What's the deal with gear "chatter"?

[Lessen]

I'm not sure if this has been brought up before cuz I'm not really sure what to search for exactly. But I'm curious about how much "chatter" there should be when I roll my buggy without the engine running. Should it be super quiet or should there be quite a bit of contact noise? When I roll my S3 there seems to be a lot of chatter at the main gear and CB. Is this normal? The gear mesh is really nice (just a few hairs of play) and everything spins extremely smoothly. I'm jus surprised by how much noise there is. whataya guys know? I'll be taking it out for her maiden voyage to do engine break in tomorrow. I want to make sure that everything is squared away before I get it goin. This is the only thing I'm concerned about. Thanks!

 

[mikeburgin]

you may not have enough play lesson, there is normally noise, but not alot like binding sort of sound, when you make the mesh put a normal peice of A4 paper in the gears, once all is tight then roll the paper out, if theres a lot of noise its either to tight or to loose, hard to help u without showing you

 

[Lessen]

ok, thanks Mike. I'll give that a try tomorrow. see if that helps. Thanks!
I'll let ya know. peace.

 

[gdc02]

it's important too the motor is perfectly inline

in the beginning it is difficult to find the right compromise
you have to recheck and recheck

 

[Diver6127]

There's also another trick that I picked up from the guys who rebuild rearends in the te 1:1 cars when they check for backlash on the pinion and ring gear. Get some white out and brush some on to the pinion. Let it dry then turn the pinion and spur together. Check the markings and see how deep the teeth bite. Of course do this after checking it with paper for mesh. The white out will give you a better idea as to how the teeth are meshed.

If the markings are all the say down, it's too tight. If it mostly gone from 3/4 of the teeth it's too tight. If it's almost all the way down but there's about 1/8 of the white out left you got it dead on.

BTW, it's more easily inspected with a magnifying lens.

 

[Lessen]

ok, I've come to the conclusion that it was due to the angle of attack. that's always so hard to tell if you've got it right. I was having a hard time (really hard time) adjusting the angle. Just when I thought I had it smooth it would start chattering again when I tightened down the engine. I did this many times. I kinda thought maybe the engine block was making slight contact with the chassis when I tightened it down. There is a groove below the engine, I thought maybe that was causing it to stay at a certain angle. Anyways, I decided to try n cut a few pieces of scrap plastic and make some mockup shims (for between the mounts and the chassis, NOT between the engine and mounts). So far it seems to have worked well. There is what I would consider to be normal noise now. Sounds like real smooth. It could just be that the plastic shims keep it from sliding when I torque it down. In any case, everything seems good to go now. Thanks for the help!

 

[mikeburgin]

Lessen if they are plastic you may want to take them out again, will act as an insulater between the motor and chassis, not good for engine since it uses chassis to desperse heat.

 

[Lessen]

ahhh... good point. I'll check that tomorrow before I start break in. Just to be safe I took it up to my LHS today just to check about the mesh with someone in person. He said what I had at the time was normal. I feel confident about that now.

 

[niggle]

Lessen if they are plastic you may want to take them out again, will act as an insulater between the motor and chassis, not good for engine since it uses chassis to desperse heat.

I had a similar problem dropping a Hyper 21 into my Swift where the bottom of the crank case was fouling on the chassis. On the Hyper 21 there is a seam where the crank case is cast in the mould. I used a grinding wheel in a Dremel to dress the seam and obtained the proper clearance.

 

[Lessen]

I thought about that too, but I wanted to try something else before I started grinding away on my engine block.

 

[comp75]

Mine was a little noisey at first(more than "normal") I run it a couple times while doing engine break in and it went away on its own. No bad wear or anything either.

 

[Lessen]

Mine was a little noisey at first(more than "normal") I run it a couple times while doing engine break in and it went away on its own. No bad wear or anything either.

yeah, I figured that would happen too. I did take those shims out before i ran it. everything is cool now. I couldn't get it started at factory settings untill I leaned it out a half turn. I ran a tank and a half yesterday extremely lightly, never took it over 20% throttle or so. Only reason I didn't finish the 2nd tank is because of a steering issue. The servo savor adjuster was not high enough and was causing it to bind. During the build I recommend setting that adjustment somewhere around 1.5 - 2mm instead of the manual's stated 1mm from the end of te post. It was starting to get dark too. I'll continue break in today sometime. However, I'm gonna try to richin it a little bit after I get it started..... I would feel better if I could run it at the 3 turns out point.

 

[PiErow]

Ya now you just raised your engine so the box will have toruble getting to the flywheel...

 

[mikeburgin]

, never took it over 20% throttle or so. Only reason I didn't finish the 2nd tank is because of a steering issue. The servo savor adjuster was not high enough and was causing it to bind. .

lesson give it blips of full throttle but dont hold it open, the idea is full throttle gives it full fuel, quater throttle does not, if use blip full throttle no throttle it will keep good fuel going through the engine.

 

[Plaidfish]

I use the wood shims between the engine and mounts trick....I read that in the RCnitro action book I bought a while ago and it helped w/ quick temp changes making the mill run inconsistently.....It really made a difference on my Maxx.....but the book was saying how using the chassis or motor mounts as a heat sink can cause engine performance to be less consitant....I'll have to read it again for the excuse they gave but it worked on my mills....it made tuning a lot easier for me

 

[Lessen]

Pierow, I had taken those off before i started break in. besides, in total it was only 5/100"... uncompressed. also, somehow it got stuck at TDC. my box wouldn't budge it even wth a full charge, I couldn't even get it to move with my thumb until I took the engine out and did it with my whole hand.

Mike- thanks for the tip. The O.S. manual does say that but I think in the later stages of break-in. I will give it a go with some blipping today. I'll do a half tank then start on the 3rd and 4th... maybe 5th and last break in tank if I have enough daylight left.

 

[mikeburgin]

I use the wood shims between the engine and mounts trick....I read that in the RCnitro action book I bought a while ago and it helped w/ quick temp changes making the mill run inconsistently.....It really made a difference on my Maxx.....but the book was saying how using the chassis or motor mounts as a heat sink can cause engine performance to be less consitant....I'll have to read it again for the excuse they gave but it worked on my mills....it made tuning a lot easier for me

Dont know where you read that cause everything I've ever read or understand about the chasis is that it actually works the other way, being a contsant source of heat releif, problem with only using the cooling head is that heat is only removed via the cooling head giving uneven cooling to the engines, causing crank distortion and other weird problems not to mention engine over heating, if you didnt need to release heat through the engine mounts and chasis then everything would be made of carbon to save weight

 

[Lessen]

lesson give it blips of full throttle but dont hold it open, the idea is full throttle gives it full fuel, quater throttle does not, if use blip full throttle no throttle it will keep good fuel going through the engine.

here's what I've done so far. break in