My OS55HZ has too much compression Dynatron wont turn it over

[discoferret]

Before I replaced the crankcase and pistion ring my Dynatron started it with no problem but now It wont turn it over. There seams to be alot of compression now. Is not hydro locked as Ive alraedy checked. At the moment my starter is running on a 4's lipo do you think I should get a 6's lipo for it will that have enough power to turn it over?

[Gate88]

Are you sure you put it together right? Does it turn over without the glow plug in?

[discoferret]

Are you sure you put it together right? Does it turn over without the glow plug in?

Yes easily.

[johnsandywhite]

My son had the same problem with his YS56. You say it is NOT Hydraulic locked? My son used oil on the parts when he rebuilt his and it was enough to stop if from turning over. Plug out, spin it over and bobs your uncle. It worked for him anyway.

[Gate88]

Yes easily.

Then it's hydro locked. You shouldnt have a problem turning it over with a 4 cell on a Dynatron, nearly everyone at my club starts their 55's with 3s Align starters.
As the chap above says its probably just a bit of oil left over from the rebuild. Spin it over without the plug in for 30 seconds, replace the plug then without lighting the plug tip the heli over at 90 degrees, exhaust side down, and turn it over a couple of times by hand. This should let any residue out into the muffler, then with the heli still on its side spin it over with the starter until you can get at least 5 second bursts out of it. After that try it back on its skids and go for a start.

[discoferret]

Then it's hydro locked. You shouldnt have a problem turning it over with a 4 cell on a Dynatron, nearly everyone at my club starts their 55's with 3s Align starters.
As the chap above says its probably just a bit of oil left over from the rebuild. Spin it over without the plug in for 30 seconds, replace the plug then without lighting the plug tip the heli over at 90 degrees, exhaust side down, and turn it over a couple of times by hand. This should let any residue out into the muffler, then with the heli still on its side spin it over with the starter until you can get at least 5 second bursts out of it. After that try it back on its skids and go for a start.

Ive tried what you suggested and it still doesnt turn it over. It feels like the dynatron hasnt enough torque/power to turn it over.

[robgt]

Is the head shimmed correctly?
I can't believe a dynatrom can't start an OS55. Is the battery flat?
LOL
Cheers,
Rob

[Gate88]

Is the head shimmed correctly?
I can't believe a dynatrom can't start an OS55. Is the battery flat?
LOL

That's all it can be now, if you're sure theres a shim under the head then it sounds like a starter issue. Have you tried another starter?

[rachel]

Humm just my observation but the dynatron is really best at over 18 volts .
I have seen the dynatron on 4S be outperformed buy an align super starter many times .

If however it is flooding (hydraulicing) turn the heli on its exhaust side (right over with the rotorhead vertical ) with the tail boom lower than the nose and wind it over at full throttle with the fuel off and NO GLOW !!!!!!!!!!!!!!!!!!!!!!

once it spins freely plonk it back on its skids and start as normal.
If it wont spin still remove the glowplug and spin the engine over .

Just a question, is there any chance you have put the piston in backwards ??? if you have it will distort the piston skirt and cause the jam.

hope this helps.
Rachel

Ive tried what you suggested and it still doesnt turn it over. It feels like the dynatron hasnt enough torque/power to turn it over.

[discoferret]

Is the head shimmed correctly?
I can't believe a dynatrom can't start an OS55. Is the battery flat?
LOL
Cheers,
Rob

Yes and the battery is fully charged. It was working fine last week. I 've replaced the crankcase and psiton ring and have just had the engine out to check if I put the piston in correctly which I have.

That's all it can be now, if you're sure theres a shim under the head then it sounds like a starter issue. Have you tried another starter?

I havent got another starter but I tested it out with my 24v cordless drill and it easily turns it over.

Humm just my observation but the dynatron is really best at over 18 volts .
I have seen the dynatron on 4S be outperformed buy an align super starter many times .

If however it is flooding (hydraulicing) turn the heli on its exhaust side (right over with the rotorhead vertical ) with the tail boom lower than the nose and wind it over at full throttle with the fuel off and NO GLOW !!!!!!!!!!!!!!!!!!!!!!

once it spins freely plonk it back on its skids and start as normal.
If it wont spin still remove the glowplug and spin the engine over .

Just a question, is there any chance you have put the piston in backwards ??? if you have it will distort the piston skirt and cause the jam.

hope this helps.
Rachel

Ive just had the engine out and checked that I put the piston in correctly which I have. Since I replaced the crankcase and piston ring it has alot more compression than before. Perhaps a 4's lipo just isnt enough to turn it over.

[Gate88]

Perhaps a 4's lipo just isnt enough to turn it over.

If that was the case then you'll have a rip snorting engine when you do get it going!!!

[rachel]

There is a very popular adaptor that used a Makita 18V battery that will help as I think 4S is a little low on power for you.

My align starts my OS55 and mr os 91S no problem bar the horendous vibration lol
watch this its a richie and mattie clasic !!!!!!!!!!!
Align vs Dynatron Starter - YouTube

Rachel

[Nick B]

4s dyna should be turning a 55 no problem!

[Tony15]

4s dyna should be turning a 55 no problem!

+1
test your 4s with a multimeter incase one cell has failed a 4s dyna will start a new (unrun) 91 in the winter.

[robgt]

Perhaps a 4's lipo just isnt enough to turn it over

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

Cheers,
Rob