Laser 150 V TWIN REBUILD

[TartanMac]

Also looked out my props I am getting close.

[TartanMac]

I just finished running my Irvine 36 and was pretty surprised how well it ran on that 5% Laser fuel. It was old fuel and I have never used it in a 2 stroke and only ran it in a Saito and that was it. I have to say it really is a lot cleaner than Irvine fuel much less smoke. I was running a West throttle pipe which seems to have strong resonance as I was getting 15,100 rpm out of a 10.5x4.5 APC which is from memory around 100-300 rpm down from 10% Irvine fuel that is pretty good as that pipe tops out at 15,400 rpm then stops even if your engine is still making power. The idle was a little rougher than on 10% but could still go down to 1,900 rpm but I think it was because that prop has light blades my 11x5 S2 M/A gives the same rpm as the 10.5x4.5 top rpm but is physically heavier and obviously larger diameter so I think it would have been a better test prop but all in all The fuel seems perfectly good to use and am very happy to use it in my 2 strokes my MVVS I think will love it.

I thought I would mention this for anyone that has not used it and looking for a comparison.

I would like if someone could tell me about why manufacturers insist on castor as I have 2 engines where the manufacturer insists using castor my Novarossi 91CR and my Moki 61LS the moki manual from Just engines says damage will occur if not using 20% castor. The pistons in both these engines look unique and cast but that is all. The 91CR says use 20% oil 50% castor 10% nitro I would like to use the laser fuel in the Moki I don't want either of these engines getting gummed up I don't care about the MVVS it is just a work horse I got for £14 but the other 2 are rare and irreplaceable

[Jon H]

My OS 15fp instructions state that you should only use 20% castor but I run it on the laser 5 and it has never run better.

I doubt they would have any problem with it but if they are irreplaceable then I can understand why you wouldn't take the chance. Any other engine from about the last 30 years will be fine and there is a chap at my club running a 180 moki with laser 5 and its no problem.

[Jon H]

Oh and the laser mix on the left in your photo is straight and has no nitro at all. laser 5 has 5%

[Jon H]

Oh and the laser mix on the left in your photo is straight and has no nitro at all. laser 5 has 5%

[TartanMac]

It looks better with the black but only because they were looking a bit rough. I think it looks a bit out of place I did not do the carbs as they are not smooth and the black gloss would show up the rougher cast parts so I think I will leave them. The mufflers are small so it is not bad but I think a polished or original blasted muffler is best. I do like these mufflers though as they are very compact.

[Jon H]

very nice...but does it go?!

[Gordon Whitehead 1]

That's a lovely looking machine. I had one of the early Laser 75s (= one half of your engine) in a 55in span biplane aerobat I designed especially for it and it really was a powerhouse. Unfortunately the grub screw fastening for the silencer and carb was a weak point and the carb and silencer frequently came loose due to vibration. Maybe I didn't tighten them enough but I did screw them up to the point where I felt that the next twist of the key would strip a thread in the head or bend the key permanently. It was a right royal pain with a cowled engine. Eventually, and well before the current clamp system evolved on production Lasers, I made my own admittedly crude clamps which cured the problem.

If your not going to throw your 150-powered plane around in the sky doing chain-mail aerobatics with lots of throttle changes then maybe you won't suffer the problem, especially as the vee vibrates less. I never tried thread lock and maybe should have done.

The foregoing isn't intended to rain on your parade as the 75 was a lovely engine with which I had lots of really good flying, but mention it as something to look out for when you begin running your 150.

Gordon

[Jon H]

no need to pull any punches Gordon. The grub screws were pants, that's why we changed them!

[Gordon Whitehead 1]

No problem Jon The current clamp system is neat and foolproof, a reliable system essential for keeping the carbs secure on the vees.

Those dinky mufflers look the bees knees. The 150 will sound lovely through those

Gordon

Edited By Gordon Whitehead 1 on 21/11/2017 22:35:54

Edited By Gordon Whitehead 1 on 21/11/2017 22:37:28

[TartanMac]

Posted by Jon Harper - Laser Engines on 21/11/2017 09:22:16:

very nice...but does it go?!

