cranking a diesel engine by hand

[Batista230]

Is it possible to star a heavy diesel engine by hand say a 2.5 DI
I knows in days gone by before the starter motor they used to start petrol engines by attaching a hand crank to the cam shaft
Someone told me that with a diesel you will not get the engine to go fast enough; is this true or not?
If it can be done where can I buy a hand crank from (the crank would have to have a centralfugal clutch inside it so as when the engine spins and runs the end with your hand on dose not spin as fast?
And where would you attach this tool to?

Thanks
batista230

 

[GregLocock]

No, you won't be able to. In order for the engine to start you have to be able to turn it over at a speed fast enough for it to run, probably 60-100 rpm or so. In order to do that you have to overcome the compression ratio of the engine, which on a diesel is rather high.

In the past it may have been possible using decompression valves, but a modern automotive engine is unlikely to be fitted with them.

Typically starter handles fitted into a crude ratchet on the crank nose, which may pose difficulties in the case of a FWD car.

Cheers

Greg Locock


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[MikeHalloran]

Hand cranking went out of style _instantly_ when a practical alternative was offered, because of a high incidence of wrist and arm trauma.

WRT to hand-starting a 2.5DI, I'd bet that you could restart one that was already warmed up, at considerable risk to limb if not life.



Mike Halloran
Pembroke Pines, FL, USA

 

[berkshire]

With de-compressors yes, without forget it.
Some boat motors have de-compresssors and the proceedure is/was to get the thing turning over as fast as possible on the hand crank, then trip the de-compressor off. If you were lucky it woulf fire off, if you were not it would slowly chuff to a standstill, and you would then start the whole proceedure again, until it fired off or you were exhausted.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[LadaTrouble]

We used to hand crank Lister engines - the crank handle was on the camshaft, so the crank ran double speed. I'm left handed, and it was a mission for me to start the singles - open the valve lifter and start cranking, get it going as fast as you can and then drop the lifter....but I had to change hands to do that. If it didn't start, it was downhill from there as I got weaker and weaker. Strangely, the twins and triples were easier to start than the singles - more flywheel weight? and being able to drop a valve one at a time.

 

[DanEE]

Fixed Base Engine?? and do you have some room around the engine?

Use a hand cranked aircraft engine inertial starter... I have one that found its way into my family junk "treasure" pile decades ago.. a Bendix Eclipse Series 6 hand crank inertial starter. The torque limiting clutch on it is set to 550 ft lbs and capable of starting aircraft engines up to 2500 cu inches per the Bendix Spec... able to store a considerable amount of human sourced energy in a small package... the whole unit is about 8 - 9" in diameter and about 8 inches long..

They were built in hand cranked and combination hand crank, equipped with a small electric motor and using a fairly small battery, to spin the flywheel up to 10-11,000 rpm. The flywheel stores enough energy which is transmitted through a 100:1 ratio stacked planetary gear set to turn the engine over...

Hand Cranked Inertia Starters

http://www.pilotfriend.com/aero_engines/aero_eng_inert.htm

http://www.youtube.com/watch?v=WkPFRpbSU9o

http://www.youtube.com/watch?NR=1&v=3zXkVQnVmuo&feature=endscreen

Electric motor version to spin flywheel up to speed...

http://www.youtube.com/watch?v=GrrTtbA8Ujs&feature=related

This is 1925 era technology (when they were first designed and built) and the Wright R975 and Pratt & Whitney Wasp Jr R985 radial engines were probably the first major large scale use of these starters...

Old technology has a way of coming back.. FIA 24 Hour Endurance racing has sanctioned use of Hybrid energy storage systems, Porsche (and I think Audi) with KERS (Kinetic Energy Recovery System) (flywheels), Toyota using electric motors and super capacitors..

 

[dgallup]

My '38 Ford Ferguson 9N has a hand crank. Even though it's only about 28 HP with 4 low compression cylinders, let me tell you I will do anything to avoid having to crank it by hand. I can't imagine hand cranking a diesel.

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[moon161]

I have a benz 240D with an 2.4 l OM616 IDI diesel, easy enough to turn over by hand w/ a 1/2" ratchet. I'd be cautious about starting anything w/o a ratchet or 1 way clutch on the crankshaft, don't know why hand cranks didn't include some mechanism to let the crankshaft overrun.I don't think this engine would kick too hard on a reluctant start, between the 15W40 and the other piston compressing behind.

That being said, it needs more speed and heat to get an ignition event than a gasser which will at least backfire for you at low revs. If the compression event is not fast enough, you will not stay far enough ahead of heat transfer and leakage to get a compression ignition. A reluctant diesel start can seem like forever when the battery is doing the work, forget a person. One winter, 08-09 the glow system was bad and I idled it at work until the air temp was >15F.

It roll starts well enough, I'd estimate 3-5 guys and/or a sufficient incline if not warmed up.

