RE: OS140 Troubles
 

OK, Ive got the engine apart. (after a break for some slope combat) Thanks for all the tips, made it lots easier.

Should I be replacing the front bearing as well ? Its a sealed bearing and seems very smooth, as does the main bearing but I can see light surface rust on the rear face of the bearing. BUT as I mentioned earlier, there definately was noise as I turned it over when it was hot.
Seeing as I have it apart Ill replace it now, saves a job later on, which sounds as though may be more difficult after many hours of use with the crud build up.

If I should replace the front one now, how do I get it out ?

RE: OS140 Troubles
 

To be honest, I have never needed to change a front bearing. The only important thing is that you don't use the stock OS rear bearing when you install a new rear bearing. Get a bearing from the OS 140 EFI. It is sealed, and will last indefinitely. If you use the cheap stock OS bearing, you will be back taking the motor apart again very soon.(< 100 flights). I have yet to hear of someone needing to change out an EFI rear bearing. BTW once you get this motor adjusted, you will be very happy. My #1 OS 140 has well over 300 flights on it, (250+ w/EFI bearing) and has never let me down or deadsticked. At the most you might need 1 click on the needle if there is a large temp change from day to day. Stick with it, and you will be very happy.

RE: OS140 Troubles
 

OK.

Bearings. Stainless Steel, sealed or not sealed, rubber sealed or metal sealed ? ? ?

Apparently the NTN 6904 LLU is rubber sealed but NOT stainless steel. I got a 6904 Rubber sealed bearing from the local guy for $12.00, but its not stainless.

The bearing guys thought a Stainless non sealed bearing would be the best as it will get fresh lube and not rust, but if a seal is needed, leave the seal on the side away from the crank.

Does anyone happen to have the part number from an OS EIF sealed bearing, not the OS part number but a number/lettering on the actual bearing. 6904 is the size I know but what else is on it.

RE: OS140 Troubles
 

Lancair,

My advice is to follow the recomendation of David Gibbs. I fly with David and he is "a knower of many things".
Get the NTN bearings, leave the seals on both sides both bearings. The NTNs last as long as the SS bearings and are half the price, $12 ($9US) well spent!
The 140Rx is a great engine but it does have a small rear bearing. It is a fact of life that it needs regular service in that area (50-300 flights). With care, the odd ring and several bearings they will last 3000 flights and still be going strong.
As David said heat is critical. The underside of the motor needs air ducted to it and the holes for air to get out of the engine bay/pipe tunnel need to be 4 times the size of the inlets. (cos air expands when heated!) If the engine ran OK at home with engine cowl off but wouldn't run well at the field with cowl on that could be a hint......
Oil content also acts as a coolant. Personally I wouldn't run less than 17% oil, 20% in a new engine and in hot conditions. There is a penalty in idle but heat kills engines.
I fly a Cyclone with 140Rx and I have large slots in the fuselage/pipe tunnel to keep the air flowing. I also have a "bonnet scoop" to direct air to the rear bearing.
Thats's what we do in Victoria....... my 2 cents (1 cent US) worth.

John B
Victoria
AUSTRALIA

RE: OS140 Troubles
 

My local bearing supplies had a generic bearing as I said above.
He "thought" he could get the NTN but it may take a few days.
He can and now is, getting a stainless steel bearing by tomorrow lunchtime for me. Ill leave the seal in on the front side.

I have a "bonnet scoop" I put in myself to get extra air in on the bearing area of the motor, the cowl didnt come with one, and will enlarge the cooling / outlet holes I have in the belly pan to get them closer to four times the inlet area. Now its about 2 to 3 times the inlet area.

I guess I should also bump up my oil content to 17% for the cooling properties only. Im sure 15% is enough lube for these size engines. A two stroke brushcutter, of not much larger capacity doesnt use anywhere near 15% oil for lube, more like 5% at the most. Granted its not quite the same operating conditions or stresses but . . .

RE: OS140 Troubles
 

Here is some good info on setting the OS 140, by Dave Lockhart from the NSRCA discussion list that I had on file.

To add to several of the recent posts RE 2Cs, some misc thoughts/data from my experiences.

The question has been asked, how much power is enough/needed - how much more is needed? If you have enough power, and it is consistent, quiet, friendly, smooth, reliable, cheap, etc - you don't need more. However, having too much power (haven't found it yet myself) allows several things - milder cams, smaller carbs, lower compression, richer needle setting, lower nitro, milder porting, milder tuned exhaust systems, etc - all of which are essentially trading "extra" power for something else that is nice to have - ie, cheaper, quieter, consistency, more linear response, more torque, etc.

