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What The Heck . . . .

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What The Heck . . . .

Old 10-25-2003, 12:25 PM
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T.W.
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Default What The Heck . . . .

. . . . am I doing wrong?

In other posts I've told how I've struggled to get my new V-7 engine to spin-up, well thanks to your help, that's "almost" cured now. It seems to me that the piston/cylinder fit is prety good, even though it will still "stick" at TDC occasionally (which I think is normal). It won't spin on my 1/2A starter motor, but my normal aero starter does the job fine, now that I've made an adaptor to fit the engine's starter cone

To get this far I've spent a very long time, through quite a few sessions, turning the engine over with my electric starter, with plenty of light oil slopping and splashing around the bore, and without the head fitted. Since starting to do this (and as Darth hinted-at in another post) I've had to re-charge my 12-volt starter battery a couple of times, so this wasn't achieved easily nor quickly

A few hours ago I reached the stage where I got the engine to spin on the starter with the head and plug fitted and tightened-down. Great, now I could think about firing it up!

The glow plug glows "really bright," I drip one drop of fuel into the carb (the tank's empty because I just want to hear the engine pop a couple of times when I spin it up with the glow-start attached) . . . . and once more it just won't spin! But it will spin without the glow-start attached

OK, leaving the glow-start attached I loosen the head, spin some of the fuel out of the engine, re-tighten the head and try again, without adding any more fuel - the engine spins but it doesn't pop. I add one single drop of fuel down the carb and the engine won't spin, sticking at TDC again

I'm using a Kavan starter, which is geared-down and which has no trouble starting any of my other engines, which include an OS .61 FSX, and I just can't imagine why this starter cannot spin the V-7 up. OK, the Kavan starter may not be spinning fast enough for the engine to fire, but why on earth won't it spin?

I've also tried getting the engine spinning with the head loose, and then tightening it down while it's spinning, but with a drop of fuel and the glow-start attached it stops at TDC every time. Doing the same without the glow-start attached the engine continues to spin ok though , so I don't think I have too much fuel in the chamber (don't get the idea that I'm wearing the engine out running it this way, these attempts are all over very quickly). It seems that attaching the glow-starter "locks" the engine at TDC - but why?

I'm really losing my patience now and I'm thinking that maybe I should send the engine back where it came from. But then again, I had to pay £43 just to get it here in the first place, what with post & package, import duty and handling fees - and no-doubt I'll have to pay that much again for a replacement engine too - plus the return postage. But what else can I do if I can't get it to run . . . . ?

Any ideas?

Tony
Old 10-25-2003, 12:49 PM
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lyk2fly
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Default RE: What The Heck . . . .

Tony, patience my friend......mine acted the same way. Once it started and actually ran a while it was fine. The cylinder/piston fit is still tight, the compression is still high, and the fuel expansion is the straw that is breaking the camel's back. Keep on trying it with the heatsink loose, once it fires tighten it back up. After a few times it will be alright. I broke mine in right on the heli. Rich then lean, rich then lean. I believe it'll all be fine. At least I hope so.
Mark
Old 10-25-2003, 01:25 PM
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Default RE: What The Heck . . . .

Hi Mark - thanks for your "words of comfort!" They help to reassure me that the little bu**er really will fire-up - if I just have sufficient energy to keep trying for long enough!

Tony
Old 10-25-2003, 02:04 PM
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Default RE: What The Heck . . . .

hey tony, I don't know what is going on with your motor, mine did start right up and has been going strong. It sounds like you are going about it right from what I have read. Keep at it , I am real happy with mine so far. Alan
Old 10-25-2003, 02:34 PM
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Default RE: What The Heck . . . .

Thanks for this Alan. I'm really glad your engine is ok and I will keep on trying with mine

I've just never come across an engine like this one before. It seems really strange (not to mention frustrating) that I can't get it to fire and run. But the engine has a load of compression, so I'll just have to console myself that it will be ok - if I could just get the thing to start-up

Since I last posted I've tried using a drop of 30% nitro (which I used in my V-6) but even the extra nitro made no difference. I'm thinking I'll try using a drop of diesel fuel tomorrow - with this much compression available it ought to pop - at least once, maybe!

