axial slack is only to be considered with regards to the crank shaft
thrust bearings, where oversize bearings may be required to compensate
for wear.
> I have no intention of re-assembling this motor. I will be repeating this
> exercise soon with another motor I want to run. Is there any point in
> saving parts like pistons, or the cam to use in another motor?
If the pistons are old and tacky, you probably should get new ones anyway.
Check the wear of the bore, and have them rebored if outside spec (these
engines are quite good with regards to bore wear). Always hone the
bores before installing new piston rings.
Five general hints on engine assembly:
1. Ensure that ALL oilways are open and free of dirt. On
receiving a reground cam, for instance, DO NOT expect that
the shop has done this for you!
2. Accuracy. Use a torque wrench for all critical bolts.
3. Cleanliness.
4. Cleanliness.
5. Cleanliness.
Egil
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Email: egilk@oslonett.no Voice: +47 22523641/92022780 Fax: +47 22525899
Snail: Egil Kvaleberg, Husebybakken 14A, 0379 Oslo, Norway
URL: http://www.oslonett.no/home/egilk/
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