Glow motors and oil content - why so much?

[Paul De Tourtoulon]

1 hour ago, EarlyBird said:

Hm you have a few then, unfortunately I don't have any so I can't try a mix to suit me. What can I do, along with everyone else in the same position, but listen to an expert and follow their advice. 

 

Steve

Ask your local club what they would use on your engines, ask the no nonsense pilot who arrives gives his engine a flick to start and doesn't fiddle with the mixture needle each flight, I prefer more oil  less power isn't a problem you can just put a bigger engine in.

[Mike Mc]

I think that the type and quality of the oil is as important as the amount. The modern synthetic oils are much better than the oils of 40 years ago.

 

If you ask the local experts about fuel, also ask what type and brand of oil.

 

I really like KL-198, that's all I use.

 

[EarlyBird]

19 minutes ago, Paul De Tourtoulon said:

Ask your local club what they would use on your engines, ask the no nonsense pilot who arrives gives his engine a flick to start and doesn't fiddle with the mixture needle each flight, I prefer more oil  less power isn't a problem you can just put a bigger engine in.

Thanks, I will ask one of the LMA guys. On second thoughts I will ask @Jon - Laser Enginesas I am so impressed with his expertise, and it will be a Laser as many of my club mates are proud owners of Lasers. John has four in one model and the sound of four running at the same time is music to anyone's ears but what impressed me most was how easy they were to start. I wish I could remember his name begins with R the model is a refurbished model and engines, a Lancaster just flew over on it's way back from Elvington, sorry Jon the sound of those four Merlin engines beat your Lasers.

 

Rickett?

 

Steve

 

 

[Paul De Tourtoulon]

I have a Laser, and it does run on any rubbish even my 'c' mix,,,🙃

 

 A local has a B 29 with four of them and is building a Lancaster with another 4 lasers.

Edited August 14, 2022 by Paul De Tourtoulon

[Don Fry]

Paul, I love you. But caster oil was going out of fashion when the Model T Ford was hot technology. I can eat rubbish, but it might not do me any good. 
Fancy one to get up the Autoroute?
T Ford, not my backside.

[Paul De Tourtoulon]

Out of fashion, I still live in the 60's and miss the Geordie accent , real food, and Marmite, not forgetting Monty python, those were the days 😉anyway it will all eventually come back into fashion.

[Jon H]

So much to unpack. 

 

In order:

 

EB, i think saito recommend 20% full synthetic in their instruction, but the UK distributor puts a card in recommending 20% castor. This was the case some years ago when i worked in a shop. When i asked the distributor why i was told they thought it was better as pure synthetic was bad. Apparently they know more than saito? Now i recommend 15% synthetic, and i know i will now be called a hypocrite for thinking i know better than saito, and on the one hand that is true, but at the same time i am not exactly out of touch with engine design and know that saito have a margin of safety built into their recommendation. 15% good quality synthetic is safe to use but i would be wary about going lower due to their conrod design. 

 

Masher, yes..yes a thousand times. 

 

Paul how long does it take to tune an engine? 5 seconds? such a waste of flying time. Truly shocking, i am not sure how i survive. And Lasers will run on anything, but just because it 'works' it dosent mean its right. And you should use the right fuel for the right engine, not invent things. I do however agree that self professed experts are best ignored. But if you find someone with genuine expertise then you should probably listen to them. 

 

Mike, if you lost a little power you might be able to get it back with a prop change. Cant remember what you are running but props make the most significant difference, way more than nitro. On the oil side, you might be ok with 12% even as low as 5% nitro but i am not confident enough to recommend it and have your rod give up the ghost. If you wanted you could work out the mass flow of oil through the engine on a known good fuel by measuring fuel consumption, working out the % oil in cc/min and then calculating it all back to a lower...nah stuff it its too much like hard work. Also be aware of confirmation bias's in your loss of power determination. If you didnt know what fuel was in it, would you notice it was down on power? You expected less power and saw less power, but was it the fuel or the fact that its roasting hot at the moment and the air pretty thin. This too makes a big difference to engine output. 

