Re: Crankbolt - loosening & tightening

["Graydon D. Stuckey" <graydon@apollo.gmi.edu>]

On 2 Oct 1996 paul.heneghan@bbc.co.uk wrote:

> Have you tried Graydon's technique of . . .
> "It's a lot safer, cheaper and easier to stuff about four feet of a nylon 
> rope in the number one cylinder when its at BDC, and crank on the big 
> bolt.  Works every time for me."
> 
> I would be afraid of blowing the head gasket.

Geepers, some things can come back to haunt you!  That was a long time 
ago! :-)  

	Seriously though, I am trying to think of a reason why not to use
a rope.  The hint was given to me by another very good mechanic. 

	-Combustion pressures produce enough force to produce the rated
output plus friction and other losses.  Each cylinder would be 
approximately 1/5 of the total output.  My gut feeling is that this is 
approximately the force that you would exert on the piston by cranking on 
that crank pulley bolt.  I will check my engine design texts tonight if I 
don't forget.  The simple way is to start with teh BMEP (brake mean 
effective pressure) for a rough estimate of the force that the piston 
sees under normal use.  I just don't remember what this number usually 
works out to for this type of engine.

Later, ---------------------------------------------------------- 
Graydon D. Stuckey 	'85 Mazda RX7 GS, no toys 
graydon@apollo.gmi.edu 	'86 Audi 5000 CS Turbo Quattro, has toys
Flint, Michigan USA	'89 Thunderbird SC, lotsa toys