Mike, I saw them in current issue, but surprisingly have not seen UK source? The nearest one was in France? Where did you get price in GPB from?
I also saw some more brand new P.A.W. and CS, not to mention endless supply on ebay . Only yesterday I missed out on ED Racer...
Jon, yeah, now the sound was much different than in my first vid of it running. I need to sort out a bit more stationary test rig as my current one tried to depart when I finally found the sweet spot .
Once again thank you for pointers gents, I appreciate them a lot.
I do realise bigger prop will have more momentum, but I just didn't want to wait for it to arrive in the post and that 7x5 is not bad at all regarding start up. I will get more props soon anyway as this is not the only engine I play with, I want more diesels in my collection
I was sure I have put the engine back to one piece exactly the way it was, during strip down I marked positions of head, liner and piston with black marker and then sharp blade, as marker didn't quite work on oily surfaces . Anyway, today after work I had close look at it and took off the head for a moment, to correct alignment of the ports. It wasn't much, but I thought it's worth a try.
NVA was cleaned yesterday, but I did clean it with carb cleaner, just for piece of mind. Then went outside and had some fun with positioning the tank as she wasn't picking up the fuel correctly, once that was sorted I started to flick again. First attempts were rubbish, far too rich again. So I loosened compression, closed the NVA a little, primed and boom, that's the result
Turns out there is nothing wrong with the engine. One particle of sand and too eager operator resulted in very poor performance, but it's all good now. In the video she still doesn't run to full potential, simply cause I was unable to tweak it with phone in my hand. That run was also a duration of entire fuel tank, well without 10-15 seconds for getting the phone ready to record. When I didn't record, engine was running better and quicker. Needle finally had some effect on the engine too.
I know it's not enough to change my forum nickname to Eifflaender, but hell, got it figured out .
Once again thanks to all who contributed to this thread. Wouldn't have done without you!
I found info about prop sizes on P.A.W. website, which later has been confirmed here. I still do agree it is small, but if no harm is done to the engine, I'll stick to it for now. I'm not touching prop with my fingers anymore, unless the engine is not being run of course.
Now the question is, how do I set the spray bar? I know Engine Doctor did say it, but I have to shamefully admit I didn't quite understand. Facing away from crank, does it mean that hole has to point up? Or perhaps left or right?
I'll make a gasket out of cereal box - if it works on full size motorcycles, it will work on little P.A.W.
I have contacted them by e-mail and while I await response, I had a quick look at NVA. Guess what I found . Jet was blocked by something similar to a grain of sand. Looking from pilot's position, it was more on the left side of the spray hole, which would lead me to believe that needle might have been pushed to one side a bit and that resulted in rich running and no response to adjustments.
Should have done it before, but I expected the NVA to be somewhat more complicated to take apart. How little do I know...
I'm eager to go out with it now, but will wait till tomorrow . Next update about 3-4pm, when I get back from work.
In the meantime I also bagged another Cox on fleabay
I did precisely that and it is possible to close the valve fully, then when I open it it all seems to work. However needle itself is very loose on the thread, which I mentioned earlier. I cramped it little wth pliers but it still seems to be too loose and can adjust itself . Tried short lenght of tubing on the needle and it did stop it rotating, but didn't change running at all.
You mention gaskets, I have not seen even one on this engine....
it could be the case, but I find this oil sort of difficult to wash off and my cigarettes taste like fuel later. I use only one glove though, hope engine will forgive me at some point .
Getting back to rotating comp screw, it was just at the edge of it pushing against contrapiston - compression setting was marginal, but felt nice and bouncy. I am sure that engine is assembled the way it should be, if I put the liner in upside down, exhaust ports would be inside, behind cylinder head walls. Now the liner is not going all the way up in the head, but it's exactly the way it was before. As a result, comp screw has a bit of travel before it touches contrapiston, but then again, all seems in order.