I should find out tomorrow got 2 slec 9oz tanks 1 still has the old line and clunk inside it but my Irvine 36 ran well on it. I have a sulivan 24OZ one I got out my old Sundowner today also as a back up. I got another LC3 plug so If one or 2 of my plugs fail I have 2 LC3 ones to use. I will follow your instructions on running it for the first time Jon I have set the low speed needles half way across the spray bar. I will have to hand start it as I don't have an electric one but should be ok looking at other laser engines being started if I choke it correctly and don't flood it.

I could start my Enya 1.20 by hand consistently after a few goes which is a scary engine to start by hand I think the 1.50V will be easier but will use a pair of ignition leads. I started my enya with my prolux heater and it got stuck on it I had a 16" prop on it and a full 24OZ tank and I could not reach the throttle to cut it out I was standing there with the glow attached thinking this is a bad position to be in.

Yeah thanks Gordon I don't really know what to do about the grub screws but sounds like I will need to think of something. I heard that burnt glow fuel out the exhaust will eat thread lock but I have some I will give it a go whilst running it on the bench but by the sounds of the trouble you had I think I will need to come up with a long term solution too with a set of clamps.

[Jon H]

you should be able to start it with the backflick method if the engine is well primed. The LC3 is not a plug i would recommend but it should get it going without too much trouble.

As for the enya, i have a 120 4c (the little 120) and a 155R. Both are great engines but can be pretty nippy if not treated carefully. I heard a story on another thread about a 155 shattering a cast ali spinner on a kickback. A reduction in nitro was called for on that one!

[TartanMac]

Well I managed to get this engine running after quite a lot of hassle due to the ignition. I got a shot of a starter and it needed it. I could not get the glow plugs to light up bright I was using a prolux heater and a 12v lead acid battery I think it was the way I wired it up but I finally got it sorted by using a AAA battery cage and soldered the ignition lead to it and screwed it to my bench. One of the jets somehow got blocked and I just could not start it by hand I used the starter and a fresh battery and it fired up. Wow it really sounds very different.

I was a bit intimidated as I only had one nut on it holding the prop on and that was all that there was space for. One of the cylinders had a lot of fuel coming out of it and I thought I hope that prop does not come off lol. I have to say though the sound kinda sounded strange to me at first as I thought it was only running on one cylinder but after feeling what was coming out the exhaust which was just oil not raw fuel I though nah it's on 2 cylinders so I revved it up to mid throttle back and forth and leaned it a bit and got a better sound to where it sounded a bit crisper and took it to full for a split second to see if it was way too rich and what do you know another problem the left fuel tank started drawing air in the line so I pinched the other to quit it and stopped it. and that was the test run about 2 mins running. I was just starting to lean the top end and get a better sound too. But it runs Jon and by the sound of it from low revs it pulls off a slow rpm very well I think these liners and rings might be ok but I will test it tomorrow again and lean it to max for a split second and richen it up slightly I did not get that far but when I shut it down the cylinders were not hot and one was cooler than the other but I am happy it runs I think I need to look at the carbs as I think one is opening a little more than the other.

I have to say it is not as loud as I thought it would be but what a rip you get off it sounds good at mid speed and like a motor bike I am kinda sick that I did not get to get the mixture at a better setting before that problem hit. I did not have a good video recorder but this weekend I will borrow someones phone and get some video of it running it is powerfull though Jon it did not seem to struggle revving from mid throttle upward with that 16x8 carbon prop

[Jon H]

Excellent work tartan, i look forward to seeing a video of the beasty in action.

Do not be too worried about running it rich. If the cylidners are cold then its too cool and you need to warm it up anyway. If its too cold it wont run in correctly on the new rings and will loose compression once you lean it off and warm it up. Your 2 minutes wont have hurt it, but next run get it up to at least 90% of optimum tuning and make sure its up to a good temperature.

When it comes to temperature remember the following:

If its cool enough to hold then its too cold, if is cool enough to touch but not cool enough to hold then its probably about right. If its too hot to touch then you are likely in trouble!

From the sound of it your slow runs are very rich. Lean both by a turn and start again. On the ST carbs the slow run needles change the main needle setting so open them half a turn too. Once its running, get it to full chat and lean off a cylinder until the revs drop. Open that cylinder 1/4 turn and then lean off the other. Then lean/richen the first back and forth until it sounds crisp, then do the same to the other.