Tony
Old 10-25-2003, 03:00 PM
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Default RE: What The Heck . . . .

Tony, I know you've said that when you add fuel it won't spin .. if you can spin it without fuel then I say add to the tank and spin it till it sucks the fuel by itself. Maybe this will help. I just came in from a few more tank fulls of flight and at one time it flooded and it took foe ever to start.. Then I noticed if I held the starter on too long it prevented me from starting. I had to hit it with the starter and remove it fast then it caught and ran. Don't know if this help or not.. Good luck and keep us posted, by the way isn't it night time for you ????? Alan
Old 10-25-2003, 03:36 PM
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Default RE: What The Heck . . . .

Thanks again Alan. I'll try what you suggest - tomorrow. You're right about it being "night-time" here. Right now it's 9.30pm so it's too late for me to continue trying to fire-up my engine now

Maybe I'll enlist the help of my wife tomorrow too - what with holding the heli, holding the starter motor, loosening and tightening the head, applying the glow-clip and twiddling the needle . . . . this little engine seems like it takes "team-work" to get it started

Tony
Old 10-26-2003, 06:20 AM
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Default RE: What The Heck . . . .

Last night I left the engine soaking in light oil and this morning I spun the oil out, fitted the head using 7 washers (I found an extra one!). I adjusted the needle to 1-1/2 turns out, put some fuel in the tank, attached the glow-clip and applied my starter motor

The engine spun-up ok, but no sign of life - due to no fuel getting through. I open the needle 1/4 turn and applied the starter again - nothing for a few cycles, and then the engine stops at TDC

I turn the needle back in 1/8 of a turn, remove the head, spin the engine up to clear the excess fuel. Refit the head, apply the starter motor and the engine spins-up ok. I apply the glow-clip and try spinning-up the engine again - it stops dead at TDC (I'm going to bend the con-rod if goes-on much longer!)

I turn the needle in another 1/8 and go through the above again - the engine spins but there's no pop (no fuel's getting through at all I guess). I turn the needle back out 1/16 of a turn, enlist the help of my long-suffering wife . . . .

I get the engine spinning and then my wife applies the glow-clip - the engine stops at TDC as soon as the glow-clip touches the plug. So the glow plug's igniting the fuel and causing the stoppage, but the engine hasn't popped!

I follow-on from this trying other things, like getting the engine spinning with the glow-clip attached, but with the head loose, then I tighten the head as it's spinning - the engine stops at TDC with no pop at all

Is it possible that this engine's timing is wrong? Is it possible that the exhaust valve cut-out is in the wrong place? Are these engines made "by hand" or by CNC?

Anyone have any ideas?

Tony
Old 10-26-2003, 08:07 AM
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fiat
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Default RE: What The Heck . . . .

Tony from what I have read these motors are only hand fitted not hand machines. I remember that my motor did hydro lock the very first time I tryed it but I thought I just flooded it so I loosend the head and let the fuel out that was that. It sounds like this is your problem too but every time ? Hmmm. The crankshaft has a cut out in the front that draws fuel in ,I wonder if it's posible that this part of the crank "twisted" or if assembled wrong ? I do not know if the cranks are machined as a whol or put together from pieces as some other small engines are . Have you tryed sending e-mail to lite machines from their web site ? I wonder if they would pick up all the shipping costs if need to return the motor ? They are very nice helpful people it's worth a try e-mail is free. Go to" contact us " on the web.. Hope you get going soon I am haveing a little problem myself right now with glow plugs arggg.. Alan
Old 10-26-2003, 09:16 AM
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Default RE: What The Heck . . . .

