OS Piston Pin

[Jeff Hughes]

Now you did it! you shoulda tapped the crank out first, then heated 
the case to get the bearing out. Since the bearing and the crank are 
both steel, they will expand fairly evenly with heat, so you may have 
to fabricate a gear puller to get the bearing off the crank.

> MessageBryan,
> Yup, the crank and bearing are out of the case. I tried tapping it 
out of the case w/o heat and it wasn't going to come out w/o some 
serious pounding so I heated the case w/my monocote heat gun and it 
came right out. Now the problem is getting the bearing off the crank. 
Never had one this tough before....
> 
> Verne
>   ----- Original Message ----- 
>   From: Bryan Kennedy 
>   To: discussion at nsrca.org 
>   Sent: Wednesday, July 02, 2003 2:40 PM
>   Subject: RE: OS Piston Pin
> 
> 
>   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 
>       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 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 Koester 
>           To: NSRCA 
>           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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