the pope

Thanks there husky ,
seeing that they make one for the head , something for the backplate would be good . I may make something up or maybe not !!!!!!! Im a bit anal when it comes to my engines so if it gets a bit beat up I wont be happy . My planes not so much , I don't hesitate to chop the crapper out of a cowl or run a plane without one for that matter . I mean to say why cover up a cool bit of engineering . Cheers the pope

hllywdb

I've been using straight premium with 10% ethanol for a year with no problems.

I'm with hsukaria on the backplate. A flat bar which fits snug get's mine off with no damage, same for the 40 nitro and 25's.

Be carefull pulling the head. There is a thin, delicate gasket that you don't want to ruin or you will have to wait for another. It's not the copper one used in the 40 nitro. If you don't have to pull the head, then DON'T.

fiery

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Pope

I would try Castrol R 30, Shell Racing M or Fuchs Castorene 40. Or Castrol A747, as suggested above.

If your local motorcycle dealer has never heard of these lubricants, he is a not a real dealer, just as sales depot. In that case just go to a real motorcycle service shop. They will help you out.

I have used the above oils in glow two stroke engines. I do not trust full synthetic oils for the lube package in the hot Queensland climate.

The above all work fine. No fouling of the plug at all. Your engine will love you for it. I have never worn one out.

hllywdb

As long as it is 100% technical castor, no sythetic or blends.

fiery

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Roger that. I run diesels mostly and have 20 litres of lubricant grade degummed castor oil on hand. I'm good for oil a while .

Very interested to see this engine, after messing with a Chinese spark ignition 9 cc supplied with a woeful carb and dodgy pump. Pope, what was total cost of the GX 40 including shipping to Australia?

A little off topic, but I reckon a GX 40 would make a great diesel conversion. Hllywdbd, maybe a word in the ear of the people at NV?

the pope

Hi there fiery $185 which included $22 for postage and also the head removal tool .Paypal added a bit to that as well . I got the $10 discount they had as well , not sure if this is still available . Im a big fan of castor as well , I just want to make sure I do this by the book as Id cry if I damaged the engine . Hllwdb I will leave the engine as is Im just looking to the future in regards to bearing changes etc .

hllywdb

fiery
They have probably looked at diesel, but there are lots of diesels out there. Gasoline 40's? Zip, just the one. I would like to see a gas 61 and 25 as well. They might as well go with it while they own the market.

hsukaria

I said this before, but I will say it again: I need a 60 gas. I am saturated with 40 nitros and I am going to have to sell a couple to justify this GX-40. But I need a 60, bad. I will wait till the gas NV 60 is available someday.

earlwb

huskaria, the Evolution 10cc gas engine is pretty good, everyone is pretty much thrilled with it.  Now then the NGH 9cc isn't bad but quite a few people are having problems with the pump/regulator and the carburetor as it works differently than they expect. So you have to fix them sometimes.

earlwb

Anyway, my NV engines 40 GX is alive and well and is running OK too. I am still running it in though. But I managed to kill the glow plug so I need to get a few in before I can continue to run the engine.

I have a concern about the muffler and how it mates up to the engine, as the mounting tabs are angled and the screw heads only touch on the bottom. The screw heads can bend and maybe break off. But it is a concern as apparently no one has complained about it being a problem so far that I know of. also the muffler face is ever so slightly curved, so it doesn't sit flat on the engine exhaust face. So you'll need to use a gasket. Now one thing I found with other brand engines was that the gasket has sides that are too narrow or thin and the sides tend to blow out in use when flying the engines, so I made a gasket with the sides more thick and that seems to help keep them from blowing out. Plus using a different gasket material may be a factor as the paper gaskets may not hold up all that well and burn out. Now then the muffler didn't come loose on me while running the engine so maybe it is a moot point. but I don't know for sure yet.

Then the carburetor, my example was a little too rough and gritty feeling. I think the helical groove cut into the barrel results in the rough feeling and some excess friction or drag. The friction can cause the pushrod to bend or flex a lot so the pushrod will need to be more stiff or supported better.

The removeable or replaceable threaded prop shaft is a great feature as it is the thing that winds up getting bent in crashes usually. But it is a little too short, if you want to use a spinner on the engine. But then if you don't want to use a spinner it is not a problem. But it was brought to my attention that you can unscrew the stub shaft and reverse it as the threads are longer on the other end. So to use a spinner you simply reverse the threaded stib shaft.

I was able to get the engine to run without using a electric starter on it too. It fired up fairly easily and that sort of surprised me. But it started running and running fairly good too. Maybe my running it too rich for a while contributed to the glow plug failing but that is water under the bridge now. I'll get some more in soon.

I used a Master Airscrew 11x6 propeller and I was getting a little over 11,000 RPMs with the engine and it is still not broken in yet. So it ought to do better than that as it gets run in more. I used pump gasoline along with Klotz Benol oil. But 11,000 RPMs has the engine running up there about as good as some .45 glow engines I have run in the past.

Oh yeah I almost forgot to mention that the Tygon fuel tubing will start to melt on the muffler fitting. So you can use a a short length of silicon fuel tubing there if you like. Since the exhaust is burned fuel, the gasoline won't affect it very much if any.

earlwb

Oh yeah and here is a short borring video of me messing around with the NV 40GX engine too. I had to make a adapter for the engine test stand as the muffler ran up against the right side mounting clamp nut and bolt.

