Zipper big bore

[stevek7m]

Anybody have any new updates on the 912 big bores, zipper or edge, especially the 1622 big bores?
Thanks, Steve

[Av8r3400]

I love mine. 500 hours and counting flawless service!

[Jerrytex]

I emailed Zipper Big bore about a month ago. Never heard anything back. About 3 weeks ago I emailed them again, and Jay called me. He is more of the sales guy so in my situation, he thought it would be best to have Hal Stockman call me. That was 2 weeks ago and I haven't heard anything from either.

So I guess an update would be....they are not easiest to get get ahold of.

I have heard good things about Zipper bigbore, hence the reason I called but I am bummed about the lack of response and communication especially when I am ready to spend money to get my engine going.

[avidflyer]

A long time member on the AvidFoxFlyers forum has a set listed for sale. Here is part of his add. JImChuk

For sale Zipper kit piston and cylinders 105 hp used 3000 USD PLUS shipping. 274 hrs will include new pushrods seals

[Shadowrider]

Have you tried Mike at Stolcreek? Seems very knowledgeable and he does big bores.

[Lawdog]

I've been in touch with Michael at Stol Creek Aviation located near Whitewater, Kansas. He is very responsive, and very knowledgeable. He does Edge Performance big bores, and most other engine work. Check him out. easy to find via google.

[stevek7m]

Yes I actually bought the 1484 kit from Mike at Stol Creek, but was actually thinking of selling it and going with the 1621 kit, just curious if that bigger bore was still reliable as smaller kits?
Steve

[Jerrytex]

I talked to Mike as well. He mentioned that he also has take off cylinders from 912 ULS engines that were upgraded. They will fill the UL. Said it gives 95 hp. This is a 50% cheaper upgrade.

I have a 1994 912 UL. brand new never run, still on the plywood from the original crate. But, it has been sitting untouched. I am on the fence about using it. It will need a teardown inpsection and I think a Stator replacement? (SB I think) Weighing all my options.

Steve, if you go with the bigger kit, I might be interested in your 1484 kit.

[stevek7m]

Jerry, this is the 114 high compression kit, don’t think you would want that on the UL 80 horse.
steve

[Jerrytex]

Gothca. Thanks.

If I do use this engine, the lower compression kit would be the way to go.

[avidflyer]

I'm not sure that early of a 80 is a good of a choice for the zipper kit. Some one was just telling me today, that 2006 and newer is better. And wasn't the engine Hal Stockman blow up on the way to OshKosh an early 80 HP engine. The main guy at leading edge told me that these engines are generally pretty good about sitting for long periods of time without corrosion developing under normal circumstances. I did have a never run early 90s 582 and when I took it to the mechanic to inspect it and reseal, he said the assembly grease was all dried up, and would have caused problems if I had just run it. In fact, I took the gearbox off, and it seemed like the front bearing was corroded, it seems to not run smooth when I spun it over. I sent it to Steve Beatty at Airscrew performance, and he cleaned it up, and the bearings were fine. It was just the dired up old assembly grease. Fresh oil, and it was good to go. Just some other things to consider. JImChuk

[Av8r3400]

500 hours and counting on my 1997 model 912UL with a 105 hp Zipper Big Bore.

Not one ounce of trouble. Thoroughly endorsed by Hal Stockman.

Would I put a high compression version on this engine? Probably not without doing Hal's through-bolt modification.

[bbs428]

Agreed! My early 912ul has the 105hp big bore kit and cam. For my peace of mind, I had Hal do his hd mod which though-bolts the case. Hal is a gem to work with. Real happy with his work.

Never had a problem reaching Jay or Hal on the phone. Holidays and covid could be an issue atm.

[Jerrytex]

Brett, what does the through bolt mod look like?

Also, Curious to know about which SB's you did. The Stator and fuel pump? I called Lockwood aviation and they basically told me I had a boat anchor.

Anyone know of a source for the newer stator?

I had a 1994ish UL in my KF 4 and it ran like a top.

[Iowa 67]

Hey Jerrytex, how much would you sell your "boat anchor" for? If you decide to not use it I may be interested in it.

[bbs428]

Brett, what does the through bolt mod look like?

Also, Curious to know about which SB's you did. The Stator and fuel pump? I called Lockwood aviation and they basically told me I had a boat anchor.

Anyone know of a source for the newer stator?

I had a 1994ish UL in my KF 4 and it ran like a top.

I doubt your engine is a boat anchor. Lol. Probably want to sell you a new engine...

Hal explained to me that mid 2006 Rotax 912 series came with a heavy duty case and other improvements notably the through bolt case and rocker shaft improvements for better oiling. He does this to the high hp zipper engines if needed.
Tbh It looks about the same as it did before but with the bigger jugs and bolts!

Gearbox was also gone through and a slipper clutch installed. All hoses and rubber boots were replaced. Hal ran it on his test bench and adjusted the carbs before shipping it back to me. So it's literally a new zero time engine. I bought a new fuel pump and hd starter from Hal as well.
If your buying a used engine with no log books imho you have to go through the motor/gearbox as your life depends on it. I had little experience with this engine so I had the work done by a pro.

I'm looking at an alternator upgrade but still researching. Maybe someone can chime in on that.

[fastflyer]

Brett, what does the through bolt mod look like?

Also, Curious to know about which SB's you did. The Stator and fuel pump? I called Lockwood aviation and they basically told me I had a boat anchor.

Anyone know of a source for the newer stator?

I had a 1994ish UL in my KF 4 and it ran like a top.

Lockwood told me the stator issue was insulation chafing through and installing a thicker insulation sleeve was satisfactory.

[Dusty]

I have just installed one of Hals 104 hp kits, this is an amazing upgrade,.
A few questions
1 has anyone done a before and after cranking compression test, my pressure is 145 psi I didn't do a before upgrade comparison.
2 the reason I am asking is we weren't happy with the amount of valve shrouding with the stock 80 hp heads, does everyone leave these as stock?
The heads were cnc machined to be more like the 100 hp heads, this requires a small cutting of the heads to restore stock pressure.
This was a bit of an educated guess ,also valve geometry was taken into accoumt.
BTW we set the ivo 72 inch prop to 5100 static with the original setup. After the upgrade I could easily exceed 5800 after an hours breakin
I'm looking forward to getting some more testing and solid performance numbers