Sadly I don't have bigger prop, but I think my diesel flick is getting better every time I start it . I lost somewhere all my props from few years ago, all I have now are 6x3 Cox props, 5x4, that 7x5 APC, 6x3 APC and 11x6 Zinger.
I will contact P.A.W and see if I can pick some parts up from them, I only live about 45 minutes away so weather permitting, I could go for a rideout .
I know it can run ok and it will.
Fair point about silicone in the system, but I'd expect blocked spray bar to cause lean running? Like blocked jets in standard motorcycle carb?
yes, you're correct, by the end of vid there was no fuel left in the tank.
Since yesterday I have used half of the D2000 small can, I went through all possible combinations of NVA/comp screw, and I mean all of them. NVA from fully closed (then engine didn't run of course as it is possible to fully close the valve) to NVA fully open, in fact it was open so much that needle just fell out and there still was no change in running! The wastage of precious liquid through venturi and exhaust continued as if nothing had happened.
I tried to start it with needle open anything from 1.5 turns, in 1/4 gaps. No joy. Tried small adjustments, tried big adjustments, 1/8th of a turn, 1 full turn and more, still nothing. It seems that only way to keep it running is finding that sweet spot with comp screw.
Another thing, engine seemed to run a bit better with only marginal compression, in which case tommy bar was turning freely - that would explain presence of comp lock.
Can I still order spares for this engine? Think it would be good starting point to get new NVA and then see what happens...
The lock will go back on, but I will have some fun with it before, my dremel is eager to do some work finally
Spent few hours with 1.49 today and I have very mixed feelings.
Needle valve still has no effect as such. Engine either runs or not. When it does, it spits a lot of fuel out of cylinder as well as venturi - like on last video.
However, I do know it can rev much quicker as it did few times today. Only short, few second bursts, but she is capable for sure. What I've noticed, She only picks up when tank is nearly empty, on full runs like a bag of spanners.
Have a look, the only one I managed to record
As you probably noticed, I didn't touch NV on this vid as like I said, it has no effect on the engine running, the only way to increase or decrease RPM is comp screw.
When she quit, tank was dry.
Today I tried to start it on much lesser compression than yesterday. She did, but didn't run so effectively I got back to starting point from yesterday.
Two things that bother me much is that ineffective needle and much better running on nearly empty tank. I did read instructions and placed tank just behind the engine, in line with venturi, when engine doesn't run fuel doesn't flood it, it slowly backs off to the tank.
I am nearly there, just missing some tiny detail...
If I kept filling up the tank while engine was running, I'd run out of the fuel I have. In total I burnt about 4-5 tanks (small ones, not sure of capacity).
It didn't stop imediately, I should be more precise. An adjustment of compression caused it to slow down and then stop, but was recoverable. Adjustment to the needle was like stick in the spokes so to speak. No effect and then sudden stop. It is worth mentioning that needle itself seems to be loose on the thread, it almost wobbles. Never saw needle acting like that...
Just finished having fun in the back garden with two engines - took .10FP for final tweak and of course P.A.W. OS is all sorted and ready to be cleaned and installed in the model once built .
Now to the P.A.W. First impression was absolutely positive, but that diesel flick is so different to glow engines. I filled the tank, spun engine few times with blocked air intake and started to flick. At first nothing, so increased compression, after few clicks she started to sound more and more promissing and soon fired up. That sound and that amount of smoke were amazing .
It was my first time ever running model diesel engines and I know I'm hooked . There is still few things I need to understand, but it was worth the wait for sure .
I think I may need to have a look at NVA as needle seemed to be completely ineffective, engine was either running or not and no changes were noticed, apart from dying engine of course. Here is short clip of the setting that would let me run it forever, however I think she was running too rich and that I could squeeze much more out of her.
Once again thanks for advice regarding contrapiston. Without your pointers gents, it would be a while before she'd run (if at all).
PS I did not need the comp screw lock, engine runs just fine without it.