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Morris gas conversion experience

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Ted Khinsoe04/09/2019 14:33:34
11 forum posts
18 photos

I have a Magnum 160 twin new I’m contemplating converting to petrol using the Morris mini motors kit. I’d appreciate any feedback.

Jon - Laser Engines04/09/2019 14:44:54
4843 forum posts
180 photos

My experience has been very poor.

Many customers return their engines to me for conversion back to glow as they didnt work following petrol conversion.

My own petrol development has demonstrated clearly that its really not as simple as carb swap and ignition. At least not for the level of performance that i deem acceptable.

flight104/09/2019 14:50:35
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630 forum posts
33 photos

I know one person who converted an asp version and the big end siezed, made a wet sump with caster in it, which he replaces after each flight session and is still going now a few lears later.

why go petrol you will get less power out of it? and it will run a lot hotter so cooling is very important with baffrels needed directing air flow etc.

I have one and it is very reliable on 5% and has a low oil content fuel with fully synth oil to reduce any mess and I have not lost just one cylinder on it yet

 

Edited By flight1 on 04/09/2019 14:52:17

Manish Chandrayan04/09/2019 16:01:53
597 forum posts
70 photos

I have an ASP 160 converted to ignition and run on glow using CH Ignitions supplied parts. I had issues with one cylinder dropping and hence the conversion.

Ted Khinsoe05/09/2019 04:36:54
11 forum posts
18 photos
Posted by flight1 on 04/09/2019 14:50:35:

I have one and it is very reliable on 5% and has a low oil content fuel with fully synth oil to reduce any mess and I have not lost just one cylinder on it yet

What oil content do you use?

I was mainly concerned about reliability on glow but I guess onboard is a reasonable option.

Thanks for the feedback

cymaz05/09/2019 06:42:29
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8766 forum posts
1190 photos

I’ve used one of these for many years. Excellent bit of kit. You have to get it from the US though. I thought I had an issue with it a couple of years ago. The customer service was superb- even though I was 1000’s miles away! It turned out a pin had a dry solder joint.

That said, I’d buy another.

Ted Khinsoe05/09/2019 07:42:42
11 forum posts
18 photos

Im in Australia 1000's miles from everytwhere!

Jon - Laser Engines05/09/2019 09:01:55
4843 forum posts
180 photos

I have an ASP version of this engine and my only gripe is the mismatch between the cylinders when it comes to the tuning. My right cylinder always runs rich vs the left up to half throttle. I have never flown it due to a change of plans, but in all my test running its never dropped out at random so i dont think its going to be a problem.

After i changed projects i did set about modifying my engine so it now has laser twin ring pistons and this has helped the compression somewhat. I needs new rings though, i only had worn ones to play with when i rebuilt it.

If i get time i might convert it to twin carb as that will fix everything

Ted Khinsoe05/09/2019 15:15:52
11 forum posts
18 photos

It’s slated for a 1/4 scale L4 Grasshopper so as long as it stays running I’ll be happy.

Piers Bowlan05/09/2019 15:21:38
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1891 forum posts
49 photos
Posted by Jon - Laser Engines on 05/09/2019 09:01:55:

If i get time i might convert it to twin carb as that will fix everything

I would be interested to hear about that Jon, if you get around to it, as I have an ASP160 twin.

Jon - Laser Engines05/09/2019 15:35:32
4843 forum posts
180 photos
Posted by Ted Khinsoe on 05/09/2019 15:15:52:

It’s slated for a 1/4 scale L4 Grasshopper so as long as it stays running I’ll be happy.

that is what mine was for. A friend and i both had models but his crashed before i built mine. As we wanted to fly them together i abandoned the project but kept the engine.

Piers, if there is interest i will step it up in priority from 'one day it might be fun' to 'something for the winter'

One final gripe about the engine is the sound...its awful, or at least it is on the bench. I have two flat twins (160 and 300) and they both sound extremely harsh when unsilenced. My now sold 3 cylinder saito, my 5 cylinder asp radial and OS flat 4 sound fine on straight pipes but for some reason my two flat twins sound really bad so a pair of silencers is recommended.

Piers Bowlan05/09/2019 16:50:27
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1891 forum posts
49 photos

Thanks for that Jon and I will bear it in mind. Like most people I don't like noisy engines. I bought the engine a while back for a President D31 Turbulent for which I hope to have sourced a plan quite soon...