If the engine starts to sag a little having been held at full power for 20 seconds or so then its a little too hot. DONT open the needles, just throttle back to 1/3 or so, run for 30 seconds then give it another blast. Until the engine is in the air cooling is not 100% so it cant be expected to hold full power all day long. I might see if i can dig out my 150v and give it a run. Its not as pretty as yours though!

[TartanMac]

It is not gonna be pretty for long . I don't know where it leaked from but it seems like oil not raw fuel but it could have came out the front bearing or maybe the front housing or the cylinder. The other side is fine but I did choke it a fair bit tying to hand start it so maybe it has something to do with that. The heads are clean and what I did notice was no oil coming out the valve guides from the rocker area. I did make a mistake by forgetting to oil the rockers so just aswell I never put any real running on it.

I think your right about the slow running being rich I started the engine 3 turns out on the main needles as it did not start on 2 turns but I think it was my ignition. When I run it I did turn the needle in at mid throttle 1/2 a turn and I heard that distinct Laser exhaust note come in a bit just faint and heard the spacing in the firings a bit more clearly. But dropping the revs it kinda went away. I did'nt think about the needles when putting the tanks on I will have to change them.

I will watch the temp closely when running it next time and will just go straight to tunning the main needles. This engine seems really stable I did not get any knocking what so ever no hint or sign of it. You should give yours a run Jon mines will probably be covered in oil very soon. One thing I did notice is that when I thought it was running rough it was weird as I put my hand on the bench to feel any vibration and at half throttle there is none. I have never experienced that with any other engine.

[Denis Watkins]

I still find it odd to see the 4 stroke run without pressure

The tanks clearly show no pressure attached

And Laser recommend no pressure

Yet am certain if the motor was mine, I would routinely connect up for muffler pressure.

Why not guys?

[TartanMac]

I would prefer not to use it Denis if I can get away with it. You don't get your fuel heating up no contamination. But on a test bench I doubt I will need to use it. And I am not sure if I will need it in my 1.20 size Super Sportser as I don't want to fly it hard more like a low wing trainer to get back into flying. I don't really want to drill holes at this point either as I don't know if I will use twin tanks or a single. 2 tanks 2 lines 1 tank 1 line. I also think those mufflers look great without them. But if I feel I need pressure I will try to make a bolt the one you see in the centre of the muffler and double it up as a pressure nipple.

[Ron Gray]

Whilst I am relatively new to Laser engines I can confirm that on my 160v in the Wots Wot XL I haven't got pressure pipes attached and I can go through the whole Clubman Aero routine without a hiccup from the engine. So that's inverted, Cubans, Bunts, Spins, Stall turns and throwing in some Knife Edge flying too. So on the basis of that I would say that Laser's recommendation is correct!

Edited By Ron Gray on 23/11/2017 22:26:53

[Frank Skilbeck]

Posted by Denis Watkins on 23/11/2017 20:08:57:

I still find it odd to see the 4 stroke run without pressure

The tanks clearly show no pressure attached

And Laser recommend no pressure

Yet am certain if the motor was mine, I would routinely connect up for muffler pressure.

Why not guys?

There is no pressure connection on the silencer for one, and two they never seem to need it so people don't bother with the hassle of modifying the engine. One thing my Lasers (and they are very old ones) are quite insensitive to needle settings, my ASP91 and TT 75 fourstrokes only need to be one click out, but my lasers are not so critical. My 30+ year old 61 is currently turning a 14 x 6 at around 8400 rpm.

[Jon H]

The 61 is a monster engine. You can get 1.4hp out of those if you make a little effort.

The goo on the case is likely thrown out under the liner. Don't worry too much, once you run it up to full power and get it up to temperature the heat pulls everything together and they bed down nicely.

The fuel pressure argument has gone round and round but basically you don't need it, so don't bother

[TartanMac]

