V-Spec break-in is pissing me off, beefier bump box needed?

[Amoeba]

So I've got this shiny new .21 V-Spec for my RC8. Now that nicer weather has decided to visit the Seattle area I figured it was time to install it and start the break-in process. I put in a new fully-charged 12v in the OFNA 10250 startbox, got all the posts lined up perfectly, heated the V-Spec up with the heat gun and got to work.

Or not.

The pinch on the V-Spec is so freakin tight that when it hits the first TDC rev on the bump box all I end up doing is shaving rubber off the bump wheel. I've tried multiple tweaks & adjustments to ensure bump box motor is at full speed before flywheel engagement and I (once) got it to turn over about 3 revolutions before it was rubber dust time again. I can apply more pressure but the bump motor torque gives up before the V-Spec pinch does. I can rotate the flywheel by hand though it is very tight (but smooth) so it's not "catching" on anything physically blocking rotation. I've ordered a new rubber bell for the bump box.. I had to, I've now got grooves worn in mine from dicking with this.

I need a beefier bump box. This is pissing me off. Someone recommend the end-all be-all of OMGTORQUE! bump box to me. I'll get this damned V-Spec broken in if it kills me.


Note: Switching to pull/roto start not an option. There's no post on the con rod/shaft of the V-Spec for that to work. It's bump only baby!

 

[samrsnow]

Try putting some WD40 in it to lube it up a little more. Or some AFO. Then heat the poop outta it. Its gotta work after that...

 

[Amoeba]

Try putting some WD40 in it to lube it up a little more. Or some AFO. Then heat the poop outta it. Its gotta work after that...

Sorry, thought that was a given. Been there, done that.

 

[samrsnow]

Dang bro. I don't know what else to tell ya! I guess getting a better starter box might be the only way to go.

 

[robmob]

I have a Ninja .21 that was a bitch to start with the starter box even after I broke it in on a break-in stand.

The first few times I started it on my box I heated the engine case to 200 degrees.

After that I was able to get it started without the gun, but I had to make sure the piston was just on the negative side of bottom dead center so it had a little momentum when I pressed it down on my starter box before reaching the top.

Here is the box I use.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCLD9&P=7

 

[Amoeba]

I have a Ninja .21 that was a bitch to start with the starter box even after I broke it in on a break-in stand.

The first few times I started it on my box I heated the engine case to 200 degrees.

After that I was able to get it started without the gun, but I had to make sure the piston was just on the negative side of bottom dead center so it had a little momentum when I pressed it down on my starter box before reaching the top.

Here is the box I use.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCLD9&P=7

Yeah, I've been trying the just past TDC trick to get some momentum as well but still no luck. I'll see how high I can get the engine case temp up but I've gotten it to almost too hot to touch and still it taunts me.

Is that the OFNA #10249? It doesn't specify what motors it has in there. I'm curious if the OFNA #10244 Truggy box would have better torque for high compression engines. That one runs two 775 size motors.


EDIT: Rob, what break-in stand are you using? The Hudy?

 

[neobart]

The 10244 will turn most anything over. It could turn over my STS when I broke it in, and that beeech was fornicating tight.

 

[robmob]

I used the RD Logics stand.

Not as fancy as the Hudy, but it gets the job done at a cheaper price.

http://www.rdlogics.com/cgi-bin/category.cgi?item=15000&type=store

 

[Amoeba]

I used the RD Logics stand.

Not as fancy as the Hudy, but it gets the job done at a cheaper price.

http://www.rdlogics.com/cgi-bin/category.cgi?item=15000&type=store

Hrm.. Not too shabby. You just pop on the propeller & adapter and you're good to go eh? I may pick one of those up if the OFNA Truggy bump box I just ordered isn't up to the job.



DOH. I just thought of something: add a head shim to lower the compression for the break-in. I'll have to see if I've got a 6k or 8k shim somewhere and try that....

 

[robmob]

You can loosen the plug as well. Once it's started you just tighten it down.

 

[superdave2]

by chance do they make a harder rubber for the wheel for the bump start like a rubber/plastic wheel if so that might help not sure tho it might just eat it up faster not sure