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Re: Trying to change a Piston with Engine and Crank in Place (TD)

Subject: Re: Trying to change a Piston with Engine and Crank in Place (TD)
From: Bob Howard <>
Date: Fri, 10 Dec 1999 20:14:28 -0500

On Fri, 10 Dec 1999 15:57:08 -0500 "Bob and Carolyn Grunau"
<> writes:
> Well here is another Bob to try to answer some of your questions.
> > 
> > Hi Bob,
> >   I am pretty certain that the piston went in from the bottom at 
> the factory,
> Yes, no other way to do it.
>  probably pre-connected to the rod. 
> MUST be pre-connected to the rod, upper pinch bolt must be torqued 
> to 33 to 34 ft-lbs or the top bolt will stretch and you have a danger
of rod
> breaking at the top. Never hold the rod while torquing the pinch bolt
> you will bend the rod.  Hold the wrist pin, two buttons in the wrist 
> pin holes and a vice are required before you torque the pinch bolt.
>  But, with the crankshaft in place you're going to have a very
difficult time getting a ring
> > compressor in there and getting the piston to enter the cylinder. 
You can fit the rings with a jubilee hose clamp or your fingers, not 
easy, but possible. 
> I gave up on the challenge, removed the piston from the rod and pushed 
> piston in from the top. 
> OK, but how did you connect the rod and tighten the upper rod bolt?

  The engine was on a stand, hence accessible at all points, else I don't
think it would ever have been done sucessfully. I pushed the piston in
from the top, using a regular ring compressor, slid it to the bottom of
the cylinder with the skirt out far enough for the pin to slip out of the
piston. Then placed the con rod, inserted the piston, put a piece of bar
stock through the piston pin to hold it, and torqued up with an unusual
thiin-wall socket. 
  I really admire your idea of the allen-head pinch bolt. It would have
been a lot easier to find four of them than to root around all over the
county searching for a socket wrench that would fit.


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