OS Piston Pin

[Bryan Kennedy]

Verne
 
I may be late, but when I changed mine, I tapped the crank out using a soft
wood piece before I heated the case and tapped the bearing out. for what it
is worth.
 
Sounds like you already have the crank and the bearing out together?
 
Bryan Kennedy
NSRCA 1744
AMA 1744

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On
Behalf Of Verne Koester
Sent: Wednesday, July 02, 2003 2:40 PM
To: discussion at nsrca.org
Subject: Re: OS Piston Pin


Eric,
Not at all like a lecture. Last night about 10:00, I would've paid good
money for it so I could fly today. Between the various responses, I was able
to realize what you just explained and got it off. Next comes the rear
bearing itself which is locked solidly onto the crank. Came out of the case
okay with a little help from my heat gun, but coming off the crank will be
another matter. I've been flying YS for so long now that I've forgotten how
to get through these little chores.
 
Thanks,
Verne

----- Original Message ----- 
From: Henderson,Eric <mailto:Eric.Henderson at gartner.com>  
To: discussion at nsrca.org 
Sent: Wednesday, July 02, 2003 9:32 AM
Subject: RE: OS Piston Pin

Verne,
          The OS 1.40 requires you to slide the conrod on the wrist-pin.
There is enough travel to then allow you to remove the big-end from the main
crank pin.
 
The problem is that the wrist-pin gets dirty either side of the conrod. This
prevents the conrod moving easily. I have had to reach in there with a
scraper before now. Most times a strip of cloth with Mineral Spirits can be
treaded around the wrist pin and then pulled back and forth to polish the
wrist pin in situ. Sometimes I have had to use Acetone as well.
 
To remove the rod I hook my pinky around the rod and pull it towards the
rear of the engine. It should move about 3/16".  It will then come off with
the crank near TDC. With the piston assembly removed I always polish the
writ pin for the next time. 
 
If you disassemble the piston assembly make sure you orient the rod the same
way that it came off. There is a chamfer at the front of the phosphor bronze
bearing.
 
(Hope this did not sound too much like a lecture?)
 
Regards,
 
Eric.
 
  
-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On
Behalf Of Verne Koester
Sent: Tuesday, July 01, 2003 11:29 PM
To: discussion at nsrca.org
Subject: Re: OS Piston Pin


Troy,
Thanks, I'll try it. Never thought it would work after seeing the groove
machined into the crankcase for connecting rod clearance.
 
Verne

----- Original Message ----- 
From: Troy  <mailto:troy_newman at msn.com> Newman 
To: discussion at nsrca.org 
Sent: Tuesday, July 01, 2003 11:07 PM
Subject: Re: OS Piston Pin

Don't have to remove the piston from the wrist pin to get the piston, and
con rod out for removal of the crank....Just takes a little patience....Its
not like a YS.....it will come apart....Try going to bottom dead center and
just slide the con rod back and off the crank pin....Viola its off....Goes
back together the same way. Its a little tough but things are sized to allow
for the removal of the piston and conrod as a unit. Just like a .46 or the
.61's
 
Its cake after the first time.
 
I doubt you will ever get the wrist pin out of the motor via the exhaust
port....But then again other guys have seemed to do some pretty weird stuff
with motors....
 
 

----- Original Message ----- 
From: Verne  <mailto:verne at twmi.rr.com> Koester 
To: NSRCA <mailto:discussion at nsrca.org>  
Sent: Tuesday, July 01, 2003 10:56 PM
Subject: OS Piston Pin

Anyone know how to get the piston pin out of an OS 1.4RX? Working through
the exhaust port, I got the circlip out but the pin seems to be stuck pretty
good. I thought I read where the id of the pin was threaded but it doesn't
SEEM like it is. Can't see in there real well but the id feels pretty
smooth. I want to replace the rear bearing before the Nats to avoid any
possible problems.
 
Thanks,
Verne

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