Edited By Piers Bowlan on 05/09/2019 16:51:39

flight105/09/2019 20:10:02
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630 forum posts
33 photos

the asp is not noisy like a 2 stroke engine and if you use a baffled silencer on each cylinder you will find the noise to be very amicable. two asp .60 size baffled silencers with suitable manifolds will do nicely or make your own.

as for fuel I don't know what you use down under but 15% fully synth modern oil works fine, once run in and if you like straight fuel and know what you doing a lower oil content can be used

Jon - Laser Engines05/09/2019 20:41:17
4843 forum posts
180 photos
Posted by flight1 on 05/09/2019 20:10:02:

the asp is not noisy like a 2 stroke engine and if you use a baffled silencer on each cylinder you will find the noise to be very amicable. two asp .60 size baffled silencers with suitable manifolds will do nicely or make your own.

as for fuel I don't know what you use down under but 15% fully synth modern oil works fine, once run in and if you like straight fuel and know what you doing a lower oil content can be used

Quite right. What i mean is other multi cylinder engines have a nice sound on straight pipes but from some reason the flat twins i have experience with sound really harsh. One is an OS ft300 and it was unbearable. I bodged up a pair of exhausts with parts from work and it then purred like a kitten.

As for fuel, 5% nitro and 15% synthetic is my starter for 10 on all engines these days. As the conrods are pure bronze in the 160 you would likely be fine with 10% oil and probably even as low as 5%. I have not yet run mine on anything less than 15% but there is loads of oil coming out at 15 so i think i will go for 10% when i finally get around to using it.

stu knowles06/09/2019 08:44:14
572 forum posts
44 photos

**LINK**

Jon - Laser Engines06/09/2019 12:25:06
4843 forum posts
180 photos

A perfect example of the problems with these conversions. Flat out they can work, but low throttle is usually a mess. From the sound of the idle its only running on one cylinder and you can hear the other two come in as the throttle is opened up.

chris larkins06/09/2019 13:05:40
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208 forum posts
144 photos

**LINK**

Skip forward to about 17mins if you don't want to watch the parts being fitted

Edited By chris larkins on 06/09/2019 13:07:36

Jon - Laser Engines06/09/2019 13:53:21
4843 forum posts
180 photos

I love their enthusiasm, and as it happens it sounds pretty good. Transition is slow/rich but not like the other video.

Its a hefty old unit bolted on the bottom though. Its like another whole cylinder!

chris larkins12/09/2019 04:00:41
avatar
208 forum posts
144 photos

As the Precedent Turbulent was mentioned I thought I'd post a video of mine, it has an SC 1.20 converted to run on petrol. It hasn't been without problems but this was mostly because I was trying to use the original glow carb to start with, the needle was just too sensitive to be able to adjust it properly or get it running reliably. I have since bought the carb kit from Morris which I believe is an RCGF carb, it is now running much better and I have over 40 flights on this setup, it runs on a 25:1 oil mix (4%).

**LINK**

You will see in the video I am using an Evolution 16x6 prop and I'm getting 7800-7900 rpm at full throttle and around 1850 rpm at idle, this may be slightly less than on glow but I doubt by very much, and certainly not enough to worry about on this type of model. BTW I still have glow engines (Laser and others) so I am not saying petrol is better in all circumstances, here is a list of the pro's and con's (so far)

CON's

  • The cost of the parts
  • Maybe a slight drop in rpm at full throttle
  • It ran hotter so I had to add cowl baffles

PRO's

  • Cheap fuel, around £7 a gallon, it also uses less than 1/2 the amount so it's 1/4 of the price
  • Easy starting, less equipment, all I need is model, TX and starter (it will hand start)
  • Low reliable tickover
  • Absolutely no exhaust mess, so no cleaning
  • No fiddling with the mixture, I haven't touched it for around 35 flights
chris larkins14/09/2019 10:54:50
avatar
208 forum posts
144 photos

I was recently messing around on my lathe and decided to have a go at making a magnet ring for another petrol conversion that I have in the pipeline, the one that Morris sells costs about £30 (I wonder how much of this is because it is anodised?), it is basically just a ring that fits over the prop driver with a magnet and 2 grub screws.

I knocked one up for about £2 inc the magnet, I also made a fuel plug from scrap.

I reckon I can get the bits together for around £78, this is £2 for the magnet ring and bracket, £38 for the ignition unit and sensor, £25 for the carb (RCGF), £4 for a sheet of phenolic to make a carb heat spacer and £9 for the 1/4-32 spark plug.

magnet ring.jpg

dsc_0832.jpg

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