Now that I think about it, I would start it with a bicycle on a dare.

 

[berkshire]

LadaTrouble (Automotive)
That brings back memories. My dad was an electrical engineer. In the late 40's and early 50's in the UK., not all of the farms were electrified, so the farmers used Gen sets. These were usually Lister or Petter, with the majority being those Lister single cylinder twin flywheel diesels. So I would get to crank while my dad manned the de- compression lever. It was amazing the number of times we turned out at 4-00 am to " I can't get my generator to go, and i've got to get the cows milked", to find out that the farmer had simply let the unit run out of fuel, and had then not bled it properly. Then when he could not get a start, had called the " experts".
Mind you when you got it sorted, there was nothing more satifying than that first thud followed by a cloud of black smoke then the Thump -----Thump -----Thump---Thump --Thump _thump-thump thump of that engine building speed against those fywheels.
B.E.


The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[patprimmer]

A 1902 Oldsmobile had an inertia crank start. The carank got the flywheel spinning reasonably fast then either the flywheel engaged or more likely the valve train engaged and the inertia in the flywheel started it. Not exactly a new idea, BUT it was spark ignition.

The feature of cranking spark ignition is that you MUST retard the spark to ATDC it avoid a broken arm and the possibility of the engine running backwards.

Another feature of crank starting is as pulling up to TDC, if the compression makes the load to high, you simply hold against the compression for a second or two while some pressure bleeds off past the ring gaps or wherever, then flick it over TDC.

While I am sure that a diesel injection timing can be retarded,I would think that the extra complexity of that along with the extra compression and the requirement that the heat and compression be retained long enough to fire the charge would strongly mittigate against cranking a diesel.

Regards
Pat
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[hydroman247]

The ones I remember were small single cylinder diesels with decompression. The actual crank slotted into the front of the flywheel which had a loose spiral bayonet type fitting so once the flywheel speed was more than that of the hand crank, the handle would slide out of the socket to prevent arm damage.

Still, if it didn't start the first 2 times of trying, I would be knackered and probably wouldn't get it going for a while.

 

[patprimmer]

hydro
How did you ensure it did not fire before TDC

Regards
Pat
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[hydroman247]

Once the speed was over about 80rpm I flicked the decompression lever and as my focus went from cranking to leaning over to switch the lever, the flywheel would overtake my crank handle speed and disconnect it.

 

[SomptingGuy]

You have to keep cranking until the in-cylinder temperatures rise enough to allow combustion. That could take minutes, but it will eventually get there. I remember well the cold-start tests of IDI diesels in my student days. 60s of cranking, loads of smoke and then finally the engine would pull its own weight.

- Steve

 

[Compositepro]

I believe most instances of broken bones occur due to an engine firing before top dead center and the crank getting pushed in reverse. I guess that a ratchet mechanism on the crankshaft could prevent injury.

 

[moon161]

Pat,

I don't think ignition BTDC is a problem w/ diesels when starting.
1. The fuel charge is introduced over a fairly long interval. On mercedes 61x diesels, I think the fuel injection occurs from 23* BTDC to 15 after. So the 'bang' at autoignition temp is not a big one, unless ether or WD40 is misted in.
2. The early ignitions seem partial anyways. The bump you hear and feel from the partials is distinctively different than the first 'clack!' that throws it over and gets you going. The 61x prechamber includes the glow plug, and also a metal ball suspended in the path of the injector jet. The glow plug and the ball I think respectively give and sustain heat in the chamber that promotes a pilot ignition event.

 

[zzonbi]

Yes, it is possible. With the engine on car use the leg crank: give the car a push, then jump in and clutch 2nd gear.

 

[moon161]

>>Yes, it is possible. With the engine on car use the leg crank: give the car a push, then jump in and clutch 2nd gear.<<
My choice in a pinch. Needs a bit more speed than a gasser tho.

 

[LadaTrouble]

They don't kick back on ignition, but from compression - it's like hitting a brick wall. You have to use a decrompressor, and have to get it spinning fast enough for the flywheel to take it over compression. Forget all you know about hand cranking a spark ignition engine, you will never get one to turn over and start with just one turn of the crank handle.

I learned to kick start old British singles in my youth - it's all technique. I was thinking of putting a Lister single into one of my BSA's, but there is no way you could start one with a kickstarter. A motorcycle kickstarter is geared down, the Lister is geared up with the crank handle on the camshaft.

 

[BigClive]

Many years ago I often had to hand-crank a generator powered by a three-cylinder Lister. It always started quite easily - but this was in the northern tropics of Oz - so the ambient temperature was always very hot.

I think the Lister was in the 2 to 2.5 litre capacity range. But it had a decompressor and (I suspect) a very heavy flywheel - so you could really build up quite a lot of momentum before disengaging the decompressor.