Losi 3.4 locked at TDC?

[alien13]

Went for a run up and down the street, and it just stopped at about half throttle. When I tried to start it again, it wouldn't turn over at all. I took the drive rod out of the roto start wand, put it in a screwdriver, reefed on it as hard as I could with the glow plug out and the exhaust off, still nothing.

It also fried a brand new glow plug after about 60 seconds of runtime.

 

[olds97_lss]

Well, you may have snapped a con-rod. I'd pull the engine and take the backplate off to look inside to see what's going on.

Or, you can try to gently rock the flywheel back and forth to see if it will break loose, but keep in mind, if it is a shattered con-rod, any rocking/moving of the crank will just result in gouges in the inside of the crank case.

 

[alien13]

Ok thanks. Tomorrow after work I'll pull the backplate off first and see what happens. There's less than half a gallon on this thing, and I think I've only had it for less than two months, so I'm getting pretty fired up about it.

 

[olds97_lss]

Well, rest assured that Horizon will more than likely take care of you if the engine doesn't appear abused. Better get on it as soon as you can though, the bashing season has started!

 

[alien13]

Well, rest assured that Horizon will more than likely take care of you if the engine doesn't appear abused. Better get on it as soon as you can though, the bashing season has started!

I know! After finishing the body for my Muti, I pulled the motor, cleaned up the chassis and parts, pulled the carb and sealed it, got it all put back together so i can run it tomorrow! Now with the Speed-NT, I'm down to one truggy. Next year I might have to get a third one. Thinking about electric short course so I can race.

 

[alien13]

Called Horizon, sent in my repair request, now my printer won't print (no ink) the form I need to send with it, and I can't email the form to my friend to print it, and I can't figure out how to bring up the page so I could just go to his place and do it.

 

[olds97_lss]

I think I see your problem... there's way too much dirt on your engine mounts... tsk tsk...

Man, that sucks! I guess it really is a clone of the TRX3.3! That engine is notorious for doing what yours did.

 

[adbmodifieds]

looks like it has the same damn full circle crank too!

 

[olds97_lss]

"full circle crank"? What's that in respect to?

EDIT:
Think I figured out what you meant, looked at a few cranks. Why does it matter if it's a full circle crank or not?

vs

 

[alien13]

looks like it has the same damn full circle crank too!

Huh? Wanna let me in on this one?

 

[alien13]

YAY, It's on it's way back!

At this point, I am impressed. Last Tuesday, I sent my repair request, Wednesday I sent my motor in for a broken con-rod, Thursday they received it. The turnaround time listed on their site says 6 business days for engines. This morning I checked the status. At 8:13 is was assigned to a tech, at 9:43 it was ready to ship, at 3:55 it says Work complete, Product shipped, and I got a tracking number in my email for Fed Ex Ground, meaning I should have it in my hands tomorrow.

Wow!

 

[olds97_lss]

You know... since that thing looks so close to the TRX 3.3, I wonder if the DD con-rods fit:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXVHW4&P=ML

Beefy SOB's, a bit pricey though.

 

[alien13]

I got it!!! Secretary at work came looking for me with a box, I opened the box to find a BRAND NEW Losi 3.4. The tech said that due to the nature of use, this type of breakage was not covered by warranty, but because of the short period of time that I had it, and customer courtesy, he put my flywheel, clutch, and roto start on a new engine. FREEEEEE!!!

So I stopped at my lhs, picked up a gallon of fuel, came home and started breaking it in. In the process, the clutch spring broke, again, and my roto start wand pinion gear came loose, so I had to tear that thing down. But now (break-in per Losi intructions) I'm a little over halfway through the break in, and it's already pulling wheelies.

I'm back in the game!

Also, my lhs FINALLY got my parts for me to complete the pivot ball steering on my Mutilator, so I need to make time for that one too.

 

[Scrogg]

Don't run it overly rich. If it is blubbery or hesitates to accelerate, lean it out.
2 major causes of broken engines during the first gallon are running too rich and revving it too high too soon. You can let it rev out for 1-2 seconds, after that you need to back off the throttle. Once the mechanical pinch is gone, then you can let her scream but not for long.
It takes a high end engine to turn 30K rpms non stop. The Losi is not one of those.
@Olds, the 3.3 crank has a lot of excess material and very poor machining. A little extra machine work does wonders.