Hi All,
I recently acquired a brand new Irvine 53 Mk2 (Japanese version, silver cowl). Ran it in on bench with about 1L of fuel per instructions, got the ABC lining nice and warm for short periods etc. All absolutely flawless. After run in would turn over nicely and freely with a finger and had a nice compression.
I put it in a model and tried to start it, it popped and looked to start but I noticed the prop was slipping a little so obviously stopped to tighten the lock nut. Issue was that the prop was locking against the spinner backplate but not the prop hub on the engine allowing the latter to rotate slightly. (I ran it in without a spinner on my bench).
So, the issue... I tightened the prop nut until the spinner backplate and prop hub actually locked. This required more torque than I would normally expect but done by only a small 6" spanner so I didn't think excessive. However, now when I go to turn over the engine it is stiff through the entire cycle to the point you can hardly detect it going over TDC. In no way does it feel like it would be safe to start.
I've check it without spinner, e.g. just prop on hub + nut and exactly same stiffness so something has changed mechanically in the engine. I've check there was no contact with the cowl inducing friction and I've checked the engine wasn't flooded (it wasn't and did turn over, just suddenly very stiffly).
So, I've broken it - but exactly what have I done!?
Edited By Scruffmeister on 16/09/2017 15:50:34