Starting Diesel Engines

I made trouble for myself a while ago. Everything is back on the shelf for now though. My efforts were mixed. I plan to try again.

https://www.coxengineforum.com/t3892-i-might-be-making-trouble-for-my-self-with-a-diesel?highlight=diesel+trouble

Phil

Thanks for that Roddie, I'm not sure how old the fuel is. Inherited with engines, but I did have it under suspicion. I'll buy some fresh stuff.

Cheers

Diesels require a much faster flick than glow engines.  A slow flick gives time for the heat of compression to escape into the head, piston, and cylinder. Few can start them with finger touching prop before flick. Works better to takes short swing at it.

Next thing that causes beginner problems is flooding. Start out with no fuel in tank. Find the compression setting that will fire and run out a prime. Then fuel the tank and open needle 1/4 turn at a time only after it fires on the prime and dies.

My diesel starting tips - and I have started alot of diesel engines! I am a diesel fanatic!

Do not have any part of the fuel tank above the level of the NVA

If all the settings are astray (which they probably are!) - turn off the fuel and do a compression only firing by:-

Prime the engine through the exhaust port against the piston wall,
with the piston towards TDC (not on top of the piston!).

Back off the compression and turn the engine over slowly by hand just to check you haven't got too much fuel in
and are locking.

Then start flicking the prop sharply with intent and gradually advancing the compression untill the engine fires and runs a
short burst.
If you take too long over this all the fuel may be gone and you may just get to a high compression position, without it firing, in
which case start again.

Once you get it firing consistently and running a short burst. Hook up the tank, fill and choke the fuel up to but not into the carb. When fuel reaches NVA, ONE, AT MOST TWO more turns of prop to prime (finger over choke! Be careful!).

You are now ready to actually start the engine, and it will normally be achieved with two or three correctly and smartly executed flicks (with intent!). If engine fails to start, but flicks over easily, screw in compression screw 1/8 turn at a time, until engine fires. If no result and engine very hard to flick over, re-prime .

If fuel is obviously present e.g. wet exhaust output, and engine does not respond, it is flooded. Keep on as much compression (screwed in) as will allow flicking over. Flick/Adjust compression up/down as necessary until engine fires. Make sure fuel level in tank is not above NVA. When started, close needle to 1.5 turns approximately, and unscrew compression to achieve maximum power. Generally, needle will need to be closed to increase speed but sometimes doesn't make much difference.

If labouring results, unscrew compression.

If misfiring results, screw in compression.

HOT RE-STARTS
From the last best hot running setting (max. speed under load) it will be found necessary to UNSCREW the compression lever 1/4 turn . Not always necessary if you have a good flick!

COLD START = HOT RUNNING SETTING PLUS 1/4 TO 3/4 TURN IN OF COMP. SCREW.

My diesel advice, and my whole previous modelling life (60s,70s,80s) was spent wholly with diesels, glowplug was considered something you only used for full-house c/l stunt.

First rule of diesel, bigger diesels, that is .09 upwards, are FAR easier to start than little ones, .049 and smaller are generally PIGS to start!

Follow the advice given above in previous answers to the letter and you should have no problems, BUT, beware of the dreaded hydraulic lock, this is caused by too much fuel and too much compression, you can damage the con-rods or crankpins of small engines, and with larger ones you can damage yourself, when your finger slides along a sharp-edged prop! (painful!)

Starting diesels is an acquired knack, practice makes perfect as with anything, and I would seriously advise that you start with a larger (.15-ish) engine if you have one, a good .15 should start within a flick or two once compression/needle settings are correct.
Obviously, all of the above, and everything in previous answers assumes that the engine is in good condition, a worn diesel engine can become difficult or impossible to start.

Good luck!

Wilf

ebeneezer wrote:Thanks for that Roddie, I'm not sure how old the fuel is. Inherited with engines, but I did have it under suspicion. I'll buy some fresh stuff.

Cheers

Hey ebeneezer, Looks like you got some great advice on starting techniques! That's great! I read through them and learned a lot myself!

I also read "Bernie's" (Cox International) thread on new product suggestions; where there was an inquiry on diesel fuel. Bernie suggested "Davis Diesel"... UNFORTUNATELY; they only ship "fuel" via "ground" in USA ONLY... but; will furnish you with a formula to "blend your own" with components that should be generally available; there in England. In fact; probably easier to obtain the components for diesel model fuel, than glow fuel. The mono-nitromethane in glow fuel (desirable for running our "little screamers"...) is something you have to "hunt" for... and you're better off trying to find that component "locally"; so as to avoid "hazardous shipping" costs.   The methanol and castor oil are easier to obtain.

