My OS55HZ has too much compression Dynatron wont turn it over

[Tim Procter]

Sounds like a duff lipo on the dynatron to me.

[rapidgaz]

I can start my Aurora (OS 91HZ-R 3D Speed) with my Dynatron on a 3S pack.

Cheers,
Rob

I have started my srs on 3s also rob before with dynatron.


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[electricsceadu]

i start my os91's with a dynatron from a 9 1/2 year old 12v car battery and its never failed yet (even in the winter), its also started a 75cc plank that would start by hand
so 4s on a 55 the start will be taking it easy

reset the needle to the std settings
take the plug out
set the throttle full open with the fuel turned on
spin the engine over and pump fresh fuel through the engine
turn the fuel off and spin it over again
refit the glow plug (double check it works, including the glow stick/2in1)
tip the heli over to the exhaust side and go for a start
once the engine coughs and splutters turn the fuel back on
it should be running

[chris jones2.4]

Yes and the battery is fully charged. It was working fine last week.

usually things are before they break sorry i had to do it

[soggybongo]

i start my os91's with a dynatron from a 9 1/2 year old 12v car battery and its never failed yet (even in the winter), its also started a 75cc plank that would start by hand
so 4s on a 55 the start will be taking it easy

reset the needle to the std settings
take the plug out
set the throttle full open with the fuel turned on
spin the engine over and pump fresh fuel through the engine
turn the fuel off and spin it over again
refit the glow plug (double check it works, including the glow stick/2in1)
tip the heli over to the exhaust side and go for a start
once the engine coughs and splutters turn the fuel back on
it should be running

in my humble opinion bearing in mind i aint no electrician and only a mechanic i would say either something is binding i.e a bearing put under too much pressure when the compression increases due to the glowplug being inserted or your battery charger/ conditioner is giving of a duff reading or your starter is at fault. If you can turn the engine over with a battery powered 24v drill and the engine runs ok this shows there is nothing wrong internally with the engine.
Have you had the engine runnng after the overhaul?

[soggybongo]

Just had a brain wave, have you tried to heat up your engine with an air dryer on full heat prior to starting? (the whole engine block and not just one side). I know this helps with new engines to reduce the pinch. My last though is to add an extra shim to the head but if it ran good prior to the overhaul i doubt you would need this.

[electricsceadu]

as he say's it turns over fine with no glow plug we can only assume that the engine is ok
its either a hydro lock or a problem with the starter
a glow engine built with normal oil will hydro lock for a good while until the oil has been pumped out of it

[del19_82]

I would maybe back the plug off a wee bit, fire the Heli up and then tighten the plug up again. Have seen this done a few times and have had to do it on occasion with my hyper when it's being stubborn lol


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[soggybongo]

as he say's it turns over fine with no glow plug we can only assume that the engine is ok
its either a hydro lock or a problem with the starter
a glow engine built with normal oil will hydro lock for a good while until the oil has been pumped out of it

sorry mate when I said turn over the engine with a 24v battery drill i meant with the glow plug in and engine starts also runs ok. If the engine starts with this combination then the fault is with either the batteries or starter. If he had low compression prior to the overhaul then weaker batteries or starter probably would not show signs of deterioration.

[del19_82]

sorry mate when I said turn over the engine with a 24v battery drill i meant with the glow plug in and engine starts also runs ok. If the engine starts with this combination then the fault is with either the batteries or starter. If he had low compression prior to the overhaul then weaker batteries or starter probably would not show signs of deterioration.

The problem with doing that with a plug in is if it's a hydrolock as thought then your running the risk of wrecking the engines internals.


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[soggybongo]

ok why not if you have it mate on your drill, use the ratchet (don't know the word for it) so you dont round off the screw head (as if you were screwing cross head crew into a piece of wood). Are you using a different length glowplug , is the brass washer under the glowplug?
Just trying to help!

[del19_82]

It's not so much the start shaft you will damage but the con rod can snap if there is too much torque on it from a hydrolock . I think (but may be wrong) that all glow plugs are the same length.


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[soggybongo]

If the cylinder fills with liquid while the engine is turned off, the engine will refuse to turn when a starting cycle is attempted. Since the starter mechanism's torque is normally much lower than the engine's operating torque and momentum this will usually not damage the engine but may burn out the starter. The engine can be drained as above and restarted.

Just one last thought, have you had the backplate off? (if you have, have you installed this upside down)?

If you take off your bakplate you will see a recess or flat bit that goes towards the piston, this is to ensure your piston does not hit the backplate when at bdc (botom dead center)!
the flat bit needs to be at the top.

[sacko]

Can you turn the engine over by hand with the plug in, using the starter wand?

[electricsceadu]

If the cylinder fills with liquid while the engine is turned off, the engine will refuse to turn when a starting cycle is attempted. Since the starter mechanism's torque is normally much lower than the engine's operating torque and momentum this will usually not damage the engine but may burn out the starter. The engine can be drained as above and restarted.

Just one last thought, have you had the backplate off? (if you have, have you installed this upside down)?

If you take off your bakplate you will see a recess or flat bit that goes towards the piston, this is to ensure your piston does not hit the backplate when at bdc (botom dead center)!
the flat bit needs to be at the top.

with a high torque starter with the engine totaly flooded the liquid cannot compress the weakest link will fail
if the rings shot it will pass the ring
if the engines good it can and will bend the con-rod