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Outdoor Free Flight Forum => Power => Topic started by: Manne on February 21, 2012, 10:00:44 AM



Title: Heron 1cc diesel - help needed
Post by: Manne on February 21, 2012, 10:00:44 AM
Hi Everyone, can some body help please?
I have an old Heron 1cc diesel which I am trying to get back from the dead. The last time I ran a diesel was when I was about 13 (many, many years ago. Here's a hint, Ian Smith had not declared UDI in Rhodesia)
The engine has been cleaned and I have managed to get it to fire, but only after priming a little fuel in the port. I do not know what the correct setting for the needle valve or the compression should be. I have initially set the needle valve to 3 turns open and the compression at a point where the engine fires.
Can anyone give me some pointers?


Title: Re: Heron 1cc diesel - help needed
Post by: TimWescott on February 21, 2012, 11:13:48 AM
If it sounds like it's running nicely on the prime, then that means that your compression (and a lot of other things) is at least good enough for it to run.  But if it then doesn't continue to run, it means that there's something wrong with the fuel delivery system.  Given that it runs on a prime, it's almost certainly too lean.  So either you just haven't been adventuresome enough with cranking the needle open, or you've got an obstruction in the spraybar or needle valve, or for whatever reason your tank is not delivering fuel.

If you're confident in your tank, I'd make absolutely sure that your needle valve is clean and flowing fuel.  At the very least I'd take out the needle and squirt some fuel through the spraybar; if it's easy to take out I'd do just that, and make sure that the spray hole is free of dirt.  If you're not confident in your tank, make sure that fuel can flow, then watch the fuel tube going into the spray bar -- look for bubbles, just plain no fuel, etc.

I don't fly diesel engines a lot, but I do always find it a challenge with a new engine to get the right combination to get it started.  Once that's done, though, I've always found it reasonably easy to get them tuned the way I want.


Title: Re: Heron 1cc diesel - help needed
Post by: Daithi on February 21, 2012, 12:03:30 PM
3 turns is normal on the needle - but check that the pinhole isn't clogged up (remove it and soak it in meths or similar - dried oil can turn gummy and that will block the fuel getting through).

Attach a piece of tubing and try blowing through - if your face turns red and nothing happens, that's the problem ;)


Title: Re: Heron 1cc diesel - help needed
Post by: TimWescott on February 21, 2012, 12:53:29 PM
Note that testing the spraybar hole by making sure that fuel will draw if it's fully choked isn't enough -- that hole can be partially clogged and draw fuel up just fine, yet still have a problem with fuel draw.

Blowing air is better.

Disassembly and actually cleaning the spraybar -- if you can do it easily enough -- is best.  I'm not familiar with that engine (the US is culturally backwards when it comes to model diesel engines), so you have to decide if it's worth it to take it apart.


Title: Re: Heron 1cc diesel - help needed
Post by: Mark Braunlich on February 21, 2012, 01:56:51 PM
Might be some new info here for you:
http://www.rcuniverse.com/forum/m_7968234/anchors_7968503/mpage_1/key_/anchor/tm.htm#7968503


http://modelenginenews.org/cardfile/ME_heron.html


Title: Re: Heron 1cc diesel - help needed
Post by: dputt7 on February 22, 2012, 01:55:41 AM
Hi
I had a Heron in a free flight Albatros C 111, It was great until the day it wouldn't start anymore. same thing as yours run on the prime but not enough crankcase compression to keep it running, just plain worn out. Hope that's not the case with yours, one thing amongst the good advice given is to make sure the hole in the spray bar points down to the crankcase if its a one holer or if it has 2 holes they should be horizontal ( front and rear ) Good Luck
regards Dave


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on February 22, 2012, 04:11:08 AM
Thanks one and all for the replies.
Dave, the spray bar is a 2 holer and yes it is orientated across. I hope it is not worn out. I will give it another go this afternoon and see what happens.
Manne


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on February 28, 2012, 10:27:39 AM
After 10 million flicks, a tired arm and only a short run, I am beginning to wonder if the engine is worn out.
Would additional ether in the fuel make a difference?
Manne


Title: Re: Heron 1cc diesel - help needed
Post by: Daithi on February 28, 2012, 11:45:52 AM
I would doubt it very much - the fact that it fires shows that there is ignition.
It does sound as if the fuel just isn't getting into the cylinder. It could be lack of compression and just possibly a rebore may help, but it's not certain


Title: Re: Heron 1cc diesel - help needed
Post by: gossie on February 28, 2012, 03:45:09 PM
Try lots of castor, and more ether........you just may be lucky. 


Title: Re: Heron 1cc diesel - help needed
Post by: glidermaster on February 28, 2012, 04:00:29 PM
Assuming you have fresh fuel, Gossie is right.

If your fuel's old, you could just add a little fresh ether.
John


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on February 28, 2012, 07:25:05 PM
Ok, thanks guys.
In this over regulated society it is going to be fun finding the ether, but who knows, I may find a sympathetic chemist.
Manne


Title: Re: Heron 1cc diesel - help needed
Post by: glidermaster on February 28, 2012, 08:25:48 PM
I believe Bradex 'Easy Start' (for recalcitrant car engines) is almost pure ether.