At least "Davis Diesel" states they will give you a blend-formula and it's components... and you can eliminate a variable in getting your new-found mills' "hearts beating"... Best of luck!

http://www.davisdieseldevelopment.com/price_list.html

Hey ebeneezer, Do you have any Cox .049 engines? I mentioned "Bernie"; (Cox International) in my last reply. On his "Performance Parts" page; he offers a "hardened" replacement crankshaft for these engines... ("Killer Crank") A regular "stk." crank tends to break at the "pin" w/diesel use. The "Killer Crank" is hardened... and is more durable.

What's more; he also offers the "top end"... (head conversion and replacement discs)

As I said previously; I don't know much about diesels... and I'm not sure if the Cox conversions are more suited to the TD (rotary) or reed; induction style. Bernie could tell you more.

Roger

ebeneezer wrote:Hi guys. I've just inherited a load of small vintage diesel engines. I have tried running an AMCO 2.5 by its size with no joy. As the only engines I've ever played with are glow engines I know nothing about starting diesels. Where do I start? Is there a book I could buy or a vintage engine forum I could get soime help from?

Cheers  

For a book I would highly recommend "Dr. Diesel's Diary" from Eric Clutton (Dr. Diesel).

You can get a wealth of information for care and feeding of diesels at:
   http://www3.telus.net/dieselcombat/diesel_care.htm
It is a Canadian group that flies diesel combat.

You can also get diesels, fuel, and information from Ed Carlson of "Carlson's Engine Imports". Best to call him. He used to stock diesel fuel in quarts, but it's been quite a while since I have bought any. Not sure if he will export.

If your diesels have been run already, chances are the compression is already set to run...unless you or someone else has been "tweeking" the compression screw.  A safe place to start in that case is to put the piston at TDC then screw the contra piston down until it just touches the piston...then turn the compression leaver one full turn out. That should put you in the ballpark.

I would suggest purchasing new fuel. That would eliminate one obstacle. You might also look around for someone who already knows about running diesels. Learning is much faster if you have a teacher.

Good luck whichever way you go.

George

Edit: I searched PAW diesel engines (made in England) and under ready mixed fuel they had"
We recommend Model Technic's D1000, D2000 or D3000.
Available from:
Model Technics
Vanguard Way
Shoeburyness
Essex SS3 9QY
UK
Tel +44 (0)1702 292244, Fax +44 (0)1702 298744

I agree with Wilf on this and he was quite right in pointing out the perils of flooding the engine and causing a hydraulic lock.

However, I have to modify his response as I have run diesels right down to 0.05 cc. Once you are at 0.8cc, I would always recommend increasing the ether content - right up to 50%. This makes starting much much easier on the smaller engines. There may be a downside in the power the fuel provides - it mostly comes from the paraffin (kerosene) but they will run nicely.

A poor starting diesel leads to frustration and impatience followed by a ............... busted engine.

Do not use an electric starter on a diesel engine!. Even one that you are confident that it is well set up. If it doesn't start or fire within a few flicks - something is wrong! An electric starter will not help and is likely to bust the engine. Then again, some of us do it and get away with it but I still wouldn't recommend it. (Do as I say not as I do!)

The hydraulic lock, with experience, can be used to advantage. Now, again, do not do this until you are very, very familiar with your diesel engine. The diesel engine must be a sturdy one and at least 2.5 cc (.15 ci).

When team racing or combat flying, the "pit stop" required a fast turn around. One of the tricks was a quick fill up, followed by a delicate prime (quick squirt!) into the cylinder - piston top exposed. The cylinder was hot at this stage. Then a smart two finger flick - well not a flick, more of a gentle wallop (smart tap!) - in reverse to bounce the piston off compression. Not hard enough to rotate through compression. This invariably caused the engine to fire and start running in the right direction. It took practise!

Thanks to all who responded and have given me advice, I've certainly learned a lot about diesel enginesl. I have bought some fresh diesel fuel Model Technics D2000. I have also selected a new looking DC Sabre 1.5cc and will try again excited. I will let you how I get on.

Cheers

ebeneezer wrote:Thanks to all who responded and have given me advice, I've certainly learned a lot about diesel enginesl. I have bought some fresh diesel fuel Model Technics D2000. I have also selected a new looking DC Sabre 1.5cc and will try again excited. I will let you how I get on.

Cheers

You should have no trouble with a decent Sabre, it was designed as a total beginner's engine, and even came with a spring and cam starter in it's later days, this may, or may not, still be on your engine, but either way it's a good engine to learn diesel handling with.

Just a further, personal, note on smaller diesels, the first engine I ever owned, a present for a birthday longer ago than I like to remember, was a frog 50, .5cc (Don't know what that is in CIs) and that engine almost put me off model aircraft for life! as a rank beginner I never, ever, got it to start. I finally traded it for an ED Hunter in 3.5cc (19) which was huge, heavy, and totally unsuited to a beginner, BUT, it started almost the first time I tried, and that led to something like 60 years of model building and flying!
Bigger is easier, 1/2 a turn out on a tiny diesel's comp or n/v will prevent it from running, a bigger engine won't even notice!

