da Rock

So the last couple of Slimline pitts mufflers I've gotten have gotten loose in flight. It's not unusual for the first couple of heat cycles to show up inadequately tightened mufflers, is it.

However, both of these wound up causing the nightmare many of us fear. When I got them home to tighten them, I stripped the bolts, and it was way before the heavy hand got into the act. It turns out the bolts were the metric size a step smaller than 8-32s. And they both felt wobbly when I pulled them to clean off the threads. (I like to wash away the oil and gunk when installing mufflers... and reinstalling.)

So when I got everything clean and dry, the first round of tightening resulted in the first bolt tight stripping.

I wonder...

The solution was simply to thread the manifold to 8-32 and swap in the right length bolts. While doing that, I noticed the metrics were more than 1/8" longer than necessary. I wonder....

Anyway, I figured I'd put this out sorta for you guys that like to pre-empt things like this. Both mufflers were new designs from Slimline and both have significantly more mass in the suspended part. One is the 'wrap around' for the OS91 and has considerable weight hanging out. The other is the new Qzone and has half again more mass than the older version 'standard pitts'.

I wonder if they really shouldn't have been mfg'd with 8-32's to begin with. I also wonder why Slimlines aren't around now. Tower seems to have dropped them.

Iflyglow

My Feedback: (79)

I also ordered a wrap around muffler from them, but i ordered it directly. I have a feeling there is reason why hardlynobody carries there stuff anymore. My muffler arrived two months after the advertised in stock muffler "owner stared on the he 70+ in stock when I ordered it. It was only after I threatened a fraud case with the credit card company did it ship. The sad thing is the rear threaded hole is tapped so poorly I will not use it. I am now deciding if I should run screws all the way through with nuts and washers, or helicoil the holes. On top of the poorly constructed muffler, I was told so much bs by the owner I will never touch there products again period. I was promised a full credit which never arrived. Even after several calls I was told it was in process. He also promised to send there fueling system for there major screw up, that arrived without orings. More phone calls and two weeks later they arrived. I still have not received the credit I was promised. Buyer beware if trying to obtain there products.