TRX 3.3 block question

[david_viny]

When you take the carburetor off and look inside where the carb sits, almost were the crank port is, is there supposed to be a tiny hole going towards the front bearings? Looks like it was machined, but seems kinda weird. Don't remember seeing this on other motors. Possibly a inner bearing lube hole?

Thanks
-Dave

 

[Scrogg]

Yes, you are correct.

 

[david_viny]

OK that makes sense, thanks!

 

[jerry7007]

i wonder if you could drill the hole a little bigger, it always seemed a little small to me.

 

[Scrogg]

I would not, it may affect the tune of the engine. Front bearings where never a problem on my 3.3's. Just the cheap main bearings, that little engine turns A LOT OF RPM's and makes good power when tuned correctly.

 

[Suicide]

yes it does and its a nice cheap mid-small block motor. It kicks A## in my revo.

 

[Scrogg]

My 3.3 was definitely faster mid to top than my O.S. 21 TM.

 

[Suicide]

seriously i can kick the guys butt at my lhs. he's got an os 21 tm in his. but he races 1/8 with his revo, I'm gonna stay in 1/10 class though

 

[Extreme RC Mods]

The little hole behind the front bearing is a oil return hole. As the engine runs, a little bit of oil will make it's way past the seal formed between the block and crank and make it's way to the front bearing for lubrication. This constant yet minimal amount of oil needs some where to go or it will leak out the front bearing, that little hole will suck it back into the engine as there is always a negative sucking action just under the carb. If this hole was to get plugged the result will be an oily mess leaking out of the font bearing.

On a side note, the front bearing does not seal the engine, the seal is made just behind the front bearing between the crank and block. The tolerance is very small and when coated with a film of oil, it creates the front seal. I hope this clears up a few things for you.