Wilf

Quoting Wolf; "Bigger is easier, 1/2 a turn out on a tiny diesel's comp or n/v will prevent it from running, a bigger engine won't even notice!"

I wonder if a "super-fine pitch" thread on smaller engine's comp. screw would help this condition? K.K. used to offer a fine pitch needle.

Roger

Just got my Sabre running, it was great. I have to say with one sore finger, i'm hoping it should easier now. I don't know if it was an illusian but it it seem better when I struck the prop rather than flicked it. I definately need to polish the sharp edge off the prop. Is a chicken stick any use, or a just a good glove.

Thanks for all your help.  

ebeneezer wrote:Just got my Sabre running, it was great. I have to say with one sore finger, i'm hoping it should easier now. I don't know if it was an illusian but it it seem better when I struck the prop rather than flicked it. I definately need to polish the sharp edge off the prop. Is a chicken stick any use, or a just a good glove.

Thanks for all your help.  

Well done, that man!

Yes, hitting the prop works, but as you have discovered, it's a little hard on the finger! As you start more engines you will learn the technique of the sharp flick, which will give the same result, but for now, keep hitting it, but wear a rubber finger-guard or use a chicken stick to protect your dainty digits!
I always sand the sharp edge off props, too many cut fingers soaked in diesel fuel (Ouch!) in the past, just be careful not to remove too much material and unbalance the prop, a quick rub along each edge with fine sandpaper will take the "flash" off the moulding, which is what makes them sharp.
Keep up the good work, diesels must never die!

Wilf

Thanks Wilf, I've plenty to play with. I think I might try one of the Oliver Tigers next, They aiso haven't been run for over 30 years is there anything to watch out for, how should I proceed? Would it be worth soaking them in my old diesel first.
Cheers, Mike

ebeneezer wrote:Thanks Wilf, I've plenty to play with. I think I might try one of the Oliver Tigers next, They aiso haven't been run for over 30 years is there anything to watch out for, how should I proceed? Would it be worth soaking them in my old diesel first.
Cheers, Mike

Oliver Tiger, well you are talking REAL engines now! If they are free and turn over easily, a soak in fuel won't hurt. Any Oliver should start first or second flick if the controls are anywhere close to correct, just bear in mind though that we are now talking racing engines, not DC Sabres! Be prepared to get your finger out of the way pretty fast! If the Olivers were put away with the needles set from the last time they were run I would leave that alone, just blow through the needle valve with a piece of fuel tubing to make sue it's not blocked,  just alter the compression screw to get it going, back the compression off about 1/2 a turn, prime through the exhaust port, turn the prop over slowly to make sure it's not flooded, then flick the prop (or hit it) smartly and I would be VERY surprised if the engine doesn't at least fire if not keep running. The correct prop for an Oliver for c/l flying is an 8" x 6", but for first starting I'd advise 9" diameter to slow the engine a little.
As you get experience you can feel if a diesel is about to start, the trick is to keep your left hand (if you are right handed) holding the compression screw while flicking the prop with your right, adjusting the compression up or down as you flick, (you learn which way to go from experience and the "feel" of the engine) then when it catches increase compression until it runs smoothly.  Once you have the needle valve set correctly you should never need to alter it again, just use the compression screw when starting.
Both my old Olivers back in the day would always start first flick, hot or cold.

Wilf

Thanks for all that Wilf. I'll let you know how I get on.

Cheers Mike

WOW what an engine, I just ran my Oliver Tiger . It ran fantastic it was so smooth, I think I'm in love. What suprised me was, I didn't think it was as loud  as my Cox Olympic. Now to build a peacemaker to put it in. Or do you have any better ideas? Bare in mind I could fly my electric peacemaker, but crashed it the first time I ever tried a loop  think I must  have neutralised the controls as it came over the top thus it dived verticaly into the ground.

Cheers Mike  

Just ran my TD 010, Sorry Olie. Small is still more beautiful, Thankyou Cox.

Cheers  

roddie wrote:Quoting Wolf; "Bigger is easier, 1/2 a turn out on a tiny diesel's comp or n/v will prevent it from running, a bigger engine won't even notice!"

I wonder if a "super-fine pitch" thread on smaller engine's comp. screw would help this condition? K.K. used to offer a fine pitch needle.

Roger

If you pinned the contra piston from rotating, then you could use a differential screw. Say 1/4-28 in the head and 6-32 in the contra piston, effective pitch of 224 tpi with strength of 32 tpi.