912 Big Bore

[WWhunter]

mtgsxr,
I have the ExtraPerformance piston upgrade in my 912. I have been researching various options for my engine due to what I feel is excessive oil useage of my engine. Having spoken to a couple other guys that have these same pistons, I was told this is common with the HC pistons. Any truth to this??? Heck if I know but I am pretty sure I am going to eventually purchase the Big Bore kit from Hal.
My engine is 1996 vintage with less than 200 hrs. TT

[mr bill]

Just got a call from Hal Stockman about dyno testing of his big bore kits. He tested a stock 912 ULS (1352 cc) without the airbox and got 93 hp; Rotax says 95, which is pretty close. His low compression big bore kit (1484 cc) for the 912 ULS gave 106 hp and the high compression kit gave 114 hp. He will be testing the bored out 914 crankcase with 1622cc cylinders next.

[WWhunter]

Mr. Bill,
Really appreciate the update. I have been waiting to call Mr. Stockman for this info. I had called Hal several weeks ago and knew he was going to get his kit dyno'ed soon. Guess you just saved me a call.
I am torn between getting the HC or the lower compression kit but overal I think the low compression kit makes more sense, especially cost wise since I have an older motor. Hal suggested I change several things if I went with the HC kit and in the end I would have a lot of additional money invested for what ends up being 8 HP. It would be several hundred dollars per HP along with the need for higher octane fuel.
As son as I can get my taxes done I am hoping to give Hal a call and order a set.
I have my cowling off the plane, and having ZERO experience with the Rotax, just looking at the maze of stuff is almost intimidating. I have tried to find someone local to look over my shoulder but there is no one around my neck of the woods that works on Rotax.

Thomas,
Is there any other info on the FI you sell? I have looked at your site but am unable to find a price or any info on what is included or involved with the conversion.

[mr bill]

Where is Lost, USA? My background has been with Continental and Lycoming, so this Rotax was a first for me. Go on line, download the free manuals and take one system at a time, fuel, cooling and oil. The cylinders are held on by four bolts each, but use the cylinder alignment tool (or a simple flat plate) and follow the manual for torque and torque sequence info. Not that complicated really and no special tools required. The Lockwood website was a big help as was talking (mostly listening) to the Leading Edge Airfoil people. They also rebuilt the gearbox and installed a new flywheel.

[mr bill]

He gives his location as Lost USA, I have never heard of it.

[WWhunter]

LOL...ok, Mr. Bill, I am actualy NW of you at the moment. I am north of Park Rapids, Mn. I have a strip, hangar (unheated..Brrrrr) and am currently trying to build a house for our retirement. I had forgotten I put that as my location when I signed up. Being a military family we were never in one place that long so I was always 'lost'.
Keith aka WWhunter

[mr bill]

There must be someone near you (where ever Park Rapids is) with a Rotax that can help. In any case, just take one thing at a time and you will be ok. I do know where Minneapolis is though.

[WWhunter]

I am 200+ miles north of Minneapolis. Basically in the boonies. If you look at any map of the US, follow the Mississippi river all the way to the very begining. My place is SE a couple miles of that point, the Headwaters of the Mighty Mississippi is but a foot deep stream that begins its flow starting at Lake Itasca.

Mention Rotax up in this country and they think you are speaking a foreign language, (I jest of course) but they are very rare around here.

[mr bill]

Well, if you have a problem, throw the engine in the back of your car and come on down. Leading edge airfoil is a short distance away (in case we screw anything up). Looked up your town and it appears to be a really nice place to live. It has a good sized airport.

[BigJohn]

I am working with Hal & Wayne testing the newest Big Bore XXL, 1622 CC this unit requires modification to the Case & Heads, Very similar to the Big Bore 1484CC High Power unit but has larger Bore, thicker cylinder walls slightly lower compression, higher torque, Dyno shows solid 114hp at 5800 and 113 ft lb torq at 4860. I will be posting the test results as it compares to the 100 hp 912uls which really only shows 93hp on the Dyno. I can tell you already had to add 3.25 degrees pitch in 70" Warp to get the static run up where it needed, thus far all ground running, should put in the air if all continues to check out tomorrow.

There will be an ad coming out in Barnstormer soon with the various units already available and prices. I have been flying with individuals flying both the 1484 cc 105hp and and 1484 cc High Power 114hp. These units are high quality best I have seen and superior to stock Rotax and have made significant improvements in the planes performance, No issues, No Oil usage and run cooler.

Will keep everyone posted as the testing on the 1622 cc unit progresses.