can't dial indicate new motor for Stratus

[Wayne]

I wanted to post this to maybe save a few people some time. I went to put a new OS-91 SZH engine in one of my new Stratus's today. The project should take about an hour....

I put the fan on, and went to dial indicate it. For the life of me I could not get better than 0.005, which will not work. :arggg: I pulled the fan, and the crankshaft has a run out of 0.0025 right where it steps down above the key cut, but below the threads.

The morale of the story is, if you can't get it to dial in, check the crankshaft. I did this test with the piston/sleeve out, so I know there was no drag or anything giving me bad readings. I should have dialed the crank first to see if that was straight, but I wrongly assumed it would be straight!

Wayne

www.flymha.com

[mace]

Wayne,
So are you sending it back or were you able to deal with it after knowing it was Crank?

Mace

[flyinfool]

I hve also seen someone almost pull his hair out till he found out the new fan bushings wre out by .002

[christoffer]

I have the same problem with my SZ the runout on the stepdown is
0.016, thats quite a lot.
The swedish OS-distrubutor calls it normal bearing play...
I'm not satisfied with that answer.
//christoffer

[Wayne]

My solution is to send it back. The crank is hardened, and would be almost impossible to get straight. It's been my experience with hardened parts that even if I could tweak it right, as soon as it spooled up and vibrated it would go back to where the original bend was.

1.7 is way too much. If you look closely, the bend/tweak I suspect is almost directly inline with the key way cut that we don't use. When they cut that, maybe they heated it up if that bit was dull, but who knows. I do know when it's off by that much you won't get the fan dialed in for sure.

I'll let you know how it works out, I'm a bit concerned, but the first motor runs like gang busters!

Wayne
www.flymha.com