Stock Muffler Problems

[MotorOil]

I've had my Revo 3.3 for about four weeks now and the stock muffler has broken twice, each time after about two weeks (after running through about 2 gallons a fuel -- 1 gallon every two weeks).

This has happened both times at the same spot -- where the pipe attaches to the manifold block (i.e. the part with the two screw holes that attaches the whole assembly to the cylinder.

It looks like a heat and metal fatigue break. The truck has never been crashed. Each time when it broke, the truck was being driven straight and level at low speed. The first time was while it was being driven on grass, the second time, just this afternoon, while being driven down my driveway at about 5 mph, tops. The engine just started making a lot of noise. Upon a closer look, I found that the pipe was detached (again) from the metal block to which it is supposed to be attached.

Has anyone else had this problem? The first time I went into the hobby shop, they called Traxxas and I got a free part. They said that if it happens again, I will have to eat it. That seems ridiculous, since it is an expensive part and I don't think I should have to pay for a new part every couple weeks because of what seems to be their manufacturing/engineering blunder. A muffler pipe should not be breaking so frequently and so easily, especially when the truck has never been crashed or been jarred hard enough to cause such a break.

P.S. This is not my first truck. My previous truck was a DuraTrax, which was crashed head-on into a brick wall so hard it looked like a pretzel afterwards; and, even though it was the original stock muffler on a two-year-old truck, the muffler pipe on that truck held together and did not break on that crash.

 

[avengedanarchy88]

muffler

I hav a t maxx 2.5r and I've had the same problem like 4 times. And same thing first time I got a free part and had to eat the rest. I ended up going with the traxxas blue anodized muffler and that seemed to help hasent broke yet.

 

[revo_rob_1984]

try thread lock on the screws

 

[Suicide]

get a one held on with a spring and cut the ez start mount to fit. it worked with me on my revo

 

[Revo3.3Racer]

It sounds like your screws which hold the exhaust on are vibrating off, which is causing the noise. Use Blue thread lock on both of the screws. I would not recommend red thread lock because it will be very hard to remove the screws after.

 

[GrudgE]

Get the manifold with spring mount it allows for things to give and bounce back. The hard mount of the screws means that when taking jumps the weight of the exhaust keeps flexing the pipe. This will not happen with the spring mount.

 

[MotorOil]

try thread lock on the screws

The screws were still very tight and had not loosened on the exhaust manifold. It is the pipe between the muffler and the exhaust manifold that literally broke off from the exhaust manifold itself.

It sounds like your screws which hold the exhaust on are vibrating off, which is causing the noise. Use Blue thread lock on both of the screws. I would not recommend red thread lock because it will be very hard to remove the screws after.

The screws were still very tight and had not loosened on the exhaust manifold. It is the pipe between the muffler and the exhaust manifold that literally broke off from the exhaust manifold itself.

 

[blckrevo33]

can u put up some pics? it might help with a solution.

 

[GrudgE]

I know what he is saying the manifold pipe breaks right at the point where it bolts to the motor. I had this happen to me. This has been a weak point for a while, hence why the platinum models all have spring mounted exhausts. Once again I recommend getting the spring mounted exhaust from your LHS shouldn't be much more then $10. The reason is breaks is the manifold is only made out of thin aluminum and isn't strong enough to support he weight of the exhaust when jumping. With the spring mounted when you jump it allows the entire exhaust system to move and the springs pull it back into place then. Most performance engines use spring mounted exhaust and all of the Platinum do to. I guarantee it will solve your issues.

 

[blckrevo33]

good enough grudge eventhough i have not had this problem i think i am going to take your advise and get rid of mine and get the spring secured one so hopefully i wont come across this prob in the future. thanks for the good advise.

 

[MotorOil]

Get the manifold with spring mount it allows for things to give and bounce back. The hard mount of the screws means that when taking jumps the weight of the exhaust keeps flexing the pipe. This will not happen with the spring mount.

Makes sense. My DuraTrax had a spring mount and never broke. Jumps, heat, vibration, etc. probably weakened the Revo's pipe to the point where it eventually just cracked and the vibration and heat of the engine did the rest -- which is why it usually broke while not even doing any jumps. Also, the pipe on my DuraTrax was steel -- not some kind of brittle cast aluminum/alloy like on the Revo.

What is interesting is that most of the driving was not as much jumping as much as it was playing around with making it spin out, doing 360's, etc. and other tricks along those lines. The jumping was kept pretty conservative, low speed and without much more than 6-8 inches of height most of the time while driving the truck up a small grass embankment in order to make it hop onto the driveway.

And, because each time the pipe broke it was after about the same number of tanks, plain logic would seem to dictate that the breakage can be more attributed to metal fatigue from vibration and heat than from minor jumping (or, more accurately, hopping).

 

[solly69]

seems like a problem with a few people
go with the spring mounted 1 and you shouldn't have a problem

 

[revo_rob_1984]

I know what he is saying the manifold pipe breaks right at the point where it bolts to the motor. I had this happen to me. This has been a weak point for a while, hence why the platinum models all have spring mounted exhausts. Once again I recommend getting the spring mounted exhaust from your LHS shouldn't be much more then $10. The reason is breaks is the manifold is only made out of thin aluminum and isn't strong enough to support he weight of the exhaust when jumping. With the spring mounted when you jump it allows the entire exhaust system to move and the springs pull it back into place then. Most performance engines use spring mounted exhaust and all of the Platinum do to. I guarantee it will solve your issues.

:thumbup::goodpost:

 

[bike]

Mine just broke last night at the same spot. I'm going to try the spring mounted one as well. Great help here!

 

[GrudgE]

Doesn't have to be jumps for it to break, flip it over backwards in a wheelie, landing on the wing or bumper, getting hit in the rear bumper. Figure your exhaust is mounted the the rear body posts any impact there is gonna travel thru the pipe to the weakest point of the system.

 

[tuner14e]

this worked for my problem

i loosened the stem that comes off the muffler itself then put the whole assembly on to the engine then positioned the exaust to the least stressful spot then tightened it up where the flange off the manifold and the flange on the exaust were barrelly apart and lined up perfectly, then tightened up the stem that holds the exaust from moving. this has worked for me for the past month or so.