Graeme White Posted October 2, 2021 Share Posted October 2, 2021 (edited) Evening all I have tried searching for this answer as it has probably been asked before but I couldn't see anything. I have recently acquired a model with an NGH 38cc 4 stroke installed. I'm going to try and get it running on the next nice day we have but I am wondering about fuel. I was told off by the wife previously for bringing petrol in the house so I am thinking of going for aspen fuel which I have heard about and like the sound of it not going bad as I don't fly hours a week so can't imagine the extra cost is going to be significant. Is it true that it is much lower odour? Will the engine require retuning much? Also, what 4 stroke oil do people recommend? I really don't want to be faffing with maintainence so want to make sure I have the right stuff or if halfords lawn mower 4 stroke oil stuff is fine? Edited October 2, 2021 by Graeme White Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted October 2, 2021 Share Posted October 2, 2021 You want a 2 stroke oil Graeme, mixed in your fuel, plenty choice on which oil, have a browse and choose one. I use a Castrol one. Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 2, 2021 Share Posted October 2, 2021 You need 2 stroke oil to mix with the fuel. The SAE30 type lawnmower oil is for wet sump 4 strokes and not blow by lubricated 4 strokes as used in models. The best people to call would be justengines as they sell NGH and will have all the info you need. I have heard good things about the deluxe materials 2 stroke oil though so this might be worth investigating. Aspen fuel is very good and has only a slight smell. Its more like a white spirit smell than petrol. You can get 2 versions. One is 4 stroke in a blue bottle and has no oil so you have to add as much as you want. The other is the 2 stroke in a red/orange bottle and it is mixed with a very good oil at 50:1. In theory, the NGH should be fine at that oil level but to play it safe follow the just engines information. All engines need tuning when changing fuel, prop, model and the day itself can impact it too. Normally its only a small adjustment but its still worth taking the time to tune it for peak performance. Its only 5 seconds work after all. 1 Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted October 2, 2021 Share Posted October 2, 2021 Graeme, Aspen fuel should be the same settings as regular pump petrol, it's basically a synthetic version with the smelly aromatics left out. For the oil, you want a two stroke oil not a four stroke oil, four stroke oils are for engines with oil in the sump, the NGH38cc relies on e oil in the fuel. I use the Deluxe materials oil in mine, but any good two stoke oil should be fine, full instructions can be downloaded from Just Engines. John & Jon beat me to posting, but thought I'd add my two penneth worth. 1 Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted October 3, 2021 Share Posted October 3, 2021 Ngh advise on 3% + oil, I use 5% in my Saito FG-30 which still threw a big end, so maybe the Aspen 4 stroke mix with at least 4% of a decent synthetic 2 stroke oil. Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 3, 2021 Share Posted October 3, 2021 saito seem to suffer more than their fair share of big end failures irrespective of oil so i would not use them as a benchmark. The construction of the two engines is also very different. Quote Link to comment Share on other sites More sharing options...
Andy J Posted October 3, 2021 Share Posted October 3, 2021 Interesting that this topic has arisen as I have 5lts of Aspen 2 which I bought back in 2017 when I was also playing with an NGH38. Never used the fuel so will it still be ok and should additional oil be added to the fuel? NGH38 now sits in its airframe in a corner of the garage as I could not get the engine to stop throwing its prop. Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 3, 2021 Share Posted October 3, 2021 3 hours ago, Andy Joyce said: Interesting that this topic has arisen as I have 5lts of Aspen 2 which I bought back in 2017 when I was also playing with an NGH38. Never used the fuel so will it still be ok and should additional oil be added to the fuel? NGH38 now sits in its airframe in a corner of the garage as I could not get the engine to stop throwing its prop. The bloke i spoke to at aspen claims their 50:1 is fine in anything no matter what oil ratio is recommended. In fairness to him, i have had no issues at all with my time with the fuel and i am in effect running a glow engine on 1% oil. Whatever the oil is it is very good and the engine internals are immaculate after many years of running in my prototype engines. Admittedly this is a very small sample size, but i cant see a reason from my own testing why it would not work. That said, i cant promise anything as i didnt test it. Adding oil might be a mistake however as the new oil might not play well with the oil already in it. I would say use the premix orange bottle stuff as is, or get the blue bottle no oil stuff and mix to your own ratio. Dont add oil to the premix Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted October 3, 2021 Share Posted October 3, 2021 (edited) Graeme. I have an NGH38 which runs great but you do need to make sure that the valve gear gets well lubricated. Assuming that the engine is already run in, you'll need a good quality fully synthetic 2 stroke racing oil. I use Mobil 2T racing but other brands are available. The recommended mix is 25:1, which is a lot of oil presumably due to the valve gear requirements. I have a few different makes of engine and I tend to run them all on the same fuel mix. Before I got the NGH38, I used to run them all at 40:1, but now I have settled on a compromise of 35:1. It works for me but I am always wary of under-lubricating the valve gear. If you only have the one petrol engine or don't mind having the special mix, I'd push it to 30:1 or 25:1. Before you start it, take the valve covers off and have a look at the valve cams and give them a good oiling (and adjustment) while you are in there. P.S. It's a great engine with a very distinctive sound and it will amaze you how little petrol it drinks. Edit - Correction. I've just looked at the manual and 25:1 is only for running in. 35:1 is the correct mixture for this engine once run-in. Edited October 3, 2021 by Gary Manuel 1 Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted October 3, 2021 Share Posted October 3, 2021 4 hours ago, Andy Joyce said: I NGH38 now sits in its airframe in a corner of the garage as I could not get the engine to stop throwing its prop. Check the ignition timing, some of the earlier ones the timing was too advanced and they vibrated a lot. Mine is quite smooth, for a 38cc four stroke, and has never thrown a prop. Not overly powerful, but quite easy to operate. Quote Link to comment Share on other sites More sharing options...
