Re: 10 or 11 inch clutch

[bearbvd@domain.elided (Greg Hermann)]

>I checked into the flywheels when I was rebuilding my 392.  I called Mr.
>Scout in Eugene and Mike said he was positive they were the same.  I then
>had my engine balanced without any problems with a 304 flywheel.  It came
>with an 11 inch clutch factory and it has the bolt holes for a 12
>inch one.  If I remember right we discussed this on the digest about a
>month ago and we came to the same conclusion.
>Joel Webster
>On Thu, 22 Apr 1999, Greg Hermann wrote:
>
>> >You can also use a flywheel off of a 304 on your 345.  International
>> >flywheels are the same for the 304, 345, and 392.
>> >Joel Webster
>>
>> Careful about the mass of the bobweights--these are externally balanced
>> motors, and 304's, 345's, & 392's all have different stroke or piston
>> weights! So they may not all be the same, even thought they all will fit!!
>>
>> Greg

I'm sure no problems as long as you had it balanced. But I am still not
satisfied with the answer we got to on the list!

Particularly between the 345 and the 392--same stroke, same rods, but
different piston weights on account of 1/4" bigger bore for the 392! Either
the crank OR the flywheel and front pulley have GOT to be balanced
differently for these two motors (345/392) in order for the balance of both
TO_BE_RIGHT_!!! No two ways about it--and until somebody tells me where the
difference in bob weights is between the 345 and 392, I am skeptical of the
result of our discussion!!! Don't really care who said what, the above are
the physical facts of the matter--and there has got to be an answer
somewhere. And the 304 FRONT pulley is definitely different--no torsional
damper in it.

I have heard a bunch of stories about 392's with cracked cranks. Often
wondered if they resulted from mis-matched balance critical parts like we
are discussing here. Any future 392's I build, I will spend the extra money
to neutrally balance the flywheel and the front pulley, and put enough
"Mallory" metal slugs into the counterweights in the crank inside the
engine in order to balance it internally. Probably will also adapt a
"Fluidampr" intended for a BBC to the nose of its crank. These steps will
all work together to GREATLY reduce bending stresses in the crank, reduce
stress in the block, and increase bearing life substantially. Worth it to
me.

Been through this same stuff with RB Mopars too--on those--they changed the
weight of the con rods from the regular 440 to the 440 six-pack--and you
had best believe that the bob weights were different for the two motors!!!

V-8's are tricky about this, and getting them wrong puts a fair amount of
stress on the cranks and bearing webs in the block, not to mention giving
the whole vehicle a vibra-massage! What the extra vibration does to
starters and alternators, and other accessories attached rigidly to the
engine can also  be impressive and costly!

Just trying to save everybody a bunch of headaches here by presenting fully
proven technical facts--no offense or argument intended.

Regards, Greg
>>
>>