Tony, will the engine not fire with the heatsink still "somewhat" loose? Mine would fire with the glow stick on but with the heatsink loose. After the engine started then I would tighten the heatsink. The loose heatsink allowed the engine to turn over and start. Just start slowly tightening the heat sink with the glow ignitor on and starter turning. At some point the engine should come to life. I hope this helps,
Mark
Old 10-26-2003, 10:01 AM
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Default RE: What The Heck . . . .

I just sent of an "SOS" email to LiteMachines, so you read my thoughts on that one, and no, my engine isn't hydrolocked. It will spin right up to the second I connect the glow - then it stops dead

I've tried with the head loose and then gradually tightened it as the motor's spinning and it hasn't so much as popped once. It just spins right up to the point where it stops dead

It's as though my starter needs more torque to power the engine through TDC when the glow's energised . . . . but I'm using a very powerful starter, any more powerful and I'm sure I'd bend the con-rod, so that can't be where the problem lies

To be perfectly frank I don't really know what to try next. Maybe I'll have to remove the engine, screw it to my bench, fit a prop and try flicking it over - but I've always had to resort to my starter when I couldn't hand-start an engin in the past. Very frustrating!

Tony
Old 10-26-2003, 10:20 AM
  #12  
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Default RE: What The Heck . . . .

sorry to hear this Tony keep us posted I really want to know what Litemachines has to say... Alan
Old 10-26-2003, 12:21 PM
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Default RE: What The Heck . . . .

Tony, all I know to say is wow!! Sorry to hear it. Maybe the Lite Machines folks can help.
Mark
Old 10-26-2003, 02:30 PM
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Default RE: What The Heck . . . .

Thanks for your support guys, it means a lot to me

This evening I totally gave-up and removed my new engine from my LMH with a view to re-fitting my V-6, so that I can resume flying while the V-7 situation gets sorted out. But once I'd removed the engine I thought I'd try bench-running it - so that's my current plan

I've left the clutch and it's bell fitted to the engine and worked-up a way to fit a prop to the pinion that's fixed to the clutch bell (don't want the engine to rev itself to death if it should fire-up). The engine is now bolted in place and tomorrow morning I'll give it a go

Another idea I've only just had is this: because all(?) V-7 engines stick at TDC unless they're turned-over quite fast(?), perhaps my Kavan starter just isn't fast enough once the glow's energised. The Kavan is certainly powerful, but perhaps it's more about sheer speed than grunt. Anyway, with this thought in mind I've been in touch with a friend who deals in all things RC and have arranged to borrow a selection of used starter motors so I can try them all. Well, you never know, it may work (clutching at straws here, maybe!)

Tony
Old 10-26-2003, 02:57 PM
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fiat
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Default RE: What The Heck . . . .

Tony I do know that the starter litemachines sells for the novel "which I have" does spin alot faster and I have heard of a guy who used to use an aircraft starter but was so frustrated at hard long starts that he got this starter from litemachines and his starting trouble was over. The little starter is less powerful but much faster. Centrifugal force maybe whats starting these ?
Old 10-26-2003, 03:18 PM
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Default RE: What The Heck . . . .

Guys, I use a Hobbico Torquemaster 90. It has always started my vmax6 and 7 just fine......I would imagine that it is slower than the Lite Machines starter. I've thought and thought about the situation and I just can't figure out what's wrong. Tony earier I said that all I could think to say was wow.....actually the words I was thinking of can't be said here......let us know how it goes,
Mark
Old 10-26-2003, 04:15 PM
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Default RE: What The Heck . . . .

Thanks again guys. I forgot to mention that I tried a drop of diesel fuel today too. Normally this will get any engine going, even when it's so cold that the ground's frozen-over. But it made no difference to the V-7 at all

I could be totally wrong here (I usually am!) but I'm pinning my hopes on the fact that my normal aero starter is a bit slow compared to "normal" starters, due to it's gearing. It's a lot slower than my 1/2A starter, but that lacks power!

