When is too little, too little (oil)?

[Old Red]

I don't post much, but am always amazed at the trial R/C'rs put themselves through with oil.

I don't claim to be am expert, but I have been flying gasoline powered planks since '80 and helis since 88 (my own conversion).

Up until last year I always ran your standard 40:1 pennzoil, and now I am running the Ryobi 40:1 synthetic (good stuff).

Am I lucky? I don't have plug problems, rough running problems, and I've yet to wear out a motor. I have an X-Cell gas I built in, gosh maybe 98 or so that has now over 40 gallons through it and it still purrs.

What say you? I say stop goofing around, go down and buy what all the chainsaw boys are using; it has worked for them for a long time in a much higher demanding environment.

[FCM]

Hi John,

Plug is a NGK CMR7H set at 0.020".

Removed the exhaust and the piston crown, although black, has minimal deposits on it although it is wet with oil as is the exhaust port and the exposed skirt of the piston.

Ring is okay and no blow - by on the piston skirt. No signs of overheating evident.

Engine has run 3.98 hours since de-coke using the Motul 800 at varying ratios from 50:1 to the present 75:1. Ring is well broken in with around 20 hours on it from new.

I know the plug images I posted are pretty useless but it looks to me like I am still running too much oil especially when I take the appearance of the piston/exhaust port into consideration.

I am in the process of re-installing the GV1 and intend to lean off the oil and try again on Friday as I feel I still have some way to go before I run into oil starvation problems.

The oil I am using is apparently used at 100:1 ratios in "Trail Bikes" so I take some comfort from knowing that.

Thanks again for your help and opinions John - much appreciated :D

Paul.

[FCM]

Dear Old Red,

"What say you? I say stop goofing around, go down and buy what all the chainsaw boys are using; it has worked for them for a long time in a much higher demanding environment."

If only it was that simple! I cannot obtain any of the oils that are popular in the USA such as Amsoil, Klotz, Bel-Ray, Pennzoil etc.

Also we are operating a cameraship and the smoothness/consistancy of the engine is of paramount importance to us. Believe me it is a whole new ball game when you have a video camera strapped to one of these things showing up every little uneveness that occurs.

The only quality synthetic oil I have managed to find that has adequate support here is Motul but although the importers are a helpful bunch, surprisingly, they don't have any experience of running their product in a gasser cameraship so they can only give me info. that they are sure about based on their experience. Quite rightly so too.

If there is a better/easier way then I am all ears. Our running problems are in danger of producing a serious set back for our company if they are not sorted out soon. All I have to help me are the good guys on this forum and RR. I have indeed learnt so much from them but there is only so much that anyone can do to help me on an internet forum.

Anyway, fingers crossed that my next bout of testing does produce the consistancy that we require.

Regards and thanks for taking an interest,

Paul.

[bigrcr]

Just watch the deposits on the piston and exhaust side of the cylinder. These deposits can stick the ring. The carbon particles can also start a scoring on that side as they burn/break off. My piston/cylinder looks as if it just came out of the box-still shiny and new with NO deposits after many gallons of fuel. This is using Amsoil and camper fuel at 50:1 now. The plug and gap you have are correct. Pulling the extra weight of the camera equipment does make a difference though and your oil and needles may have to be tweaked to compensate. This additional load can itself make the motor hotter and burn impurities or additives and cause carbon build up.
It sounds like you have a very good grasp for what's going on. Being observant as you are should net good results as most motors that are burned up are done so by pilots that aren't as pro-active and don't know something is going on.

Another possibility on your "playing rough" is to really listen to the motor and sense if the roughness is "matching" what the motor is doing. If the motor sounds like it is running smooth and the machines actions may not match this, then you may need to look elsewhere. Bill Meader taught me a bunch of things,one of them was to do just this. Listen to what the motor is doing and see if the machine is responding to the motor or something else. If the motor is smooth and the tail is vibrating or kicking a bit and it doesn't match, the auto hub may be your problem.

Using Tri-Flow on the auto hub may not be the best thing to use. If you are using the split/gear sprag bearing set-up, this bearing is best lubricated with auto-transmission fluid or Marvel Mystery oil. The Teflon particles can effect the proper operation of the auto-hub, especially in the gas model. This bearing must also be lubricated fairly often, much more so than you would like to, in order to keep things smooth. Just re-lubing this bearing with fresh oil can/will take care of the tail kicking/unhappy problem. Try it if you are using Tri-Flow or have not lubed the auto unit recently.

Later,

[FCM]

John,

I don't think I can lube the auto bearing assembly on the Benzine as it is a sealed unit.

My roughness is I think, engine related as you can tell from the engine note when it is going to shake sometimes before you can actually see the shaking. When it is smooth it sounds smooth.

Time and time again I have looked for other sources of vibration but it always ends up being the engine.

My vibration, if allowed to continue unchecked, ends up shaking the left skid. When this happens you would swear that it is some head/blade imbalance that is responsible due to the relatively low frequency of the shake but again, it is the engine doing it not the airframe.

