Grey Vs Blue

[Lorax 0]

Question to the group...I have the option to purchase cheaply an unused never started grey head.  What are the things to consider as opposed to buying a new blue head..

Obviously the grey would need a full strip and rebuild with new seals. But would the blue be a better option. Better crank? Ceramic seals?

 

[Dusty 126]

Contact an experienced rotax repair shop and get an estimate for a rebuild and go from there. I personally have no preference for blue over silver  as the later silver tops had the same crank as the blue ,the waterpump seals don't give trouble if using dexcool. These seals can be retrofitted with ceramic seal if you feel the need. The bluetop cooling is better able to tolerate poor throttle handling.

Cheers

Dusty

Edited 2 Oct 2021 by Dusty

[ChrisBolkan 130]

Probably going to get hammered for saying this, but if you have a chance to get an unused grey head for a good deal grab it! Assuming it has been kept inside and not left out in the weather, I would replace the carb boots and any external rubber and put it on the plane and run it. Break it in properly on the ground (just in case). Normally I have done the break in procedure in the air over the airstrip I fly out of (just in case) because it is much easier to perform in the air than on the ground. But you don't know anything about the engine. 

Make absolutely sure since it is a grey head with rubber seals that you either buy pre-mix dexcool or mix up your own with DISTILLED water and those rubber seals will never give you a problem. If the engine runs and works great as-is, fly it and gain confidence until you trust it and then fly the shit out of it. When you decide it is time for an overhaul send it to lockwood or another reputable shop and have them put a ceramic seal in place of the rubber if you want. 

You might want to get a couple of the carb "short kits" or whatever they are called (the rebuild kits that only contain gaskets) and if the carbs give you any problem during startup and break in, rebuild the carbs.

Make sure you plumb the oil reservoir in properly, fill it with oil properly using the bleed screw, and watch for any drop in oil as you break in and run the engine for the first several hours. If all is good you should be money!

Like I said I may get hammered for saying this but I see no reason to do a time only rebuild of one of these engines if it is "new" and been kept in decent indoor conditions since purchased.

[Lorax 0]

Sage advice. Thank you for taking the time to type up a informative reply.

 

[1avidflyer 1983]

Couple of years ago, I picked up a Kitfox 3 project that had never been finished.  It had a never run 582 gray head with it.  I have a shop nearby me where I have taken probably at least a dozen two stroke engines to over the years, they have a good mechanic.  He pulled the engine apart, and didn't find anything wrong except for this.  When the engines are assembled in the factory, they use an assembly grease to protect against corrosion and initial lubrication on start up.  That grease was close to 30 years old, and was all dried out.  He washed it all out and the bearings were fine but he figured there would have been problems if I had just run the engine without the teardown.  Of course new seals were installed on the reassembly.  That engine had a C gearbox, and I took that off myself.  The front bearing didn't run smooth, and I figured it was maybe corroded.  I sent the gearbox off to Steve Beaty at Airscrew performance to change out the front bearing and it was the same as the engine.  No problem with the bearing, but the assembly grease was all dry and caused the bearing to appear to be bad.  That is my experience with a never run rotax that was 30 years old.  Make what you will of it. :-)   JImChuk

[Lorax 0]

Thanks Jim. Never would have thunk of that. I'll be stripping it before running.

[ChrisBolkan 130]

I will acquiesce to Jim's experience with a new old "in the box) engine. My experience has always been with engines that have at least been previously run....but some not run for WELL over 10 years. I have always used the approach I described above and had great results. But those engines had been run previously, so any grease applied during assembly would have been diluted and gone. My experience is first hand including performing all disassembly, inspection, overhaul and re assembly activities myself (with the exception boring cylinders). 

I have seen first had with my own eyes what the 582 looks like inside at all phases of time in use many times. If it had been previously run I would still recommend what I suggested above, but in light of discovering dried grease in an un-run engine, it is probably best to disassemble it first and clean up the dried grease.

Thanks for not letting me steer him in the wrong direction Jim.

[nlappos 413]

Great source of gaskets and o rings:   http://jbmindustries.com/GASKETS.html