With 2Cs, I've posted before how the exhaust system can have a huge influence on not only the peak power of the engine, but also on the midrange running characteristics. Tuning the exhaust for peak power usually has some nasty side effects - non-linear throttle and rich/lean spots in the mid-range being the biggest nasties. The old "traditional approach" to mitigate the nasties was to test many combinations of props, plugs, compression, nitro, oil, pipe lengths, pipe designs, and port timing on the engine itself. The point in time when the "average" pattern flier probably knew the most about the "traditional approach" was probably in the mid to late 1980s - piped 2C 60s were propped between 13,000 to 16,000 RPM on the ground (10-11.5" diameters and 7-9" pitches), and the tune length of the pipe (diverging/converging cone type, mufflers were rarely used) was 13-15" (plug to baffle). After the introduction of turnaround and noise limits, and just prior to the 4Cs becoming dominant, 10,000-12,000 RPM (11-13" diameters, 9-12" pitches) and 17-20" (diverging/converging cone type, and baffle type, still no mufflers) were the norm for 2Cs. A couple 2C guys on the fringe were running even bigger props, with longer pipes, and lower RPM. My personal setup at that point (1992) was a Webra Race 61 LS w/ Dynamix using a CF pipe set at 22" and turning an APC 13-13N at about 9,500 - not a friendly setup - few aside from myself could set the needle, but the power was awesome, and whisper quiet.

Today, the "traditional" approach to tuning a 2C still works, AND, some new approaches exist - the OS EFI system and the MC carb system. The "traditional" approach today includes tuning the engine not only for peak power, but for peak power at a lower RPM and with linear throttle response as well - and relative to the mid/late 1980s, the average pattern flier knows substantially less about 2C tuning. All three systems will yield the same amount of peak power - EFI and MC do not yield more top end power. However, when the goal is peak power AND a smooth midrange - it is easier to achieve that goal using EFI or MC - the "traditional" approach requires substantial 2C knowledge and/or experimentation. Very often the "traditional" approach sacrifices a little bit of peak power to get the smooth midrange (and retain some flexibility/consistency) and it is for that reason that the average EFI or MC setup produces a tiny bit more power than the std carb (traditional setup). The "best" 2C setup, IMHO, is going to be one that is "traditionally" setup with the addition of EFI or MC, to allow very fine tuning and more consistency and flexibility (with regards to changing weather, props, fuel, etc). A very poorly setup 2C is not going to become wonderful with the addition of EFI or MC.

Aside - in my experience from running the OS140 EFIs and 140 RX - the EFI system has a "sweet" spot - it wants to be propped between about 7,700 and 8,300 RPM on the ground which will yield about 8,300 to 9,000 RPM in the air - if the 140 EFI is setup outside of that range, the power drops substantially. OTOH, an OS140RX can be tuned to run extremely well from 7,400 up to 8,800. I've not found a 2 plug head to provide more power or a lower idle - but the needle setting becomes less critical. And while Shadel piston/sleeve is a great weight saver (40 grams), I've not found it to produce any more power. And if the engine ever gets hot on the ground, the stock setup (ringed) idles a little better (never noticed a difference in the air tho).

Regards,

Dave Lockhart
[email protected]

RE: OS140 Troubles
 

Update.

I got a stainless steel bearing, and have installed it with no problems. (almost none, I half knocked out the front bearing when dropping the crankshaft and new bearing in, but whilst it was hot it was no problem to tap it back in place) Thanks for the tips on how to do the job. On getting the bearing I decided, (not sure if it was the right thing or not) to remove both seals from the bearing and flush out the grease that was in there. I guess time will tell if I did the right thing or not. Like most things in this hobby, everyone will have a different opinion on what is right and whats not, time will tell here.

Unfortunately the weather here has been cruddy for the last week so no chance to run the engine yet. Maybe over the weekend if I can get motivated to get up early enough. Its been so hot and humid that simple outdoor activity leads to sweat drenched clothes in no time so Im really in no rush.

RE: OS140 Troubles
 

!8-20% oil is advisable for a new OS 140. BTW Caster oil takes heat out better than synthetic oil.

