ZERO connecting rod play?

[jester@westfailure.net (jester@westfailure.net)]

On Fri, 17 May 2002, Robbie Cotner wrote:

> I found that rods 2, 3, and 4 have a
> little bit of back and forth wiggle left in them after torquing, but the
> #1 rod is absolutely solid, it will not wiggle in any direction. 
This is not right.

When one assembles rods to the crank, with the crank outside the engine,
when torqued & with assembly lube, imagien that the crank is laying there
and the rods point out to the sides, if you lift one up off the table it
should be smooth, if you drop it it should slowly go back down.

This is kind of a poor-mans test to see if clearnace is right... but if
its solid & cant be easily & smoothly moved by hand, something is wrong.

Generally, it is considered good practice to pre-assemble the crank and
rods outside the engine to check all these things (clearance etc.), then
you can drop it in like that, or take it apart & put it back together in
the block if you didnt use stretch rod bolts. Thats just the way i
learned, can't say if its right or wrong.

The bearing shells have locating tabs, and if it slipped before you
torqued it it could have squished into the crank (the bearing would 
be shot. After rotating the engine your #1 rod bearing is probably now
shot, but fortunately the rod bearings are the cheapest ones.

the crank is too hard to be affected by this unless you run it till it
siezes, heh. Even then i built one aircooled engine that siezed within 200
miles with a new crank. the bearings were destroyed but the crank looked
100% That was a main though, i've seen rod bearing shells welded to cranks
from the heat of a bad bearing, so best not to take chances & check and
double check until you are sure the clearance is right. Maybe in this case
an investment in a plastigage to check your tolerances wouldn't be a bad
idea.

take care,

Steve

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