[youtube]http://www.youtube.com/watch?v=cE3l1zdJcPw[/youtube]

blw

My Feedback: (3)

Thanks for the pic of the shoddy screw fit. The short crankshaft is going to be a problem too.

downunder

The removeable prop shaft is designed to be turned around in the crankshaft (different length threads) for use with either thick or thin prop hubs. I don't know why your muffler has that tapered face because the 40AX (glow) muffler has a parallel face.

the pope

Hi there D.U. mine arrived today and its the same as Earls . A bit strange for sure , also I thought the gas versions had a muffler that came straight out and not angled down like ours . Cheers the pope

earlwb

Great information. Thanks. I never thought of that. I updated my post above about it too.

hllywdb

earlwb
As to the spinner use, yes you can reverse the shaft, ALSO, the shaft does not have to be screwed in tight. I spoke with NV on mine way back and because he threads are so long, you can un-screw it a bit to make it longer with no adverse effects.

As to the muffler, I found if I drilled the 2 mounting holes out just a smidge at a better angle, it mounts just fine. Mine didn't leak, it just bothered me

The carb barrel, that wears in and seats just fine after some use. They tend to manufacture everything to very tight tolerances so pretty much everything has to seat in. I went through the same thing on one of my 25 NV motors.

The rich runs make sense with the glow plugs too. I am still running the same plug on mine after more than a year and close to 150 flights.

hllywdb

Also, do NOT use silicon tubing on the engine, even on the exhaust. The K&S Stay Flex line works the best with this engine, and don't forget the in-line fuel filter.

From the video, you still have some break in to do and some carb adjustments to make after that. Idle still sounds rich, but wait until you get 4 or 5 tanks through it to adjust it.

TampaRC

How much Benol do you add to the gasoline for the correct ratio for this engine?

hllywdb

Hi TampaRC,
There is a chart in the instruction sheet for the mix. I believe someone posted a picture of it a page or so back.

TampaRC

Found it

earlwb

I got a couple of extra glow plugs for the engine, as if you have a spare then the one you are using will not fail. I am sure the glow plug wanted to fail yesterday as it was a holiday here and all the stores were closed of course. So I am finished with running the engine on the test stand and it is running pretty good actually. I was getting around 11,600 RPM plus out of the engine using the Master Airscrew 11x6 prop (it is a black fibre filled plastic prop, I don't know which model though). I'll get the airplane setup for it next.

Now then I do think the threaded prop stub is still a little too short. With the short end screwed into the crankshaft, there is maybe 1/4 of a inch of threads left after putting on a spinner backplate and a 11x6 propeller. I think the threaded stub needs to be about 10mm longer or 1/4 of a inch or so. it reminds me of the Fox engines with their short crankshaft ends where I would want to use a 8 inch pitch prop and there were just a few threads left for the prop nut. With a spinner backplate and the prop I was using there is just barely enough threads there to work, but a few more threads would be much better I think.

I ran the engine quite a lot today, heat cycled it too. And it didn't get all that messy running it, oil residue didn't really accumulate all over it.Now the carb does spit a little but not nearly as much as some other engines I have run though. So the engine is relatively clean running compared to some other engines. Granted it does spew a fair amount of oil out of the exhaust though, so you will be cleaning your plane after using it for the day.

It does get fairly hot though, so it needs some really good oil then. I couldn't measure the temperatures well as the engine top is too shiny for a IR thermometer to measure good. I didn't see any varnish build up on the engine yet. But it hasn't had a few gallons of fuel run through it yet. I was measuring around 276 degrees Farenheit temperatures at the base of the glow plug, but it felt more hot than that.

I took my iPhone DB meter to it and in the close quarters of my back yard, I was getting around 102DB peak noise levels there. The muffler was working OK, the screw heads didn't pop off, but I did not try torquing them down too much.

Anyway, nothing bad happened, the engine ran fine for me, no nasty traits were encountered. It simply just ran and ran.

Here are some more pics of it.

hsukaria

Thanks Earlwb, all the information you have been providing is very helpful and encouraging.

Phoenex

My Feedback: (1)

hillywdb the engine seems to have the performance and design to be a winner, thanks for sharing a lot of information. Since you have direct contact with the company, can you give them the feedback to make the corrections to the muffler and the prop shaft issues? earlwb thanks for the very revealing pictures and feeback on the engine. Ihope NV engines can get this little engine right, they will sell a bunch of them.

hllywdb

Phoenex
Thanks for the kind words. I have spoken with them on both items. They will be looking into the muffler, it is a new design.

As for the prop shaft, it is the same as the AX40, which has been in production for almost 15 years. It is double sided (short and long) and it does not have to be threaded all the way into the crank end. The crank is purposely drilled and tapped deep so those who choose to run without a spinner or use a threaded spinner can do so without having the threads too long. (This would mean using washers to space out a threaded spinner or prop hub) This makes the setup work for just about any configuration chosen. So, just like the nitro 40 and 46, if you wish to use a spinner, don't bottom the shaft into the crank. I have been doing this for years with my AX40's as has everyone else running them. A side benifit is that if you do crash hard and shear the shaft off even with the crank, it is very easy to remove. (Don't ask how I know that)

Hope this helps clear the shaft question up for everyone.

psgugrad

My Feedback: (2)

What type of plug does this engine use? Is it a Norvel exclusive or an OS plug I can get anywhere? Thanks!