I swapped the gear ratio on my titan to 8.7 and now I can't seem to get engine alignment right. No matter what I tried I can't seem to get it smooth. I've tried turning the screws one at a time till I get resistance and then backing up a bit, while spinning the starter shaft slowly backwards. Tried it with enigne to engine mount screws and with engine mount to frame screws. Seems that after changing the ratio engine alignment is off by ~0.5mm (length wise) the last thing I haven't tried yet is to drill the engine mount holes in the frame bigger. Any ideas on this ??
Oh I added 3rd bearing on the starter shaft too, could this be the culprit also ?
Everything spins very smooth and frictionless till I push the engine up so I don't thing it's any of the bearings. I swapped the clutch cause I though it was the one way on the clutch, clutch isn't hitting the bottom of clutch bell, running quickly out of ideas...
Cheers...

You changed both the pinion and the main gear?

If yes, then I'd look at that 3rd bearing block because I built my Titan with 8.7 gears and didn't have any fit or alignment problem, if you have to start drilling out frame holes then something is wrong.

After reading that Michael had done the same (drilled larger holes to get alignment right) I went ahead and made em 0.2mm larger and what do ya know, got it aligned nicely. It did still feel tighter than it used to be w/o the 3rd bearing but I remember reading from somewhere that with the 3rd bearing it will be tighter (as it is, no play on clutch bell). Then today after coming home from the field after a nice day of flying I find the start coupler really hard to sping backwards with engine at TDC. Well I take the whole thing apart and what do you know... Starter shaft bearning feels crunchy, and even more so when you apply upward pressure to it. Guess I managed to jinx it when I installed the 3rd bearing. I guess this is the reason I was having such a hard time getting engine aligned right was never an alignment problem, but a bearing problem. Just seemed like alignment problem cause the second I pushed the engine in, starter shaft pushed up and applied pressure to the bearing making it feel tight. Oh well, another day, another lesson learned. Next time I have to change any of the bearings in that area I will most certainly rather take half the frame off than just split em. After all it only takes a bit longer and allows me to epoxy bearings to the frame.

What third bearing? Did you leave the prop thrust washer on the crank shaft? If so take it out, because the clearance between fan, clutch and the bell housing will be tight.

3rd bearing is a QuickUK "upgrade" it will prevent the starter shaft from wobbling under load. And no don't have the thrust washer on the crank shaft.

http://www.quickuk.co.uk/acatalog/r_index.htm PN: RD03 about halfway down the page. Though I'm not convinced its really needed if you green locktite the bearing to the pinion it wont let the inner race wallow out a groove in the pinion.