LO206 Silencer Pipe ??

M

morehorsepower

New member
Can the silencer be welded to the exhaust pipe ? Over the weekend we had many that continue to come lose and 2 that fell off that where safety wired . Also we never had this problem until are tech guy made us cover the pipe as per rule #36 . All the clamps where the aluminum type . After we started seeing the problem we drilled out the bolt hole and ran a through bolt and double nutted some of them . It appears that the aluminum is annealing at this point . Please advise on the best fix at this point .


Thanks Bill !
 
We run IKF rules. They are essentially the same as the Briggs rules with the exception of the exhaust. IKF does not allow the silencer to be welded, pretty sure that is also true with the Briggs rules. IKF does not want the silencer wrapped. This is consistent with all of their other engine exhaust rules. To solve your problem do not use the aluminum clamp. Use a stainless T-bolt clamp. ( example: Jeg's p/n 555-82001 works perfectly )
 
I hate those clamps took them all off and use steel muffler clamps. Double nut both bolts and haven't touched it since, never had a problem since either.
 
Jamie, I don't know that the aluminum clamps are to blame. I have used them for years with no issues at all. Then again, I make sure that they are tight and safety wired properly so that they cannot hit the track. (I'm not sure what issues you've had with them.) The stainless clamps are nice and work well also -- but they still need properly installed and tightened. Jimbo has a good price on them. Keep an eye on the tolerances of the pipe end and muffler flare as well - they are not as consistent as we would like to believe. You can feel when a muffler fits tight, and when it slides right on with little resistance. In my opinion, it should require a bit of tapping together with a deadblow hammer. (some do, some do not)
I understand why Dave/Briggs added to the Briggs rules that the muffler be wrapped, but personally, I think it causes more problems than it's worth. When a guy wraps the muffler and puts a hose clamp or two over it, you can about count on it coming loose and getting caught in the chain - what happens next is anyone's guess.

Having the right pipe bracing is also critical. (maybe the most critical)



--
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cuts
www.CarlsonMotorsports.com
Celebrating 25 years of service to the karting industry
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We all know aluminum expands at a greater rate than steel. On top of that, you also have a steel bolt in the aluminum clamp holding it together. Add the run time on top of that and the multiple expansions and contractions and those aluminum threads at some point just aren't what they were when they were new. I can't recall seeing any headers with the aluminum clamp that didn't show signs of the silencer rotating or "walking" on the pipe. That's the first thing I do when I see one in the shop is toss it in the can.
 
I've only run an aluminium clamp. Always run a lock washer and loctite. Havent had one come loose yet. Make sure the muffler is on tight as said above too.
 
Right on Jamie.
The aluminum also stretches and i often see the two ends of the clamp butt together.
Once that happens you can tighten it as tight as you want and it won't do anything to hold the muffler on.
It's dangerous. Try dogging a muffler at XX miles an hour as you see it coming at you.
 
Anyone know the typical temperature at the muffler clamp? Just curious. We use aluminum connecting rods with steel bolts torqued way less than the 5/16" Allen bolt in a muffler clamp. They go through many heat cycles as well. How much expansion actually is taking place 20-25" away from the port?
Are you all not using a brace to the muffler? Even RLV recommends that.
Not saying you guys are wrong -- just wondering why you're seeing a problem with the aluminum clamps and I am not.

Jim, you say that the aluminum stretches -- don't the hose clamps stretch also? Every one I've used sure has. At least the bolt type hose clamps don't strip the threads like the cheap clamps do. NEVER use the typical cheap hose clamps.
Now, if the two ends of the aluminum clamp butt together as you say, then of course it won't clamp down tight. That should be common knowledge, no different than a wheel hub, gear hub, or brake hub.

Jamie, you guys running the road race and enduro stuff have to make everything bullet-proof to last 30 minutes or more of continuous run time. In 10-15 laps on an oval track, I suspect I'm not seeing the heat and abuse of parts that you are.
 
I've used both the aluminum muffler clamp and the auto stainless clamp and couldn't get them to clamp the muffler to the pipe. Made my own that is simular to a axle locking collar and have had no problems since.
 
Brian C.

My guess would be because the alum clamp application is a lot different than the alum conn rod with steel bolts. ie, the muffler clamp is stretched around the then clamped, so this tyoe of application is very dependent on alum heat stretch, were as the rod application is more rigid for the alum and the rod is stretched to maintain the spring / loading.

Steve
 
I remember running the aluminum ones on the flatheads and have the same problems jimbo and Jamie described. Had a kart in my shop last week that had one on and guy said the muffler kept moving. The clamp jimbo has is ideal otherwise I use two hose clamps to hold it on. I will never run the aluminum again
 
Brian, I have built 2 times as many, maybe 3 times as many oval engines as I have sprint and enduro animals. I see it just as much on the oval engines. It might take a little longer, but sooner or later it happens. I don't know the exact temp of the pipe/silencer, have to check it with a temp gun the next time I run one. With the pipe wrapped, even on a 15-20 lap oval race..... it's HOT. :)
 
Comparison of temps between pipe and rod, run 20 laps spray some engine oil on the pipe, do you suppose that is what happens at the rod, if it is what is happening internally, you only have one more lap, don't worry about your silencer.
 
The temp at the muffler doesn't get hot enough to check on the dyno (not long enough run time under load) so it would have to be checked at the end of an actual race.

Not disputing you guys using a different clamp (the one Jimbo & Jegs sells is a very good one) - just trying to grasp why so many well informed racers are having this problem, yet I have not seen it on our own engines. Before this discussion, I would have just chalked it up to improper installation or user error. If I need to be changing out all of my customers' muffler clamps because they fail, then I need to see one fail that I've installed first. I'm not doing anything different than most of you I would imagine. Proper bracing, good muffler fit, clamp tight, safety wire - all the usual stuff. I do use a hi-temp never seize on the pinch bolt - but that is just to prevent seizing in the aluminum threads. Actually, once the muffler and clamp are installed, I never remove it or even loosen it again.
If the temperature at the muffler is as high as some suggest, and that we are experiencing a drastic difference in thermal expansion at that temperature between the steel & aluminum, enough to make the muffler clamp loosen and muffler fall off, then I'd have to concur that the aluminum clamp is not sufficient (despite my personal experience with them.) I'm certainly not too old to learn.
Now, knock on wood I don't lose a muffler this weekend! :)
 
Not the best photo but you can see that the clamp is double nutted the safety wired is there and there is still a gap in the clamp and the pipe still came loose .



Look real close you can see where the pipe has been mashed a little after the clamp was tighten .

Same here .

Some one is going to get hurt with a flying silencer .
 
Stop using the Aluminum muffler clamps!
The current RLV mufflers now have tabs welded on them to attach safety wire
 
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