Maybe I'll make a break-through tomorrow, somehow

Tony
Old 10-26-2003, 04:24 PM
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Default RE: What The Heck . . . .

Tony, tell me about the diesel engines.......do they use normal diesel fuel like big trucks? I've heard about them but have never seen one.
Thanks,
Mark
Old 10-26-2003, 04:37 PM
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Default RE: What The Heck . . . .

Hi Mark, I can't tell you very much about diesel engines as I've never sudied them. I only ever had one of them (a long time ago) and I found it to be very messy, smelly and under-powered. I don't think truck diesel fuel is the same as model diesel fuel (although I could easily be wrong!). These days I keep a small bottle of diesel fuel in my flight box so that I can get reluctant glow motors to fire-up (usually in very cold weather) by using it to prime with. It works really well - except on VMax-7 engines of course

Tony
Old 11-01-2003, 11:49 AM
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Default RE: What The Heck . . . .

Breakthrough! I think. V-max #4, First 3 engines were very tight, EXACTLY like yours TW, and this one is a bit more loose. The other three took for ever just to get to pop or run and then the conrods broke. I just got done starting #4 for the first time and it started easily, within 15 minutes, while the others took at least an hour. The only difference....this cylinder head combo wasnt as tight as the others. I could actually turn this one over with a good finger grip(didnt seem too loose though). I think maybe norvels strive for a super tight fit may be killing the engines conrod with an overly tight fit. I still have to break in the engine though because it was running lean at 3 turns, so i backflushed the needle valve and carb, and I'm out to try again.
*Cross my fingers*
Old 11-01-2003, 11:59 AM
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Default RE: What The Heck . . . .

By the way I use the Norvel 25% fuel and a big 60 size heavy duty starter from Hobby Shack with no problems from either. Once I hear the engine pop consistently I pull off the starter or it will prevent it from starting
Old 11-01-2003, 12:36 PM
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Default RE: What The Heck . . . .

Sounds as though you may have "got a winner" there cherikeered. Good luck with running it in (and don't run it too lean too soon)

I'm about set to give my V-7 another try, hopefully tomorrow. I've now got some freshly-mixed 25% nitro/17% Castor fuel at the ready and have also got a fast-turning heavy-weight starter to hand too. Why don't I try starting it today? . . . . because I've been out shopping with my better half all day, and right now I've just "had enough!"

Tony
Old 11-01-2003, 04:11 PM
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Default RE: What The Heck . . . .

well I just got back from the field and I actually got this heli in the air after two months of replacing engines. I got a about 2 more tanks through it this new engine(5 total), and then it fell from the sky. I checked it out and I know I dont even have to open it up, its the conrod, engine #4 is a goner. The piston doesnt move when i turn the thrust washer. I really thought that this was the one, it ran so much differently and so well but no it is dead now too. ARRRRRRGGGGGHHHHH!!!!!
Old 11-01-2003, 05:23 PM
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Default RE: What The Heck . . . .

I'm really sorry to hear about this cherikeered. It must be really frustrating for you. What on earth is wrong with these little engines?

I just had a short "engine-starting" session. But I still couldn't get it going. I was quite excited to hear it pop (for the first time!), but as soon as I opened-up the needle valve another 1/4 turn, to get a constant supply of fuel to the engine, it became impossible to spin-it up - hydro-locked!

Then, when I turn the needle back in a little, the engine went back to producing the occasional pop. It doesn't even seem capable of producing a couple of consecutive pops - just "one pop" every now and again!

I'll have one last go at getting this engine running tomorrow - then I'll really have to throw the towel in

Tony
Old 11-01-2003, 08:52 PM
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fiat
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Default RE: What The Heck . . . .

I am sorry to hear this Tony, But to tell you the truth I am kinda worried about my new motor "when it gets here". I do want to fly this thing. I suppose if the new motor dies I may keeo sending them back as every one else does. But on the other hand if it continues to blow up then I see no correction in sight. There fore I will probably being buying another type of heli. Alan

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