Title: Re: Heron 1cc diesel - help needed
Post by: TimWescott on February 29, 2012, 09:58:06 AM
In the US, John Deere starting fluid is supposed to be almost pure ether.  I'm not sure if it's sold in the UK (I assume that's where the engine is), or if it is if it's the same stuff.

Also in the US, you can look at the safety warning label and figure out the ether content of your starting fluid, which turns the task of finding one with lots of ether into a tedious task, instead of an impossible one.


Title: Re: Heron 1cc diesel - help needed
Post by: Daithi on February 29, 2012, 10:17:09 AM
Easy Start is high ether content - but it's in a pressurised can and VERY dangerous if you try to open it.

TBH, I'm not convinced ether is the problem here - the fact that the engine DOES fire would suggest that there is enough ether in the mix - the fact that it stops running would lead me to think a lack of compression (and it's not sucking the fuel up)


Title: Re: Heron 1cc diesel - help needed
Post by: TimWescott on February 29, 2012, 11:33:10 AM
To extract the product from any aerosol spray can, grab a pint jar or paper cup or other open-mouthed container that won't melt with the stuff.  Go outside (preferably on a dry, breezy day), point the nozzle at the edge of the cup and into the cup about 15 degrees.  Spray.  Most of the stuff will end up at the bottom of the cup.

This may work better with a narrow-mouthed jar -- but I haven't tried it.

Does the engine seem to run out the entire prime, or does it just splutter and sput, maybe just giving you one weak fire on one revolution?  If it runs out the prime lustily, then the top end is good, and you've probably got compression in the crank case as well.  If it just splutters and sputs, then you may be temporarily sealing it with the fuel, enough to fire, but not enough to go on.

To check for compression, rotate the prop by hand over top dead center.  You should get a definite push coming down from TDC.  The longer you can hold the engine at TDC and still have it push down, the better the seal is -- just a fraction of a second is good enough for glow engines, but I know that diesels need better (and I don't know how much).

I have one (glow) engine that'll hold compression like that for several seconds.


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on February 29, 2012, 07:50:59 PM
Thanks for the input.
Tim, you may have something there. I will try the compression test by using a little heavier oil in the port. That should provide a better seal around the piston, then if it is worn the oil seal would give a good compression, which I compare with a fuel 'seal'.. (We used to check for valve leak and compression in auto engines that way).
I am not sure if any of the ether based starters are available in Aus.
Manne


Title: Re: Heron 1cc diesel - help needed
Post by: Daithi on February 29, 2012, 07:58:07 PM
Oil in the port will give you a false indication (it was an old trick used when selling a clapped-out motor).

With the oil it seemed that the engine had good compression - when you put any fuel in though, it was useless


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on March 01, 2012, 08:45:52 AM
Hi Daithi,
You have a point, I realize that, however it will give me an indication if there is a lot of wear, or am I fooling myself? How else can I gauge the wear factor?


Title: Re: Heron 1cc diesel - help needed
Post by: Mark Braunlich on March 01, 2012, 10:37:02 AM
Manne,
Are you using the attached tank?  Can you get any fuel draw by flipping the prop with or without finger over the air intake?  Try using separate tank and elevating the tank a bit to give you some fuel pressure at needle valve.  You could possibly just use a length of transparent fuel tubing to give you the head of pressure. If you have clean NVA and you're not getting fuel draw, you have a pressure leak in the crankcase.  Make sure your gaskets are good.

Also, is the red anodized cylinder head red or pink?  I've read that the red anodize on some diesels (McCoy) can turn pink with a lot of heat cycling....a way to know the engine has seen a lot of use.

Mark





Title: Re: Heron 1cc diesel - help needed
Post by: Manne on March 01, 2012, 11:06:04 AM
Hi Mark,
I did manage to get the first run with the attached tank, but it tended to draw air, and I aso think that there is a leak in it.
The fuel does draw when I choke the intake. I did install a separate tank and did elevate it, which did help initially but then it flooded so I took it back down to neutral.
NVA? May I ask what you mean?
The head is still quite red, so I dont think it has had too much heat.


Title: Re: Heron 1cc diesel - help needed
Post by: Daithi on March 01, 2012, 11:35:44 AM
One check is to screw down the contrapiston hard so that it actually stops the piston from moving. Then back it off a couple of turns, turn the engine by hand and see if it moves the contrapiston and then check to see how far it actually moved (if it fails, then there isn't enough compression)

It sould be able to push it back a couple of turns on the compression screw


Title: Re: Heron 1cc diesel - help needed
Post by: Mark Braunlich on March 01, 2012, 12:26:46 PM
NVA= needle valve assembly

or
Normandy Veterans Association

or
North Vietnamese Army

Take your pick ;D


Title: Re: Heron 1cc diesel - help needed
Post by: Ployd on March 01, 2012, 04:56:46 PM
Hi Manne

I see from your profile you are located in WA and not far from Perth so you should be able to contact the local control line fliers regarding a source for ether, I will try and dig up Charlie Stone's contact details and he should be able to help with your engine problem.