RE: OS140 Troubles
 

OK, I increased the oil and nitro content to approx 18% and 15% respectively. I also stripped down the carby completely and found nothing to hinder its operation. After starting and ground running to reset mixture and see if the mid range problems still existed for approx 4 mins, I was satisified it was running much better. I shut down and let it cool off for about 20-30 mins. After refilling the tank I started it again and after another brief check, took off. Flew great for about 3 mins, all the time I was varying the throttle, then it just died. I dont recall exactly where the throttle was when it died but Im guessing about 3/4 open. In the resulting overshoot into long grass I managed to break the undercarriage mount plate, bend one gear leg and tear out the tailwheel, all fixable. Almost took out a large bird feeding in the grass too.

Why did it just die in flight ?
The OS-F plug still has a good glow BUT is looking a little frosty white. It wasnt a new plug that Id put in, it came out of my YS63 as I didnt have any new OS-F on hand when I got this motor. Ive never had so many problems getting new motors to run.

RE: OS140 Troubles
 

Do you have ALOT of cooling air? I had overheating problems with my OS 1.40, but took the dremel to the cowl and it fixed the problem. Try flying the plane with the cowl off and see how it behaves. . .

RE: OS140 Troubles
 

The frosted look on the plug is not good. The element is breaking down or glazed. A glazed plug will look hot with power to it but will not stay light well because the glaze insulates the platinum from the chemical reaction to the achohol. Mine do that after about 40-50 flights.
The only time I have problems with mine is when the bearing was going bad. Ran good at idle and top end but would load up and die in the midrange mostly after a downline or when throttling up to an upline. Check all of you fuel system lines. The clunk line may have a pin hole in the pickup line. Check the tubing between the pump and needle to the barrell for pinholes.
How old is this engine? Could be a weak ring if it has a lot of miles on it.

Wayne G.

RE: OS140 Troubles
 

Cooling is good AFAIK. I have the front openings (main one below spinner and a scoop at the top) at approx 25 square cm's in area and the belly pan openings (large one around stinger and two long ones either side of pipe forward of stinger opening) at approx 90 square cm's.

Ive changed the plug now but as yet not had a chance to fly it. The engine is new and has had only been airborne 3 times so far.

At the moment the header pipes effective length, measured in a straight line from the exhaust flange on the cylinder to the start of the pipe is 236mm. Standard OS/hatori header #915 and OS/Hatori 2C-140 #900 pipe.
Does anyone have this setup and if so what effective header pipe length do you have ?

RE: OS140 Troubles
 

Lanciar,

The basic break in for this engine is to run on the ground for about 2-3 tank fulls.
Start it up and run the top end till you have a nice rich 4 cycle.
Then turn the needle in til it starts to two cycle or run smooth for only a couple of seconds then turn it back out till
it is rich again. Do this for at least 2-3 tanks. This proccess lets the ring seat with out it getting to hot.
All the OS 1.40's I have broken in or helped break in
run very good when following this procedure.

I use 15% Cool Power that has 17% oil

Give that engine some running time with 3 tanks on the ground then put it in the air.
Set the high end needle till it peaks to a good two cycle.
Then bring it to and idle and let it set for at least 20 seconds.
When you open the throttle if it burbles rich and wont clear out till you go full throttle
then turn the low end screw clockwise less then 1/8 turn and try again.
If it suddenly quits when opening the throttle turn the low end needle to the left or counterclockwise.
Do this till the engine will respond smoothly on opening the throttle.
This engine seems to break in the best when it is in the air. But it needs to have the ring seat some before going in the air.
I am sure you will find it to be very predictable and an easy engine to use.

