Requesting Break-In Advice

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ElocFSU

Member
Messages
25
Location
Houston, TX
Hey guys,

A friend and I just received our new Savage X 4.6s. We started the break-in process today. Went well for me - I completed 2 idle tanks with wheels off the ground and finished my third tank with wheels down and half throttle bursts. Looking good so far (I think, but I'm no expert), although I do want to share some observations and ask if you had similar experiences. I'll do that in my next post, since there is a more pressing issue.

My buddy's luck was not as good as mine. Even though we checked his gear mesh to the best of our abilities before start up, his truck managed to strip the spur gear about 5 minutes into his first tank at idle. Disappointing obviously. I saw that something was wrong when all wheel spin stopped. I looked closer and saw that the clutch bell was spinning but the spur gear was completely still. The engine sounded fine but once I saw the spur gear troubles we shut it down.

So, a few questions. First off, should we have shut it down? Personally, I figured you should never continue running if you see an obvious problem. Engine sounded fine but, as I say, the clutch bell was no longer engaged with the spur. Hope I made the right call. Guess the counter argument could be that the spur gear was already done for, why not continue break in? Not sure what would have happened in that case (with no mechanical load on the engine).

Next, how should we proceed? Obviously we'll change the spur (we ordered a few spares) and try to make sure the mesh is good. Then I figure we'll restart break-in, basically from scratch. Anything else to consider?

Lastly, given what occurred, is there anything else that might have been damaged that we need to check out before the next attempt? Or is it likely only the spur and we change it out and proceed?

Thanks in advance. As I say, I'll share more from my break-in experiences soon.
 
My son bought a Savage X 4.6 a few years ago and had the same thing happen. I think the mesh was a bit tight from the factory so with a new spur I reset his mesh and all went good until a jump broke the front diff the same day :)

Here is how I set mesh, I loosen the 4 :ercm: mounting bolts and tighten one just enuff to allow me to shift the mount a bit, then I hold the clutch bell with 1 finger and slowly rock the spur allowing just a slight tick of play, when is the way I like it, all the bolts are tightened down, then removed 1 at a time so I can locktite them securely...

so start with a new spur on your buddies rig and continue the breakin process according to the manual...

Keep in mind the new spur gear will also need a slipper pad (usually included) because it is stuck down to 1 side of the gear..
Good Luck with the new toys.....
 
Yes you did the right thing. I also had the same thing happen to me when I was breaking in my savage x 4.6. Called hpi they sent me a brand new hardened steel Robinson racing spur gear.
 
Yes you did the right thing. I also had the same thing happen to me when I was breaking in my savage x 4.6. Called hpi they sent me a brand new hardened steel Robinson racing spur gear.


HPI sent out a Robinson Racing gear as a replacement part? I find that a little hard to believe. But if it's true, wow! Didn't know they were affiliated.
 
Yes they did when I got it is was like that's kinda pointless without the clutch bell.
 
Thanks guys, great info. Hopefully we'll replace the spur tomorrow and my buddy will be back on track. I haven't applied locktite to any of my mounting bolts but since my mesh from the factory seems to be quite good that's probably my next move.

I have seen the Robinson steel spur gears and am interested. But after a bit of reading, I kind of like that a fairly cheap spur gear is the weak link in the drive chain. Maybe down the road when I'm more familiar with the rest of the drive chain components I'll feel more comfortable, but for right now I'll be happy if we can change his spur gear and get up and running again without any other drive train parts having been damaged.

Will let you know how it goes.
 
Before I forget, here are a few other observations from today's break-in work. Interested to hear if this sounds normal and if others have experienced same.

Idle Speed - I was surprised by how high the idle speed seemed to be set. Almost right away the tires were spinning at reasonable speed. As I moved through tank 1, it got faster and faster to the point where I got slightly uncomfortable. I started dialing back the throttle trim to compensate. Eventually found my throttle trim at the lowest setting and the truck seemed to want to turn the tires faster still. Eventually, not knowing what else to do and worrying it was too fast, I adjusted the idle screw to slow it down. This seemed to get it back under control but I'm hoping it was ok to do or if I should have done something differently? The manual says surprisingly little about wheel spin and how fast it should be and what to do if it is too fast.

Unpredictable Idle - I know it's break-in and some rough running at super rich settings is to be expected, but man, again I was surprised. It was a bit all over the place in those first 2 tanks. It seemed to rev up high sometimes, then would slow down, then run smooth, then run real rough, seemingly randomly with no input from me whatsoever. Was a bit nerve wracking.

Fuel Line Routing - Probably should have noticed this up front on my buddy's truck but his fuel line was touching his engine's heat sink. We eventually saw quite a few bubbles in the line and I got worried that we were super heating the fuel. We shut down and managed to rotate the fuel inlet on the HSN body and I think it was better after that. Till his spur gear went, anyhow.

Failsafe - The radio failsafe was not set on either truck from factory. We tested and noticed it was easy to configure. It thought that was odd.

Roto Start - I thought the roto design had changed (from a drill style unit to more of a compact design with a built-in breaker). Maybe I had that backwards. Both of these trucks came with drill-style units, and I don't think they have the breaker protection. Also, there are multiple clutch settings (1-3, I believe) but no documentation that I can find on which provides more or less drag.

That's probably enough for now. :)
 
Hey guys,

Just checking in to see if anybody has some thoughts on the break-in process thus far. Will probably be continuing with round 2 this weekend.

As a side note, the RC gods have gifted me with some good fortune - I was telling a work buddy about the trucks and he gave me a Duratrax Warhead. Came with all kinds of goodies - radio, glow igniter, even a starter box. Was purchased in 2006 but seems to be in great condition. Looking forward to getting it cleaned up and seeing if I can get it started. Seems very similar in design to the Savage from what I can tell. Even has a vertical plate chassis. Would be interested if anybody has some thoughts or advice on that.
 

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