jameighan

OS FT-300 ISSUE
Members,
I now own a OS FT-300 ( S/N approx. 3,500 ) that has very low run time, but has been stored for 15 plus years. It's very tight and may have to change the bearings. The rocker arms are very stiff and I have tried heat, WD40, and oil to loosen them up to no avail. I want to remove the rocker arms, but the rocker shaft will not budge. I did remove the set screw that locks the shaft in place, but I think the previous owner used fuel with some castor oil. The rocker arm area is very clean with no sign of rust. I'm holding back on making a fixture to hold the engine in place and utilizing my bench drill as a press and apply pressure to the rocker shaft along with heat from a heat gun. I don't want to overstress the engine head.

Does anybody know what the magic touch would be?

Jim Meighan

aspeed

Fuel works better than WD 40. Just dribble it everywhere and rock the shaft back and forth slowly till it loosens up. Use a prop and caution and heat if needed. I have never needed heat yet, but only have the one 4 stroke.

rrengineer

My Feedback: (3)

Put it in the oven at 250 for 15 to 20 minutes. It will loosen the castor oil up and you will be able to take it apart. After that fuel will loosen everything up, but clean it off and oil everything before putting it away again. Always use after run oil. Model engines like everything else don't like to sit for long periods of time..

jameighan

Guys,
Many thanks for your info. While I have applied heat to the head, I should have put it in a controlled environment and let it sit for a long period of time. I just don't want to apply a lot of force to the rocker shaft. I also tried MEK on the rocker arms and noted that it did help to somewhat, but still want to remove the rocker shaft to clean all surfaces.

Thanks for your info,
Jim Meighan

Cruisen

Hi guys. I am a new member, but I have been a modeler for 40 odd years. I have just started collecting a few older OS engines and I need a copy of the operating instructions, etc for a 1960s OS 19 RC. If anyone could help it would be much appreciated. Thanks, Cruisen.

jameighan

Members,
It gets down to the right tool for the job. This time I utilized a heat gun with a small nozzle that was designed for shrink fit tubing. The wrap-around nozzle fit over the rockers and applied enough localized heat to do the job. It still took a flat head punch with some light tapping, but it worked great. It was castor goo all the way. I'm sure that is also a problem with the bearings and I'm going to break it all down as required. I may be able to save the bearings if it is just castor oil goo. The solvent MEK will melt the castor away and after a few rinse cycles they may be OK.

One of the failures with the FT-300 was the connecting rods. I'm planning on installing a muffler tap pressure nipple between the inside and outer crankshaft bearings, just like the Enya VT-240 engine. This would allow for plenty of after run-in oil to lubricate the connecting rods. After oiling, the nipple would be capped off for normal running.

After this engine is back in shape, I have two Saito FA 270 T's that need the same treatment.

FYI,
Jim Meighan

Linkan2

Here comes a small video on us 200fs after I switch the spring on the exhaust valve.
to a harder spring the same as on the intake valve

Lars

the Wasp

My Feedback: (1)

hi guys, I hope you are not as cold as I am right now

can anyone tell me where I can buy OS parts (other than Towers) ?? I need a Back Plate Gasket for my 61FX and Towers does not have it.

thanks guys, stay warm !

Jim

Ernie Misner

You might try Advantage Hobby.

Prohack01

HI all, I recently did my first full tear down of a FS engine, its a fs70 alpha I picked up that had frozen valves. Original owner was running synthetic only oil fuel through it :-/ There was a lot of black carbon built up on in the head. Now that its clean I can only get the engine to start and run at half or full throttle. I am not sure if I have the valve clearance wrong (too tight?) or the cam one tooth off? Any ideas? I marked the cam to try and get it back to the correct spot, but as I said first time here, so maybe I make a mistake?

extra300crazy

The mark on the camshaft should be lined up with the pushrod tube instead of true verticle. The instruction manual for the 72a will tell you the starting point for the idle screw setting, which I think is to start with the needle flush with the housing and then 1 complete turn in. I am running all the alpha engines and love them. The valves should be set between .004 and .010. Hope this helps.
Karl

Ernie Misner

Hello Karl! Are you running castor in your 4-strokes? I wonder if the above poster's engine had no ARO in it when using the synthetic fuel. Thanks.

extra300crazy

Ernie,
I've been running O.S. 4-strokes for nearly 30 years. In the beginning I used a synthetic/castor blend and noticed a varnish build up and a lot of carbon. I switched to a 15%-18% synthetic blend and have used it ever since with good results. I run my engines completely dry at the end of each flying day. I fly at least a couple of times a week, so I just leave it at that. At the end of each season in addition to giving the engine a complete wipe down and adjusting the valves, I load it with ARO for the winter storage.
The engines that I have seen of my fellow club members that have frozen up, were run hard and put away wet for an extended time. One of my club members who runs Saito engines complained of valves that were badly carboned up from using a castor blend after rebuilding it. I put the ARO down the pushrod tubes while I have the valve covers off after adjusting the valves.
Hope this helps,
Karl

the Wasp

My Feedback: (1)

to add, there are a few fuel brands out there making what they call "Saito fuel", 20/20, no Castor

Ernie
thanks for the parts info !!
Jim

extra300crazy

Wasp,
I've heard that the YS 20/20 blend works great in the Saitos and have been thinking of giving it a try. Anyone have any experience with it that they can share with me?
Karl

the Wasp

My Feedback: (1)

YS 20/20, that's right

Ernie Misner

Thanks a bunch Karl! Much appreciated. I've been away for a while and it looks like synthetic is more accepted now. Well that's great because the castor is so messy anyway. Also thanks to The Wasp, Extra300Crazy and all. You guys are the best.

Hobbsy

My Feedback: (102)

My fuel,of choice for the last 15 years give a year or two one way or the other. 10% nitro methane, full synthetic. Neither you nor the engine will miss the castor.

extra300crazy

I would like to add that I've switched over from Coolpower 15%- 18% fuel to their Multi Viscocity (MV) fuel. It seems that with the different oils in the fuel, that my needle settings remain more constant regardless of ambient temperature.

I just learned that Hobbico has just filed for bankruptcy......... oh crap!
Karl

Prohack01

my engines seem to like fuel with some castor in it, not full syn. What are you guys using for ARO? I have been using 0-20 full syn for that as this didnt gum up over winter.

Hobbsy

My Feedback: (102)

I modified the pump on this Corrosion X pump bottle, I have about 18" of fuel line on it and can pump it directly on the crank case vent.

extra300crazy

I've been using an ARO that was made by Powermaster fuels, put down the push rod tubes when I check the vavle clearance at the end of the flying season. I've heard that Marvel Mystery Oil, auto trans oil, air tool oil etc works well also.
Karl

rcspec

My Feedback: (15)

The TH12x1A & B TurboHeaders are on sale!

Ernie Misner

Thanks Dave, that is really good to see! I have been away for a while and castor seemed to be the rule a while back....

blw

My Feedback: (3)

I would miss the castor. I trust my tuning but synthetic still burns to ash too easily for me to trust it without some castor protection. Just my thoughts about engine protection, etc. Castor has some downsides to it, but nothing I can't live with. At least we aren't having castor vs synthetic arguments anymore.