Andy J Posted October 3, 2021 Share Posted October 3, 2021 Did check the timing back in 2017 but could never cure the vibration and prop throwing. Did change the plug for an NGK type and purchased the Aspen fuel but never got round to running the engine again as other projects got in the way. Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted October 3, 2021 Share Posted October 3, 2021 There's some posts here on various ignition settings https://www.rcuniverse.com/forum/gas-engines-142/11298314-ngh-38cc-4-stroke-50.html Probably going a bit off topic, but it looks as though the standard Rexel ignition unit advance curve isn't optimised for the NGH 38cc, for max power it needs around 40 deg BTDC, but to keep vibrations and kick back 30 Deg BTDC works better but loses some top end power. Quote Link to comment Share on other sites More sharing options...
Jason Channing Posted October 3, 2021 Share Posted October 3, 2021 (edited) Keep a note of Just Engines email and phone number as you'll need the spares? Here's one I bought at a HobbyKing open day for £1 as scrap, best value paper weight I've ever bought and as an instructional tool, However quality is certainly not evident. Edited October 3, 2021 by Jason Channing Quote Link to comment Share on other sites More sharing options...
Graeme White Posted October 3, 2021 Author Share Posted October 3, 2021 Thanks for the help all. The bloke I got it off said it was half run in so will stick with 35:1 and check the valves every now and then. I'll grab some 2 stroke oil soon and give it a go! Mixed opinions on the engine so hopfully mine is one of the better ones! 1 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted October 4, 2021 Share Posted October 4, 2021 On the original NGH instruction sheet they specify 25:1 for running in and 30:1 for general running. 1 Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted October 4, 2021 Share Posted October 4, 2021 43 minutes ago, Engine Doctor said: On the original NGH instruction sheet they specify 25:1 for running in and 30:1 for general running. Ah that explains why I thought I was compromising at 35:1. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted October 4, 2021 Share Posted October 4, 2021 Mine are NGH 2 stroke, started on 25-1, now 30-1, running fine and not a lot of gunk to clean off. Quote Link to comment Share on other sites More sharing options...
Don Fry Posted October 4, 2021 Share Posted October 4, 2021 I’ve got a Ngh 25 2 stroke. It currently resting between jobs. It runs on the 50 to 1 mix every other 2 stroke runs on. No sign of stress, heat etc. Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted October 5, 2021 Share Posted October 5, 2021 12 hours ago, Don Fry said: I’ve got a Ngh 25 2 stroke. It currently resting between jobs. It runs on the 50 to 1 mix every other 2 stroke runs on. No sign of stress, heat etc. Ok but how much running have you done ?, i got through around (all petrol engines ) 120 litres last year, and 'only' about 30 this year,, Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 5, 2021 Share Posted October 5, 2021 27 minutes ago, Paul De Tourtoulon said: Ok but how much running have you done ?, i got through around (all petrol engines ) 120 litres last year, and 'only' about 30 this year,, An engine without enough lubrication will pack up almost instantly so length of run is not super important. The limiting factor for lube in all model engines is the con rod big end. It has lots of work to do and will be the first component to protest. If it didnt seize up immediately, then its doing fine. Quote Link to comment Share on other sites More sharing options...
Don Fry Posted October 5, 2021 Share Posted October 5, 2021 37 minutes ago, Paul De Tourtoulon said: Ok but how much running have you done ?, i got through around (all petrol engines ) 120 litres last year, and 'only' about 30 this year,, It’s done about 200 hours on that mix. Oil used is a Motocross bike oil, so a very high quality thing. My club is next to a serious Motocross track, and if you ask nicely they will sell a liter. I’ve not inspected it’s innards. Not broke…………. 1 Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 5, 2021 Share Posted October 5, 2021 54 minutes ago, Don Fry said: Oil used is a Motocross bike oil, so a very high quality thing. Quality over quantity every time ? Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted October 5, 2021 Share Posted October 5, 2021 (edited) I don't own a NGH petrol four stroke, but rather like another range of budget engines from Russia, my experience of seeing club mates' with them is not very encouraging. Out of half a dozen engines that I know of, not one has been satisfactory in one way or another. Faults range from general poor running and regular engine outs to mechanical failure that required two returns to the distributor and eventually a refund. Caveat Emptor. Edited October 5, 2021 by Cuban8 Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted October 5, 2021 Share Posted October 5, 2021 I do not have a model type 4stroke engine, or even seen one really close up. So, exactly how are the internals like valve gear and crank related stuff lubricated ? Wet sump ? Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted October 5, 2021 Share Posted October 5, 2021 2 hours ago, Jon - Laser Engines said: An engine without enough lubrication will pack up almost instantly so length of run is not super important. The limiting factor for lube in all model engines is the con rod big end. It has lots of work to do and will be the first component to protest. If it didnt seize up immediately, then its doing fine. My Saito FG-30 big end on 5% motul 710 ( 20€ the litre ),,, next to my bronze home made one,,, Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.