I have noticed that the engine loading is critical - just how you and BillM have described it. When it is shaking, sometimes a quick minimal adjustment up or down of the throttle curve hover point can elliminate the vibs completely. This is the reason I have reinstalled the GV1 as it should load the engine more consistanly than I can using the 5 point throttle curve on my X3180. It was a mistake removing the GV1 during my interference trouble-shooting.

Will be flying tomorrow to see if things are more consistant. Will let you know how it goes.

Paul.

[Waller]

Hey Paul,

Let me know if you want me to ship you some other brand of oil you can't get; I am sure we can make it happen.

Later!

[bigrcr]

Although this may not be the case in your situation, A left skid vibration has nearly always meant a lean condition on the mixtures (especially the low).

Later,

[FCM]

Warren,

Thanks for the offer - I will let you know if I can't sort things out with the Motul oil.

Just got back from testing with the M 800 at 85:1 ratio.

Started with the low adjustment at 1 3/8th and it seemed to respond very well. I flew with the GV1 selected on giving and engine speed of 11,000RPM.

I did lean it slightly and am getting a good transition and for the first time ever, the tail was responding with some side to side movement.

Tried leaning it some more and the skids started shaking so this must be the too lean warning as you mentioned John.

Plug is still black and wet with oil and removing the exhaust and looking inside seems about the same as at 75:1 ratio.

I feel as though I am onto something now as the running characteristics now seem to be like those described with the Amsoil at 64:1.

Could not take any meaningful video today but what I did shoot showed a marked difference when the engine was too lean (shaking) so this looks like it is going to work for me.

I feel that I am still running too much oil at 85:1 and once again, due to the oily plug I hope that leaning the oil off will give me a smoother running engine without any coke build up.

Will keep you posted.

Paul.

[FCM]

Flew for 1 1/2 hours this morning with the Motul 800 at 100:1 ratio.

Although it started off quite well, I found that I had to keep leaning it to stop the shaking. I also changed the engine speed on the GV1 first raising it to 11271 RPM and also tried lower at 10726 RPM. It seemed happier at the lower speed and I thought I had cracked it when I managed to richen up the low needle back to 1 3/8ths with minimal vibration. Plug is still wet with oil.

I shot some video and it looked okay but when I stopped to refuel, on restarting, as soon as the heli was airborne it shook really badly so I still do not have a consistant engine and wonder now whether I ever will :cry:

The options I have are to change to a lower grade Motul oil that is currently out of stock here, changing the carby or even changing the heli's gearing.

Where do I go from here :?:

Paul.

[Billme]

Paul,
What is your throttle atv's high, and low?
Are you still running the original plug?
What RPM are you trying to run with what blades?
Bill

[FCM]

Hi Bill,

My throttle ATV's are both set at 150%. This is how Tom Fiddler recomended when using the GV1/SG. The GV1 does seem to work well and it is obvious when it engages.

Today I was running a cleaned up NGK plug that has now run for 6 hours since it was installed with this engine following a de-coke.

I am running SAB 810mm mild S blades together with 9.09:1 gearing. The head speed today was between 1180 and 1240 rpm. Normally I run at 1210 rpm but I tried differing this a bit to see it the changing load did anything. The answer to that was no, it doesn't seem to make much difference.

I am now thinking that the oil I am using is just too heavy for the engine. I cannot seem to get it to burn properly and it is now leaving coke on the piston crown which shouldn't be happening with a fully synthetic oil.

The engine has run clean before using the semi - synthetic Motul 510 but in the end it does coke up and I seem to have to run a lot of it which makes the engine run hot due to the lean setting it requires.

Tomorrow I will be changing the oil to Motul 600 fully synthetic. One of the guys on RR is using this in his gasser at 32:1 ratio. Sounds like a lot of oil to me but I am willing to try just about anything to get a consistant engine run.

Thanks for responding Bill.

Regards,

Paul.

[FCM]

Latest news!

Today I ran the with Motul 600 at 50:1 ratio. I only flew for 3 tank fulls but I did end up with a very smooth engine once I had leaned the low and the high needles.

It's early days yet but I think I am stuck with running the low lean in order to get a smooth video image. At least I am doing this with fully synthetic oil instead of the semi that I used before. The weather was hot and sunny this afternoon which really put it (and me!) to the test. No signs of overheating/sagging so fingers crossed.

Earlier I met with the importers of Motul oil here and they advised the 50:1 ratio at least to start with.

They also told me that the M800 Road Racing oil that I had been running has a lot of additives to enable it to cope with the high loads of the 250 and 500cc GP bikes. It is NOT specifically a 'clean' burning oil and they were not surprised when I told them of the deposits I was getting on the plug. They also stated that changing the oil to 600 should not stick the ring as all of their different synthetics are compatible - I guess we shall see if this is the case very soon :wink:

From the way the engine is set up now it sounds as though I have strayed into the Larry Bergen method of Gasser engine tuning - not that I have ever seen it written down in the same way as I have seen the BillM method. From memory, I think Larry runs around 40:1 oil ratio? I don't know if I can run the 600 this rich as the plug is a bit wet around the outer body although it is much, much cleaner on the centre electrode and it also looks like I have some colour forming which is a relief!

Anyway, thanks everybody for your input so far :hug: - I hope that I can now get on and shoot some video without worrying about the image quality all the time.

Paul.