Oberst

I have a question that I really need to have answered:

I had to replace the tappet screws on my 1984 O.S.120FS (Before Surpass) (Looks like a Saito) because it was worn and I couldn't get the allen to bite anymore when I tried to adjust the valves. The rocker arms has a paper washer or very thin nylon washer between the rocker arm and casing that the rocker shaft went through. I ripped the washer no matter how careful I was because it was very old and thin. I looked everywhere on-line for the paper or very thin nylon washers and couldn't find one anywhere. Is it really needed? And if it is important, where can I find the set of those washers?





Pete

Oberst

I'll try the Engine Forum, might get a answer there.


Pete

Avaiojet

Your local HDWE store will have a large selection of these washers. You could buy thin brass sheets and make your own.

Drill the hole first then cut the outline.

You could remove another to see what they are really made of.

I don't think it's paper?

Certainly there must be enough dead engines of that brand in boxes in modelers hobby areas. You might get lucky and your Thread my get seen by one.

Hope this helps.

Oberst

Thanks for your answer. I have the broken one in my hand I think it might be teflon or nylon. It's white and very thin. And you're right, it's not paper. The size of the Teflon washer is about 8mm in the outer diameter- and 4mm in the inner diameter. And like I said, it's very thin. So thin it's about regular paper thickness. I'm not sure what its for, I'm guessing it acts like a bearing between the camshaft arm and the inner side of the head.


Pete

deadstickdan

My Feedback: (3)

Oberst,

You may want to try contacting this ebay seller. If you read the description he includes rocker arm shims with the Buy It Now price. The auction is closed but it was not that long ago and he may be able to help you.

http://cgi.ebay.com/OS-FS-120-Model-...d=247438674552

Dan

Gray Beard

My Feedback: (-1)

Go into OS support and ask Bill if you even need them. I have a very old 1.20 and I don't recall seeing them.

Oberst

Yes it only seems that this model engine is the only one that has it, and the old engines don't have a blow up of the parts anywhere. I sent Bill a E-mail yesterday and haven't heard from him yet. I guess he's looking into it.


Yes Dan, I just might buy that engine. It's still in Auction.


Pete

Oberst

Ok I just got off the phone with Pauls Model Supply and he knew my engine well. He said that they are only used for shims to keep the rocker arms centered, they were not used for any other reason. He said a thin teflon, nylon or brass thin washer will work. He also stated that my engine was the only model that used them. All others didn't have that shim. O.S. Support didn't know anything because most of them weren't around the hobby way back then and didn't have a clue what I was asking them.


Classic R/C engines is a hobby all by itself!


Pete

Gray Beard

My Feedback: (-1)

Sort of like looking for parts for the old pumpers. I have a few engines that parts are getting hard to find. I try to buy from name brand places so I don't have a lot of problems. RCS sold out and the new place doesn't have anyting for some engines other then what came during the buy out. As soon as I bought my Brisons they sort of moved on too. I can see it if the engines were cheap but I bought some high end products, just at the wrong time.

Oberst

I agree, what you wrote is so true.

Well I bought a couple of brass washers from my hardware store and sanded and polished down the washers to about .001 thickness equal to my feeler gauge. When I put them in I made sure that there was no play side to side, and made sure the rocker arms could move freely.

It's only my opinion and I could be wrong- but it was dumb for O.S. to use teflon washers because they wear quite quickly with the heat and friction. Brass works like a bearing and works well with lubrication from the glow fuel.

Just to let you all know, I started up the engine at a rich setting and then adjusted the low end, midrange and top end yesterday. It all seemed to work fine however when I tilted the nose of the plane up, it would conk out on me. But every time I put the glow starter on and turned the prop she'd start right up and work fine, but then when I moved the throttle up she was unpredictabe. She'd run rough one moment then conk out, then when I restarted the engine she would run fine.

I spent hours trying to make it richer or leaner and get the good spot! It was very touchy.

I called my buddy at my club who trained me how to fly and been in the hobby since the 70's and he told me to take the carb apart and check the gaskets, wear and tear, and old gunk- then work my way to the lines and glow sump. He basicly reaffirmed my suspicion.

I took the carb out and apart. Not only the carb was all gunked and gummed up, the carb barrel had very loose tolerence in the carb body. I could literally move it side to side! Now I know where the air was coming in.

I looked up the the complete carb and what do you know, Tower sells it for $68.00! So your right Greybeard, it's best when you buy a old clasic that we stick to the name brands. We have a better chance for finding parts. And in the meantime, I'll keep buying more of the same used engine when ever I find it on Ebay or swap meets just so I'll have parts in supply.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCA48

Last thing I want to add is I bought got the engine with that Fokker I rebuilt. It's always the risk we take when we buy old engines. The owners will tell you they run good, but when we get them home our odds that it does run good are not always in out favor. JMHO

Thank you all, I figured I'd share the info.

Pete