Smoked a crank...suggestions?

[showjyr]

So the owb chewed into the crankshaft on my 3.3. The truck it's in is less than stellar but it's the first truck I had and is good to thrash on...it's also sitting on an acncm chassis so it's worth keeping. No idea how many tanks have been through the 3.3 but it rips. I also tore the carb boot so I need a new one.

What's my best option send in the mill to traxxas for the exchange program, buy a crank and do it myself, or....?

 

[Snook Man]

The OWB does not fit to the crankshaft, it fits on the starter shaft. Just replace the starter shaft (and the backplate if needed).

 

[showjyr]

Well I guess it's not the crank just the little starter shaft that turns the crank.
I stripped the whole engine down...sooo while it's apart

Get that part right from traxxas or what?

I'm going to port the sleeve...how much pinch should it have? Maybe get a new sleeve?

Any mods I can do to the crank or mill?

New bearings and wher/what ones?

I know that's a lot of questions but I have time so I might as well do it...thanks in advance.

 

[knall]

Ceramic bearings would be nice if your in that deep.

Personaly i would just replace the wwb and shaft stub. Ebay is your friend

 

[2revo1maxx]

Get a owb and starter shaft and rip it! It's only a 3.3.

 

[REVO-5309]

check the bearings to see if there wobilly. if they are just get the stocko replacements, when the motor starts failing when its warmed up then u need a new piston/sleeve. till then just bash it till it dies. pulling the motor apart isnt that big a deal, gives u something to do.

if something likes the bearings give and it takes out your crank then maybe swap the motor over. thats worse case like what happened to me

 

[showjyr]

Soooo I figured I had everything apart and all looked well I might as well do some experimenting...it's only and old 3.3 anyway. I ordered a new owb, starter shaft, back plate, pull start, head shims, and carb, all should be here Tuesday.

In the mean time I degreased everything, wire wheeled the whole shabang, ported and polished the sleeve, ported and polished the crank, trimmed some weight from the crank, as well as scalloped the end. Now from what I've read this can change the timeing (although I'm not sure how as the opening/angle of the intake ports on the sleeve were not altered)...I'll wait until the new ones arrive but the head shim looks to be .30, would I benifit from going thicker or thinner? Running 20% and an OS LC3

 

[wacmartin]

I really want to hear how this turns out for you! Sounds like a very fun and interesting experiment. I think your going to have alot more power here.

 

[showjyr]

I've created a monster!!! It needs some tuning but wow...with a near perfect tune before it was pretty ballsy but I've easily got probably 30% more power on tap now...borderline out of control in a small area. I'm taking it fairly easy but it's pulled a wheelie in second gear a few times and it'll flip over if I punch it from a dead stop.

 

[showjyr]

Well I've run 7 tanks through the rebuild and it's still screaming. Got a decent tune and running between 210 and 220...little finicky with the idle and still likes to die here and there but I'm gonna chock that up to my tuning. Also noticed a fair improvement in fuel efficiency...less weight, better fuel/air ratio I'm guessing.