 

Paul again, if you have enough oil you do not need more. Adding more and costing yourself performance is pointless. Also fitting a bigger engine is a poor solution. The larger engine is more expensive to buy, uses more fuel, makes more mess etc. Also the performance changes being discussed when it comes to oil content are relatively small. Even the 500rpm sort of numbers i have seen on our flat twins are smaller than the step between engine sizes. Its nice to have, but not life changing. 

 

Mike again. yes, quality over quantity every time. This is part of the reason i started investigating low oil here at Laser. Things have moved on. 

 

EB, yea we aint beating that! 

 

 

 

 

[Eric Robson]

2 hours ago, Paul De Tourtoulon said:

Out of fashion, I still live in the 60's and miss the Geordie accent , real food, and Marmite, not forgetting Monty python, those were the days 😉anyway it will all eventually come back into fashion.

Howay back yem then, It's been as hot as France ower here, 

[PatMc]

55 minutes ago, Eric Robson said:

Howay back yem then, It's been as hot as France ower here, 

Nor at Seaton Sluice it hisn't, the seafret's kept the temp doon!

[Paul De Tourtoulon]

Quote,

 

. But if you find someone with genuine expertise then you should probably listen to them. 

 No they listen to me.🥳, and i don't take myself to be JC.

 

Quote,

The larger engine is more expensive to buy, uses more fuel, makes more mess etc.

 

 Who cares, out on my Aprilia, 200hp and it nearly drinks as much as the V 8 in my Jag.

If you don't want to spend money on RC toys go fishing.

 

[john stones 1 - Moderator]

You've said your piece fellas, give it a rest please.

[Jon H]

1 hour ago, Paul De Tourtoulon said:

 

 No they listen to me.🥳

 

 

 

 

F 

[Eric Robson]

6 hours ago, PatMc said:

Nor at Seaton Sluice it hisn't, the seafret's kept the temp doon!

The fog on the Tyne is spreading to LindIsfarne via Seaton Sluice 😄

[Martin Harris - Moderator]

Is the writing on the wall for synthetic oil?

 

 

Not serious BTW - just getting a bit stir crazy on the family holiday in deepest Cornwall…seen at the Eden Project today. 

[Don Fry]

I feel for you Martin.

[Aussie Glow]

Hi Guys, getting back on to the topic regarding oil in 4 stroke glow engines, call me mad but I for many years have only run 8% good quality synthetic oil, 10% nitro and 82% methanol and just a shade rich mixture on peak RPMs with a full tank so as it’s probably peak lean on a vertical pull up and when the tank is nearing empty. 
Im running 3 Saitos FA 91 and 1 very old OS rear cam 90. The only maintenance I’ve done on these high hour engines are the crank bearings and tappet settings. Tappet settings on the Saitos, I set 0 to max 1 thou clearance.

One modification I’ve done on the Saito engine is to put the breather nipple on the side of the cam box so all oil vapours go past the big end, through the main bearing with seals removed and exit out lubing the cam lobes and lifters. The old OS 90 breather is next to the cam box/ shaft.

Providing you are running a good quality sealed front bearing and the breather is exiting out into the airstream, the model stays remarkably clean and no need to wipe down after a solid day of flying.

One of the Saitos has consumed at least 160 -180  litres of fuel, all original apart from usual bearing replacement, I’ve never had the piston out of its barrel so don’t know how much carbon build up but exhaust valve is visibly clean, still has great compression, don’t know if you can actually wear out one of these engines if they are well looked after. 

The main reason I run a low oil content is it gives very reliable slow idle and super easy starts and no slobbery oil dripping off the model, I have gone down to 5% nitro but I like to keep my engines running just a bit harder to give the 2 strokers a run for their money.

I definitely wouldn’t run this low oil content through a 2 stroke, reasons previous mentioned.

