Engine had a detonation event in break in that eroded/vaporized the front leading spark plug ground strap.

Replaced this once I started to suspect it may be why the engine was soft on the top end after brake-in.

After a few 9,000 RPM runs top end power was confirmed good, but oil pressure suddenly dropped.

Found half the front side housing stationary gear dowel pin between the oil pump stages and half in the oil pan.

Luckily, it seems only the oil pump and the dowel pin were damaged.

I will put a new dowel pin in with permanent lock tight and be left wondering if it was the detonation rocking the rotor gear back and forth on the stationary gear or a nasty high RPM resonance that caused the dowel pin to come out.

 

that IS weird. any pics of it? yeah, i'd be very interested in finding the cause. could you maybe have left something loose upon assembly?

 

try putting it in with locktite high heat sleeve retainer.

I have used in in some motorcyctle applications, and in my applications there was lots of surface area, but it took over 5K pounds in a press to get it out vs permanant locktight which came out with a hammer.

 

Yep, the green sleeve retaining lock tight is what I left the auto store with after reading the backs of the packages.

There isn't anything to tighten to hold the dowel pin in the front iron- just a press fit. You could get tricky and modify the thrust washer to be a keeper, but lock tight seems a lot easier :P

I haven't checked the bore to see if it is wallowed out yet...

 

this will happen when you get on it when the motor isnt properly warmed up