Zipper big bore

[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.

[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