Sport Pilot Talk

shasta · Joined: 06 Sep 2011 Posts: 23 Location: sacramento

Here is a question maybe some of you Rotax mechanics can answer, as I seem to be getting many different answers reading online. I was wondering about what it would cost to overhaul a 912ul or a 912uls. I know this can vary greatly but I was curious about what to expect for a major.

I know most of the 912's are a long ways away from needing it but I have seen a couple of airplanes that are getting close and one very nice one that was at 1600 hours. I am just trying to get an idea about what I should be setting aside for an engine fund if I decide to purchase something with a 912 in it.

Thanks

roger lee · Posted: Mon Oct 10, 2011 9:23 am Post subject: 912 rebuild cost

The cost to do an overhaul on a 912 is approximately $12K and that needs to be done at a distributor that has someone qualified to tear it down to the case. I recommend to all my clients when it's close to sell their engine to an experimental owner for $8-$10 and then just buy a new one. The experimental folks aren't required to do a rebuild. (They should anyway, but) The cost is the same, but you end up with a zero time engine. The rebuilt one will never be a zero time engine again, but should last well into the 4K hr. time frame and more. Flight schools get to their TBO's much quicker than the private owner and that is a good way to keep engines rotated.

drseti · Joined: 28 Nov 2009 Posts: 1390 Location: Lock Haven PA

I agree with Roger. My engine is at 1045 Hobbs. When I get to 1900 I'll order a factory-new one, in the crate, for something like $20k (and am setting aside $10 per flight hour in my TBO Fund). At 2000 hrs, I'll swap the engines, and then advertise the old one on eBay Motors. I'll probably get $8k or so for it, assuming it's still running strong, so will be no worse off financially than if I had done a rebuild.

Brian Carpenter (Rainbow Aviation) takes this one step further. He recommends swapping out for a new engine at midtime. That way, you're staying outside of the up-slope in the maintenance curve. I guess you could get more for a 1000 hour engine than you could for a 2000 hour one, but this approach will probably end up costing you more. OTOH, if it keeps you from ever entering the wearout phase, your chances of an inflight engine failure are probably reduced.

shasta · Joined: 06 Sep 2011 Posts: 23 Location: sacramento

Thanks for the information. I guess that is pretty much what I feared it was going to be. I was visiting a guy who is building a kitfox and that was pretty much the advice he was given also. When the engine was about done just pull it out and sell it.

I just was wondering as I saw an ad on Barnstormers for a guy who would do rebuilds on 912-914's for $1800 plus parts. Also another ad, a few weeks ago, was giving a 6k rebuild credit for a 912uls that had 1600 hours on it. It was an AB Kitfox Vixen. He did say it did not need it but he would lower the price to cover the cost of an overhaul. I was just hoping it would only be about 6k but I had heard the 10-12k figure before too.

Anyway thanks for your time. I am just trying to get as much information as I can before I make any decisions. Nice to have a forum like this to ask questions.

Jim Stewart · Joined: 12 Oct 2006 Posts: 259

Back when I bought my CTSW it didn't take me long to figure out that selling a 3/4 run out 912 would be a better deal than rebuilding it. Now I suspect there will be a glut of run out engines on the market when it's time.

drseti · Joined: 28 Nov 2009 Posts: 1390 Location: Lock Haven PA

Jim Stewart wrote: I suspect there will be a glut of run out engines on the market when it's time.

"Run out" is a relative term, Jim. For flight school aircraft, TBO is regulatory. Since mine has complied with the service bulletins to raise its TBO to 2000 hours, I will have to major or replace it then, regardless of condition. But, for those aircraft owned and being flown by individuals, it's not the case. So, unless the plane is in commercial service (mine is :( ), overhaul is done on condition, not Hobbs time.

From a practical standpoint, properly maintained Rotax 912s and 912uls can be expected to go 3,000 to 4,000 hours, safely, without major maintenance. That is, assuming that the gearbox and carb overhauls are done at proper intervals (and the 5-year rubber replacement is complied with).

So, how do you know when your Rotax is run out? You could wait for it to fail in flight, of course, but I'd think that monitoring compression, doing spectrographic oil analysis, and cutting open oil filters at every oil change would be a better approach.

As I recall, Rotax ran a competition last year, to find the oldest 912 still in service. They had quite a few entries that were still running strong at over 5,000 hours. Does anyone know what the winning time was?

shasta · Joined: 06 Sep 2011 Posts: 23 Location: sacramento

I am sure there will be a glut of high time engines here in a few years. I think that will be great for the homebuilt guys. Let’s face it, not many years ago two strokes, with 300 hour engines, were the norm. I know I would rather take my chances with a high time 912, which I was monitoring closely. If you figure you can get another 1000 hours, before you need to do anything, you would probably be much better off than using a 582 financially. It should be more reliable, get better fuel economy, more power and you are going to end up rebuilding the 2-stroke a couple of times. Most of the information I have seen shows the 912 being much cheaper than the 2-stroke anyway when you take a 912 at 1500 hours and a 582 at the same number. Fewer rebuilds and so much less fuel and oil.

I was bored last night at work and I emailed a guy about rebuilding a 912. He wrote me back today saying it would be about $1500 in labor. He never did give me an approximate figure only saying that he had legally done several, and that he did not replace parts that did not need it. He basically wanted me to give him a call, which I understand. I am assuming he meant that he usually did not replace the crank. I did look at a parts list online and see that a new crank is about $4500 add pistons and gaskets you are about $7000.

I don’t know much about all of this other than what I have read but I would guess in a few years we might see a secondary market for remanufactured parts. You guys running S-LSA’s will most likely always want new engines or complete rebuilds with new parts but lots of guys flying cheaper AB’s would be happy to have remanufactured parts for their non-certified engines.