582 idle vibrations - Cosmos trike installation

[Guest rocketman]

I have a 582 mounted in a Cosmos trike. We recently renewed the water pump seals which meant removing the rotary vavle timing plate. First runs went great and got a few flights back in, then the springs went in the clutch. Replaced them. Next flight blew the clutch completely on T/O. This time replaced the clutch pads After rebuilding the gear box, I now find that there is sharp vibration at idle (it's pretty dramatic to see the engine bouncing around) but this disappears at about 3000 rpm and by 4000 rpm, the engine is smooth. I'm trying to sort out whether the vibration is due to the clutch slipping at idle rpms, or have we got the rotary vavle timing wrong (too far advanced). We only had a screwdriver to determine TDC of the piston for timing. We haven't done any more test flights yet to see how the engine performs in flight.For non Cosmos readers, Cosmos threw out the original clutch assembly and inserted their own. Cosmos have since gone bankrupt and theres no spares around. We've determined that we can re-manufacture most of the clutch parts. We're up in Malaysia so we don't have a lot of access to spares here and I don't want to go down the road of a new gearbox yet. Anyone got any clues?Neale.

 

 

[Yenn]

If you got a few good runs in as you say, surely that would make you think the rotary valve was OK. Did you use the screwdriver to find the highest point of the stroke, or to find two positions equally below the top, but on each side and then mark TDC as centrally between them?

 

 

[Guest rocketman]

Basically, we kept cycling the the crankshaft at the TDC position until we "felt" that we were at TDC (smaller and smaller bites of the cherry, so to speak). It's only in hindsight that I've wondered whether I should have turned the crankshaft in the normal direction of rotation to eliminate any backlash in the cross-shaft as we approached the final TDC spot. I'm just wondering if the rotary timing plate is 1 notch towrds advanced now and what the result would be. At idle, would it give a form of backfiring? Surprisingly enough, the engine seemed to deliver more power on T/O before the clutch went west. As an aside, we had to replace the water pump seals (which is why the timing plate came off), the stator (RPM gauge indications incorrect - sat around 2000 rpm at all times) (I think that the stator was actually serviceable, and the problem was a bad connection in the wirng harness under the seat)(fixed that, then the indications died completely)(changed the stator output to one of the lighting coils and it's been sweet ever since). Been on a fast learning curve with these engines. Neale.

 

 

[Steve L]

heres a site that has videos on overhauling the 582 especially the ignition, it may offer some tips

 

http://www.lightsportaircraft.ca/rotax582rebuildingdvd/

 

hope this helps

 

steve

 

 

[Knighty]

rotary valve plate

 

Just going off memory, the rotary place can be rotated 180 degrees to get the timing closer to the mark, have you tried this??? I am thinking that you may have accidently spun the plate around as this is easy to do when you're busy worrying about the bigger picture.

 

Cheers

 

Knighty

 

 

[bilby54]

Hi Rocketman,

 

I have operated 582's for several years on a Drifter and your symptoms makes me think that it is possibly not the engine at all.

 

I had to wear the expense of a new engine when the Rotax agent could not find the problem with the vibration in the engine. The note in the logbook says that the bearings in the gearbox were replaced as part of the overhaul. To make a long story a bit shorter, the real problem was with the gearbox and overhauling it did not solve the problem.

 

The vibrations can cause some very dramatic effects and finding the cause can be a real challenge but I would not be convinced that the rotary valve is at fault.

 

Cheers .... Bill

 

 

[Guest rocketman]

Bilbly, You're right about the rats! We have a plauge of rats from the oil palm plantation the other side of the strip checking us out. Only problem is that they are attracting the snakes as well.Regards the 582. Tried turning over the timing plate when we we're looking for an optimium positon when setting up the timing. The engine actually seemed more responsive after rebuilding it. My 582 x-spurt is now thinking that we may have dropped a spacer off one of the gear shafts. (I don't think we did). And I can't find any reference to a floating spacer in any of the parts catalogues. We might pull the gearbox apart again tomorrow for a squizz. N.

 

 

[Guest rocketman]

Update on the vibration saga. We stripped the gearbox again (and did one of the other engines we have lying around). The clutch pads look as though they are chattering on initial engagement, (black streaks on one of the pads and some wear marks on the other), so it looks as though the clutch just needs bedding in. The other engine we stripped to inspect it's gearbox didn't have a spacer on either shaft. Will post more updates after we do some more runs.Neale.

 

 

[Guest rocketman]

The vibration at idle is definitely due to the clutch not fully engaging - chattering. Clutch pad dust in the vent holes. We stripped another gearbox and installed the damper in lieu of the Cosmos clutch. Different noises now. And the starter has to work a lot harder too. What to do, lah? At least we're flying again! If we went down the road of manufacturing our own pads again, I'd make them a bit thinner, or up the tension on the drum springs.Now to look at the engine mounts. Neale.