Ployd in OZ


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on March 02, 2012, 04:01:03 AM
Hi Ployd,
Thanks for the help. I have been in contact with Phil Trueman at TARMAC and we have been communicating about it.
If Chas Stone can help, that will be great. I will look him up on the AWA website.
Regards,
 Manne


Title: Re: Heron 1cc diesel - help needed
Post by: Ian Easton on March 02, 2012, 10:08:05 AM
Make sure there is not an airleak on the back plate. That can cause running problems. I think the Heron may actually have a very thin gasket there. Many times too the back plate can get warped from overtightning which can cause an air leak.
Ian


Title: Re: Heron 1cc diesel - help needed
Post by: Daithi on March 02, 2012, 12:18:41 PM
We used to make gaskets from ordinary brown wrapping paper - smear oil on the crankcase, rub the paper on and there's the template - just cut it out VERY carefully (pierce the screw holes with a pin and the screws themselves will ream them out)


Title: Re: Heron 1cc diesel - help needed
Post by: TimWescott on March 02, 2012, 04:24:15 PM
Hi Mark,
I did manage to get the first run with the attached tank, but it tended to draw air, and I aso think that there is a leak in it.
The fuel does draw when I choke the intake. I did install a separate tank and did elevate it, which did help initially but then it flooded so I took it back down to neutral.
NVA? May I ask what you mean?
The head is still quite red, so I dont think it has had too much heat.

This sounds like a fuel feed problem.  Check your needle valve and back plate for leaks, use the freshest fuel you can find, and keep plugging at it.


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on March 02, 2012, 08:36:21 PM
Thanks for all the help, Fellas,
I think you have hit the nail on the head. I checked the back plate and it appeared to be slightly loose. I also noted that the head was a little loose, so I have remedied that. I will give it a go today and see if I can get it to go. The fuel is still a bit of a problem, but I will endeavour to find that ether!!!!!
Re the gasket, would a silicon gasket be ok, or is it too thin?
Manne.


Title: Re: Heron 1cc diesel - help needed
Post by: Daithi on March 02, 2012, 09:07:51 PM
Honestly - brown paper or thin card works great. That's what we used back in the days when Keil Kraft were still making that engine  ;D


Title: Re: Heron 1cc diesel - help needed
Post by: Ian Easton on March 02, 2012, 09:56:57 PM
The original gaskets were very thin stuff - just a piece of brown paper as the other guys say would work.


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on March 02, 2012, 10:54:08 PM
Thanks Daithi, I will keep that in mind.


Title: Re: Heron 1cc diesel - help needed
Post by: Bryanair on March 15, 2012, 05:13:58 PM
I once had an ETA 15 and the evening before a competition I accidently  dropped it on the workshop floor.  Come competition day and all it would do was run on the prime.  Back in the workshop I discovered a hairline crack in the backplate.
At another competition my DC Sabre would not run other than on the prime and that turned out to be the cylinder head coming unscrewed.  Sorry if this is all a bit late in the day but as the others have said I think this is where your problem will lie. 

Bryan


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on March 18, 2012, 09:35:42 AM
Great, thanks for the info. I have added a bit of ether from a QuickStart aerosol and have had a loner run, but it will not maintain anything longer than about 30 seconds. I will make a new backplate gasket and try some more ether. 


Title: Re: Heron 1cc diesel - help needed
Post by: Ian Easton on April 08, 2012, 04:39:18 PM
How's the Heron going?


Title: Re: Heron 1cc diesel - help needed
Post by: BlueBaron on April 26, 2012, 02:31:05 PM
Can use a playing card from a deck of cards to make gaskets from.  :)


Title: Re: Heron 1cc diesel - help needed
Post by: Manne on April 27, 2012, 04:06:38 AM
Advances with getting the Heron running are on the back burner for a bit. (Life has got in the way, but I am starting to see daylight at the end of the tunnel).
I have the Heron mounted on a bench and see it as I walk into the workshop, so she cannot be forgotten.
I have a new gasket to cut and hopefully will give the old girl a spin over the weekend.
Thanks for all the replies.
Manne


Title: Re: Heron 1cc diesel - help needed
Post by: proctor on December 27, 2012, 04:40:14 PM
One check is to screw down the contrapiston hard so that it actually stops the piston from moving. Then back it off a couple of turns, turn the engine by hand and see if it moves the contrapiston and then check to see how far it actually moved (if it fails, then there isn't enough compression)

It sould be able to push it back a couple of turns on the compression screw

Just about everything has been covered so far but I have often found diesels with a stuck contrapiston.
You can screw them down but they don't always follow when you back off compression, not because of lack
of compression, just plain gummed/laquered up. The only answer is to take cylinder out and carefully drift
contapiston up the cylinder to free it up. Only do this if you know contrapiston is not following ie you back
off compression, flick with a prime in and compression screw is loose. Kind of last resort though.  John