i another thread ive been stressing about the bolts on my muffler. anyhoo, i blew my thunder tiger 46 about a month ago and mailed it to ace hobby. (they do warranty work for thunder tiger). i finally got ahold of them on the phone. not only is my engine fixed and being shipped at no charge, the guy i talked to about the muffler bolts informed me that thunder tiger does not make the pro 25 any moore. he went and checked inventory and found that he had 2 left told me he would put them in with my engine, no charge and have a nice day. (thanks for your help w8ye) but a real nice solution to 2 problems yea!!!

That's great. How lucky can you get?

This doesn't happen every day.

Enjoy your engine,

Jim

Just out of curiosity, what failed on the TT 46 Pro? I find them pretty bullet-proof. The only weakness that I have encountered is the rear crank bearing & that is a common problem on just about every brand of BB engine if you keep them constantly at very high revs. My rear bearings seem to last ~ 100 hr of very hard running.

That's not bad if you're stressing them. Many of us boaters replace bearings every season, whether they need it or not. Better to just spend a few $ on new ones than have one go out and ruin a weekend.

it was the rear bearing. but he added that the casing actually failed. i wonder how often i need to change bearing in my engines i did not know that was something that needed to be done?

When you say casing -- do you mean engine case, or bearing cage? The bearing cage, rather than the ball-race, is usually the culprit.

There isn't a lot that you can do except to use after-run lube to avoid rust, & limit the amount of time at very high revs. The rear bearings in most 40-46 size sport engines are limited to a max of ~16,000 RPM. They will survive for a reasonable time at that speed, but if you run there all the time (some engines develop peak power higher than that) it is a good idea to keep an eye on them & replace them at the first sign of wear. The bits from a collapsed cage can cause a lot of damage.

If you are going to run steadily at very high revs, ceramic bearings might be a good idea.

it was the caseing that holds the bearings. i guess i need to learn a little more about the engines. a guy at the field took off the back plate and i could see the bearings but they where behind the crank shaft.

OK -- that sounds like the cage. It is the usual failure point. The cage holds thge balls within the races at a specific separation from each other. The balls rub against it a bit while the bearings spin & eventually the cage wears through in places -- scattering bits of metal into the interior of the engine. Some of these bits get sucked (pushed) up into the upper cylinder during the induction process.

If you are lucky, they don't get caught by the piston as they pass through one of the transfer ports, or in pass out through the exhaust port. They ding up the piston crown & the underside of the cyl head. The engine will survive that damage.

However, if they get caught by the piston while passing out of a port --- goodbye motor.