that falls in the ''any number of things" category,

either way , not "the norm"

Nope...definitely not the norm

What would cause it to happen twice in a row. Two different engines. Piston through the sleeve after 4L

No scratching on the crankshaft. running nitro x 25/11. Run in on a bench for 6 tanks at 100-15degs c. preheated with comp heat.

Snap some pictures of the internals for me...... crank,sleeve,piston,button.....hard to say much until I see what it looks like inside...

First off simply doing 6 tanks on a bench then racing the engine is not a complete break in. Look on the engine break in thread at the top and do that. it takes about 1/2 gallon of fuel to get ready to race tune an engine. 6 tanks ain't a half gallon.

Byrons 30-11 30-9 or 30-8. For break in or does it matter?

I would HIGHLY recommend using race 3000 (11%) for life of engine , really hot days switch to pro driver 3000

I have a gallon of Byrons Fuels Race Gen2 30-9% How much castor oil should I add for break in?

I would usually add 1.5 oz / gallon

That will bring you up to 10% oil which is great, kind of the best of both worlds. I have been running my Plus 4 using the 30/9 with castor added for the last 5 gallons and not a problem at all. Runs at 270* to 280* with good smoke, run time and power. Im sending it for a light pinch after my next race day just so I know it will make it through the rest of the season.

With Byron lube booster, would I use the same amount for Powermaster 30/9?

Do you use an air filter on the engine on your bench?

Rex

I seen someone post that they use this Castor oil. Is this ok to use?

http://www.cvs.com/shop/product-deta...l?skuId=209437

Well I hope so cause I put 1.5 ounces in my gallon.

For break in I use a gallon of 16/12. After always Byron 25/11.