Artto Ilmanen

Hi Jon, If back at work - could you kindly check this, please?

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well, ”orders are orders” 🤗. Jon recommended the retaining compond so who am I to know better? It os a tight fit, though. You can’t push the bearing in with fingers

True! But if a frozen bearing and a heated crankcase, say 100 degree celcius: can you add the retaining compound if warm / cold parts? At least you don’t want to have a crazy hot crankcase to avoid burning your finger upon putting the glue on the bearing pocket..

Fortunately the bearing pocket is intact despite what ever happened. So I assume I should be good with just correct retaining compound and right tools & working method (bench press and support from below to avoid any risk of deforming the crankcase)

Thanks Ron, The link above (selection chart) suggest the 638 for “loose fitting parts” while the 2 other are for “close fitting parts”. But I suppose any of these could work.

Thanks Jon, this clarifies things. Funny thing is, basically most if not all Loctite stuff to hold bearings in place are green. Anyways, I suppose any retaining compound that holds the bearing in is fine as long as it withstands oil & fuel and works up to 150 degree celsius or so. I can’t find any Loctite 693 but instead a Loctite 603 might be the stuff you are referring to: https://www.henkel-adhesives.com/uk/en/product/retaining-compounds/loctite_6030.html https://cdn-e.soneparcanada.io/PIM_Docs/Docs/STEP_ASSETS_PDF/71628609.pdf

who knows what a previous owner had done? This is why I seldom buy any second hand engines. You never know that kind of ”maintenance” the engine has suffered from. These 2 come from friends who left the hobby. Fortunately the marks do not cause any issues.

Chris, You may be right. However, I’m not concerned about some leaks from the joints between the crankcase and the front housing or the back plate. My question is related to securing the pinion drive bearing to help with holding the bearing in its place. But also, using adhesive that permits any future bearing change.

..edit to my earlier post: I came accross some information claiming the Loctite 595 does not withstand oils or fuels? I wonder if this is false information? Or is there 2 different products with similar names? Anyways, I assume any adhesive silicone withstanding oil and fuel should do the job?

Ok, thanks for Jon's kind help I was able to dismantle my both 150s for bearing change. I first tried to remove the prop driver with a 2-claw puller: the result was tears in the eyes as the only thing I was able to achieve was to get some (yet small, fortunately) marks on the prop driver -> so next attempt was to press the crank with a quality press which did the job without any further hassle. I also pressed the pinion drives out with a press. Then I applied some heat to get the pinion drive bearings out - tjios helped and teh bearings came out very easily with just a tine help of a screwdriver and a very slight knock. Now the next phase will be to remove both front and rear bearings of the front housing. Jon must have some black magic trick to do the job easily but I plan to test to heat the front housing at 200°C and I hope this will help removing the bearings as aluminium is expected to expand more than the steel bearings. Let's see how things proceed. As I side note, on one of the crankcases there are fairly symmetrical marks (not quite, though) around the pinion drive bearing pocket? I wonder if they are a result of earlier bearing change or alternatively they could be some minor marks that came during the casting process? @Jon - Laser Engines I believe you said the other day Loctite 638 is the recommended adhesive to secure the pinion drive bearing? (small amount of it is recommended on the bearing pocket) You also said one could use Loctite 595 for the same job? The latter is more attractive as any future bearing change will be much easier with it as the Loctite 638 is a strong adhesive. So could I skip the Loctite 638 and go for the 595 or did I miss something?

Ok, I see. Thanks, Ron!

This adapter is an excellent product But how do you tighten it? As no socket head?

Thanks Alan, I will do so

Thanks Jon and Alan As a side note: this is my first warbird so all advice is greatly appreciated. Anyways, if I mount the engine with no thrust line angle, directly on the firewall in accordance with the lines marked on firewall the engine prop driver is way too high from the center of the cowling hole. About 1cm offset. So I need to do something on this

Gents, It seems that the thrust lines marked on the firewall of the model are way off. From what I have read this is not unusual with ESM / YT kits. Also, there is no right / down thrust angle built in the firewall. The manual does not say any thing on the matter? My general experience you need some down /right thrust angle. So, I have been thinking of applying 3° down and 3°right thrust angle. In order to find out the location of the engine mount drill holes in the firewall I plan to mount the cowling as straight as possible on the model by eyeballing it and then move the engine around to centralise it with the cowling hole. The engine is completely concealed inside the cowling so at least theoretically I should be able to carry out the process ( maybe I need to find a way to hold the model in vertical position) What do you think? Could the 3° down / right be in the ballpark of what is needed? Any other hints? Artto

Paul, this is crazy.. "a bit nippy at 22°C" 🤣 Some pictures from my club and one which was taken on the shore of Gulf Of Finland (frozen). At 51 I'm too old for winter flying - especially without gloves and starting glow engines, etc. I prefer tweaking my models inside and wait for warmer circumstances. But my buddies do love flying year around - to each their own.

I do have skis for my models but I'm too old for the fuss.. But, other outdoor activities in the nature are fine!

Sounds good. There has been lot of issues with Saito FG series engines although the FG90 is of newer design. Probably you will be happier with the Valach.

How is your flying season? I thought it's spring? And soon time to start a new flying season but obviously I'm wrong 😃. The picture is from my backyard, in Turku, South-Western Finland. Artto

Looks good, Nick! Too bad Laser doesn't do anything larger than a small 60cc, at least for the time being. Anyways, from what I have heard Valach engines are supposed to be of high quality. And it's a 4-stroke and not a chainsaw engine. Is the fan for added cooling, by the way?

Hi Nick, What engine are you planning for the model?

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Ok, I fixed the faulty air cylinder - I cleaned it out throughly. Then I installed a new 8,9mm X 1,9mm O-ring on the piston and lubed everything with CRC silicon grease. Now everything works as expected - no more leaks. Now that everything works time to learn how to reduce the cycle speed of the gear to have a system that is more realistic. thanks for everyone for great help! This is a great forum!

Gents, I must confess that I feel embarassed - I started to rethink on what Stu wrote about how the control valve should operate. So, it became obvious that I got fooled by thinking that the control valve was the culprit for the air leak of the system. I was wrong: as I retested the control valve in accordance with Stu's advice: voilà, no issues with the control valve! Instead, after testing the air cylinders individually by submerging them in water it became obvious one of the air cylinders were leaking air through the piston O-ring. As I dismantled the faulty cylinder I found a small aluminium particle that was sitting on the O-ring (quality control?), maybe causing the leak. This morning I shopped new O-rings of different sizes to test. I will clean out the cylinder throughly and apply new silicone grease. Logically thinking, this should fix the problem as i can not see any scratches on cylinder wall. I was also wondering wether to change the small O-ring that seals the piston axle (how do you call it?) at the same time but I skipped this idea as it is not leaking? How on earth can you even change it? (see picture). Also, I think it might be a good idea to replace the air tubing (which is 10+ years old) although it feens still soft and flexible. But, what size? The manual refers to "1,7mm" inside diameter. Hobbyking has this size but it's out of stock. Robart is 1,58mm (1/16 inch) and Festo seems to be 2,1mm. (There is also a "pressure reduction inlet" mentioned in the manual - I suspect this is used to reduce the airflow so the gear won't respond too agressively when the valve opens, hence maybe the inside diameter is not that sensitive) But how sensitive is the inside diameter actually is? Can I use any of the ones referred above? sorry again for many questions - I hope you do not mind