Well I ran my engine again but only got another few minutes probably 3-5 on it. Got it running and thought it sounds weird so tried to lean the right cylinder I screwed it shut with no change and thought it is not even lit. I set the needle same as the other and changed the battery for the right cylinder. It fired up on 2 cylinders then I revved it to around 4K then took the battery out and disconnected the other glow battery and I heard the left cylinder drop off that was the one I was standing next to so now I know what it sounds like. I re attached the heater and heard it fire up. It increased the revs a lot so I just went to full throttle straight away then tuned both high speed needles it was like Frank said above they are not that sensitive but I got them pretty good I did not want to hold full throttle for that long so I leaned the left till it droppped in revs went back to optimal then richened it around 1/4 turn then did the same with the right. I was not sure the 1/4 turn dropped the revs much but then I went back to around 4-5K the left cylinder I could tell was rich on the low end I felt both cylinders and they were pretty warm and would say from Jons description about right then I went to full throttle and could tell the left cylinder is rich as it was not smooth on the way up. Checked temp again straight after full throttle and it was good. I tried to adjust the low speed and got burned by the muffler the mufflers were really hot lol. The tanks get in the way but it was the clip around the needle that got in the way of adjusting it I need to turn it 90 degrees as it is only accessible on full throttle really. I thought just tach it on the top end and keep temp in it so full throttle took a reading and got 8,600 rpm then it touched 8,700 rpm on the Carbon Mejlik 16x8 so I backed off down to around 4,500 and thought drop it really low before I lose the left cylinder and it went down to 1,900 rpm I was like Wow and I got that classic laser exhaust note then the left cylinder dropped off and it idled at 2,200 rpm which stunned me I got the Laser 75 single exhaust note also very nice lol. but then it just quit.

I left it at that and I'm going to move the tanks back and rotate those clips and order another remote needle assembly. I'm convinced this is going to perform very well but will still keep at it for now till I can get it tuned with a bit more precision I suppose only then will I see exactly what kind of engine I have but I was pretty impressed at what I got today. I did turn the low speed needles in like you said Jon a full turn before I ran it. I was checking temps and it never got too hot to touch but did get temp in it so I would not hold it for too long but it was cooling off at low speeds probably because of the rich setting.

Those 75 singles must have a lot of torque as on one cylinder it was still running on that 16x8. at low speed and turning the other cylinder over.

[Denis Watkins]

Off topic a bit TM,

But your photography is brilliant

It does look like you use a real camera and not a phone

[Jon H]

you are seeing good revs there so top end is fine. as long as the revs down sag at the top end you aren't stressing it so do not be afraid of giving it some welly. It should idle at no more than 2000rpm

[TartanMac]

Posted by Denis Watkins on 24/11/2017 17:40:31:

Off topic a bit TM,

But your photography is brilliant

It does look like you use a real camera and not a phone

It is actually a phone that I borrow as mine is not as good but it is a great spec for a phone. 20 megapixel 1080p @60fps. My sister got a Huawei mate 9 that thing is amazing for photos I think it also has 20 megapixels but it has a very nice screen I think the screen is 1080p it looks amazing. It is funny you ask as I am looking at proper cameras. I would really like a nice one but they are pricey £350-£600 for a really nice one plus accessories. The phone is good but sometimes it starts light on the screen then goes dark slowly then it won't focus on what I want then if you look at the fins in some shots they are nowhere near as shiny as they actually are. On page 2 if you look at the exhaust pic on the right cylinder on the inside that is actually what they look like in person at the angles I took the shots of the cylinder fins from. when you don't have direct light on them it pics it up but it is tricky to get it like that. I tried a video with it on my Irvine 36 with a genesis pipe but it did not sound the same even with my good 2200mw power 18-25000hz frequency response earphones it was not really that good mainly because of the sound but also it kinda looks like the movement is delayed very slightly sometimes. I think the mic does not have the range for sound from an engine and the processor tries to manage it and gives a higher toned less bass sound. But for a phone it is great.

[TartanMac]

This is not a laser cylinder but since I mentioned the 41 4c enya I will post it. I cleaned the cylinder up with 400 grit and oil till I got it fairly clean but I found vertical scratches in it and there is a lot of them all round the cylinder some I can feel them with my finger nail. There is a little pitting also. I took 3 pics 2 showing scratches and 1 showing the result of the 400 grit I think the 400 grit finish looks ok but looking at those scratches maybe it was not the piston ring in the first place or just wear on the steel liner. It was very difficult to take photo of both the reflected shiny angle and non reflecting dull angle it does not really give a sharp accurate image but you can just see the deep scratches is this what a ruined cylinder looks like ?

I left my Laser 1.50 on a matt and it leaked out oil from the front bearing there was a large pool. I fitted new crankshaft and drive gear bearings before I built the bottom end but I just assumed the bearings that were in it were factory ones the front one is a metal shielded one is it supposed to breath through the bearing a little ?