Wayne

RE: OS140 Troubles
 

This morning in relatively calm conditions I had a slight misjudgment of distance that resulted in CFIT. Controlled Flight Into Tree.
The crash flight was the first time Id completed a flight and was attemping to land with the engine still running for the first time. Apart from one little cough or hesitation I thought it was running great. On my third approach from the north I had it looking good speed wise but about 1/2 way down our strip for a touchdown point. As I powered up for the go around I noticed the streamer on my Tx antennae showing a downwind now.
I flew once around and made my approach from the other direction. We have a stand of trees along a creek bank at that end of the field, I thought I was inside them as I continued a descending turn onto final, the left wing caught a branch and ripped the wing off, the rest of the model with the right wing half off, did a graceful slow spiral landing nose first in soft dirt, 20cm from a wet and boggy, 1m wide drain. Damage to the fuse and right wing was a smashed wing tube socket in the fuse (obviously) damaged right wing tube socket, damage to the left side where the wing root trailing edge smashed in as it was forced back and some minor shatter cracks to the canopy. The left wing lodged in the tree, roughly 40 feet off the ground, surrounded in thick weeds, small trees, large trees, lantana (spiky nasty thick vine type plant) and hanging over a deep creek about 60 feet wide. After a club member went home and returned with a large fishing rod and lots of lead weights we attempted to hit/shake it down. Probably several hundred meters of lost line and dozens of lost sinkers later we gave up.
A guy who lives nearby came by on a motor bike and saw me looking up into the trees. He stopped, saw my predicament and offered to return with a chainsaw. 20 mins later we cut the tree down, due to its location and existing lean we had no option but to drop it in the creek, immediately after it fell I was in swimming, after diving for about two mintues I think my foot kicked the wing dislodged it as it floated up right beside me. Due to my limited building/repair skills the wing is finished, so unless I can get a new wing set for less than $275AUD, my time with the Arresti is over. Luckily I still have all the servo's, (the one that swims has been pulled apart, flushed with pure water and is now drying, hopefully it will still work) engine etc etc to put in something else. At this stage maybe an Adrenalin 90 with the arresti gear in it, OS140RX included. :-) Ive seen one done and a mate is putting a Moki 135 in one, could be fun and at $275AUD for the airframe, why not !

RE: OS140 Troubles
 

man that really sux!!!!!!!!!!!!!!!![:'(][:@] but at least you get a nice new shiny plane!!:D[8D]

hope you have more luck with the next one

RE: OS140 Troubles
 

Yeah but this was a shiny new one.

I keep having thoughts that maybe it is repairable in the hands of a craftsman. Trouble is I dont really know anyone. I might take pictures and post over in crashes and repairs to gauge peoples opinion on whether or not it makes the grade for reapairability.

Its going to be while off before I can get a new one, so no pattern comps unless fly my old Lark.

RE: OS140 Troubles
 

I watched this go in, and how it did bring back memories.:(

RE: OS140 Troubles
 

Im weighing up my replacement airframe options. So far getting another Arresti is looking the most promising. With a limited budget and lack of available 2M pattern models in Australia for a limited budget It makes economic sense. For a start Ill be getting spare parts in case of further mishaps (cowl, belly pan, canopy etc) and Ill get to fix the minor and major errors I made when putting the first one together.

If the Icepoint was available in Australia it would be a serious contender for a replacement I think.

RE: OS140 Troubles
 

I rang my LHS this afternoon to ask how his enquiries re replacement wing set for the Arresti had gone.
To my surprise he told me they were on the way. At $140AUD for a set he didnt wait to ask me if I wanted them or not. So now just to repair the fuselage sides and centre wing tube.

RE: OS140 Troubles
 

The wing deal didnt eventuate, someone doesnt know who told who or whatever ? No deal at that price anyway. Still evaluating options but its not looking good, no finance available right now for a start.

Can anyone tell me if its possible to run the OS140 on any other sort of pipe/muffler so it doesnt have to be installed in a model with a huge long pipe tunnel ? I dont really want to sell the engine and would like to use it in something else unitl I can afford a pattern plane again.

RE: OS140 Troubles
 

Hi Lancair

I just spotted this thread and read through the whole sorry saga. I feel your pain! [sm=crying.gif]

sigrun

RE: OS140 Troubles
 

I've run the OS1.40 on tuned pipes, bolly mufflers (look like tuned pipes) and I also used a canister type muffler when I didn't have the room ( I think it was from KM). The engine ran well on all of them.

RE: OS140 Troubles
 

Found this thread very helpful so figured I would add my experience today.

I had a dead stick today, then checked glow plugs, fuel, and needel for trash.

Started right up, went to wide open, taxied out tried to take off and no mid range/transition and just died. This engine was bought second hand and I have 17 flights on. The engine has run flawlessly so far. I read about the bearing problems and stripped it down. Found the problem I hope. Here's a pic.

RE: OS140 Troubles
 

Thats the rear bearing that is fairly rusty. I knew it felt bad but didnt have any replacement yet. I'll try to find one tommorrow and should have some more at houston contest.

Curious? Has anyone tried the ceramic from Boca?

RE: OS140 Troubles
 

Just reading through this thread made me sooo--- glad that I abandoned my (early) OS 140 when I did----the 160 is a heck of a lot easier!!!