I’d certainly recommend 10% oil mix with in a Saito with the breather moved next to the cam box, they just run so much better and cleaner.

Previous experience with Saitos is the cam does run dry when the breather is at the rear of the case.

Thats my 2 bobs worth.

Adios 😃

 

[Mike Mc]

2 hours ago, Aussie Glow said:

Hi Guys, getting back on to the topic regarding oil in 4 stroke glow engines, call me mad but I for many years have only run 8% good quality synthetic oil, 10% nitro and 82% methanol and just a shade rich mixture on peak RPMs with a full tank so as it’s probably peak lean on a vertical pull up and when the tank is nearing empty. 
Im running 3 Saitos FA 91 and 1 very old OS rear cam 90. The only maintenance I’ve done on these high hour engines are the crank bearings and tappet settings. Tappet settings on the Saitos, I set 0 to max 1 thou clearance.

One modification I’ve done on the Saito engine is to put the breather nipple on the side of the cam box so all oil vapours go past the big end, through the main bearing with seals removed and exit out lubing the cam lobes and lifters. The old OS 90 breather is next to the cam box/ shaft.

Providing you are running a good quality sealed front bearing and the breather is exiting out into the airstream, the model stays remarkably clean and no need to wipe down after a solid day of flying.

One of the Saitos has consumed at least 160 -180  litres of fuel, all original apart from usual bearing replacement, I’ve never had the piston out of its barrel so don’t know how much carbon build up but exhaust valve is visibly clean, still has great compression, don’t know if you can actually wear out one of these engines if they are well looked after. 

The main reason I run a low oil content is it gives very reliable slow idle and super easy starts and no slobbery oil dripping off the model, I have gone down to 5% nitro but I like to keep my engines running just a bit harder to give the 2 strokers a run for their money.

I definitely wouldn’t run this low oil content through a 2 stroke, reasons previous mentioned.

I’d certainly recommend 10% oil mix with in a Saito with the breather moved next to the cam box, they just run so much better and cleaner.

Previous experience with Saitos is the cam does run dry when the breather is at the rear of the case.

Thats my 2 bobs worth.

Adios 😃

 

Do you have a photo of the new breather location. I would like to give that a try.

 

[Paul De Tourtoulon]

I used to run 12% aero synthèse oil sold by Graupner ( Carbulin ? ) in my 4 strokes and no caster oil, but with the mix of different 2/4 strokes and helicopters 12% is as you say to dry for 2 strokes.

[Aussie Glow]

Photo 1, a bit hard to see under the cowl but that’s it.

Photo 2, the black dot is where I’d drill and tap thread, making sure that you don’t drill too close to the lifter bore, very self explanatory when you have the cam box apart. I use the existing nipple, block the hole in the rear case, make sure the nipple doesn’t screw too far in as it could hit the cam lobe so when tapping thread, make it a tight thread, with the breather tube exit it with some brass tube into the airflow under the cowl or attach to an UC leg, no more oil on model.

Works very well for me on 3 Saito FA 91s

Good luck. 😃

[Jon H]

I am in complete agreement with you Aussie glow but my only caveat is that i think the saito FA91 has a bronze bushed conrod and not the plain one modern saito engines do. This would be far better with low oil. 

 

I tried to find a photo to see if it is bushed but couldnt find one. 

[Aussie Glow]

Gidday Jon, attached is a picture of a Saito FA91 big end  ( the Saito in pic #2 ) it doesn’t appear to have a bushed big end.

I don’t know this engine history or age as it was given to me in bits and pieces some years ago and not sure if all Saitos use an un-bushed big end.

 

I’ve never had the pleasure of owning a Laser engine, always used Saito 4 strokes and one sweet old OS rear cam 90 engine in a trainer used for ab initio students on club days that just keeps on going. 
When a Saito finally wears out, I’ll look for a Laser.  😃

 

[Aussie Glow]