Jump to content

NGH 4 stroke petrol mix


Graeme White
 Share

Recommended Posts

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 by Graeme White
Link to comment
Share on other sites

  • Graeme White changed the title to NGH 4 stroke petrol mix

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. 

  • Like 1
Link to comment
Share on other sites

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.

  • Like 1
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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 by Gary Manuel
  • Like 1
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

244376305_1097328934355483_833221330818060456_n.jpg.4d4605de730390c1b2da29db6f1e1389.jpg

 

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 by Jason Channing
Link to comment
Share on other sites

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. 

Link to comment
Share on other sites

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………….

  • Like 1
Link to comment
Share on other sites

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 by Cuban8
Link to comment
Share on other sites

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,,,

Bielle 3-2048.jpg

Link to comment
Share on other sites

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.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...