OS Max 20 Renovation - Pt 1: Dismantal & Clean - 1970's Glow Engine Restoration

[@doppelraab]

Before disassembling engines in this dirty state, I usually leave them immersed in diesel oil or kerosene for 48 hours, this makes the cleaning process much easier. Brgds, Marc

[@oscartravis5740]

Thank you so much for this! Clear and easy to follow and perfect for an absolute beginner like myself. I have the exact same engine needing a clean and de-gunk. I don't have an ultrasonic bath so I'm doing it all longhand 😊

[@MarkRobinson555]

Glad it was helpful, thank you for the comment 😀

[@royrobinson4059]

Thanks for that Mark you've done an amazing job on that engine, dad would have been over the moon seeing them up and running again 😊

[@MarkRobinson555]

Hi Roy, thanks for the engine, really appreciated

[@Camarc64]

Hi Mark, excellent video my friend, thanks by sharing with us !

[@MarkRobinson555]

Glad you enjoyed it, thanks for the comment

[@ronnieschaniel9927]

Hi, I have been in RC since 1978. I use K-1 Kerosene to soak in and brush with various brushes, and then use Navel Jelly with a dremel brush and the case cleans up very nicely

[@davidkenyon5444]

Thanks Mark, this is just the series I was hoping for!

[@MarkRobinson555]

Excellent, glad i helped, thanks for letting me know

[@Discopuss]

Jewelers "polish pads" worked great to clean up a crankshaft. I put the prop nut square in a cordless drill chuck, then screwed in the shaft, turned it slowly in the drill with gentle pressure and made quick work of the crank shaft polishing. I used the same setup to capture the cylinder liner to polish the outside.

[@MarkRobinson555]

Thanks for the info, appreciated 😀

[@keithfisk5641]

Your engine appears to be missing a flat spring steel shim washer that goes on the front of the crankshaft between the prop driver and the front of the crankcase. This is important if using an electric engine starter or a pusher propellor. Without it, excess wear will occur between the prop driver and the nose of the crankcase possibly resulting in the crankpin then rubbing against the back cover of the crankcase. On my OS 20 Max, which I bought new not long after these were first released on the market, the shim measures 0.17 mm thick. A superb wee engine although mine endured a lifetime at full throttle on control line planes and now is low on compression so doesn't run as sweetly as it used to.

[@MarkRobinson555]

Thanks for the comment, and your thoughts, its really appreciated

[@russcole5685]

You can get pinch clamps, sort of look like collet chucks. Remove and punch the sleeve near the top to create piston seal near TDC. That is if you're interested in rerunning the engine. This is what a lot of the car guys do to save buying new piston, sleeves.

[@SonAndDadFPV]

looks good... a friend of me who collected old RC motors always put the pieces in the dishwasher. lol

[@richardblackrcmaniac9545]

Fantastic work once again if you ever get one that is seized always place them in the oven for a few minutes it helps not rounding off the screws when they are too tight and also helps free at the bearings a bit too make it easier to strip the first engine I ever restored was exactly the same O.S. 20 as that inherited from my late uncle

[@MarkRobinson555]

Thanks very much appreciate the comment

[@biddlelove2135]

I've got an OS 20 in my mardave stockmaster, it revs well but when it's on the road with a bit of drag it goes sluggish, I'll have to make a rolling road, great video bud!

[@MarkRobinson555]

Thanks very much 😀

[@jmaclaren4147]

This relief you see, on the piston crown, is an auld free flight mod people used tae dae fae higher RPM reducing galling fae piston swelling. OS did this on the Max .30 an .35. as well. It's no ae ring, it's ae relief machined on th crown

[@richw0123]

The best thing I have found for cleaning old glow engines is Ethylene glycol found in green anti freeze. The parts can soak for a couple days and the ultrasonic will do the rest, the parts look like new.

[@MarkRobinson555]

Never tried it, but I will do at some point will be interested to see the results, thanks

[@californiadreamin8423]

@@MarkRobinson555 Hi Mark, very enjoyable video. I’m making a control line model approximately 70% copied from a model of my youth. It was originally fitted with an AM10 …no silencer…but I think I made it too heavy . I’m thinking of fitting an OS10, silenced, which is not that much heavier. Do you have any pointers to articles which explain the pros and cons of this type of engine change ? Thanks.

[@matthewdurkee5673]

I know this is an older video but i worry I have been getting my old engines running again the wrong way. I have just been brake cleaning the outside and WD40 in the inside. Then just heating it up to get it turning again. Once it turns i am able to start them right up . They sound good and gave great power. So hopefully i didn't damage them at all.

[@MarkRobinson555]

Sounds like you have done a great job, pleased they run well

[@terryblackman6217]

Good morning Mark. Thank you for another enjoyable video. After watching your video I took my engines out of storage and although I cleaned them at that time they also have built up a film on them. Nothing like the OS you have just cleaned. Could you please tell me where I can obtain the bottle of cleaning liquid you used. Terry

[@MarkRobinson555]

Hi Terry, thanks for the comment, really pleased you liked the video. Here is a link to the product I use www.amazon.co.uk/Seaclean2-Ultrasonic-cleaning-fluid-500ml/dp/B009HQ3R0S/ref=sr_1_5?keywords=seaclean+2+ultrasonic+cleaning+fluid&qid=1650542514&sr=8-5

[@terryblackman6217]

Thanks for that Mark. On order. 😊

[@lgmyt]

I also have one of those engines and I'm going to restore it following your explanations. Could you please let me know the measurements of this propeller?

[@MarkRobinson555]

Have you seen pt 2 and 3, I give full details in part 3 the test run, its a 9x5

[@lgmyt]

@@MarkRobinson555, thanks for answering me! I loved your videos. I haven't watched part 3 yet, but I will. Regarding the propeller, I thought it was 8x4. I'm going to buy this 9x5. I'm from Brazil and no one I know had ever seen this rarity of an engine, hence my difficulty in finding out which propeller was recommended. I got this engine about 10 years ago and it's been idle ever since. Does it still work? hahahaha

[@ronliebermann]

I love these old engines. But I’ve always wondered: is it possible to make a miniature rotary engine?

[@MarkRobinson555]

Yes I am sure it would be with the right tools and skill

[@Apexxshock]

OS used to make a rotary engine

[@Master_zzz]

This OS 20 has an compression ring. All of the OS 20 with a steel sleeve do.

[@MarkRobinson555]

This engine has no compression ring

[@Master_zzz]

@@MarkRobinson555 It has. Take a close look. You will find it. All of these OS .20 with a steel sleeve do.

[@johna.s.3847]

soak it in methanol alcohol to loosen up the caster.

[@rickr530]

A little kerosene and a nylon brush would clean that up significantly faster and more thoroughly than that ultrasonic cleaner.