Questions and Answers If you have general RC questions or answers discuss it here.

magnum 4 stroke muffler loose

Reply

Old 07-26-2010, 06:30 PM
  #1  
edmoor
Senior Member
Thread Starter
My Feedback: (1)
 
edmoor's Avatar
 
Join Date: May 2009
Location: killbuck, OH
Posts: 241
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default magnum 4 stroke muffler loose

cant keep the muffler tight.....only has a single thread into the head....with a jam nut. i tried high temp. thread locker....still comes loose. cant hardly attatch a strap to the firewall as its fiberglass....and will get too hot. my option im considering is to make a strap and attach it to the engine. anyone else have a better solution for this loose muffler problem?
edmoor is offline  
Reply With Quote
Old 07-26-2010, 06:57 PM
  #2  
jay2000dakota
Senior Member
 
Join Date: Feb 2008
Location: kingsville, ON, CANADA
Posts: 159
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

try high temp RTV silicone on the threads or a muffler system from Macs Products
jay2000dakota is offline  
Reply With Quote
Old 07-26-2010, 07:24 PM
  #3  
red head
 
Join Date: Feb 2005
Location: Zephyrhills, FL
Posts: 2,091
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Get longer bolts !!!! ENJOY !!! RED
red head is offline  
Reply With Quote
Old 07-26-2010, 07:24 PM
  #4  
AviationNut
Senior Member
 
Join Date: Jun 2007
Location: Chatsworth, CA
Posts: 325
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Try tightening the nut when the engine is hot.
AviationNut is offline  
Reply With Quote
Old 07-26-2010, 07:32 PM
  #5  
edmoor
Senior Member
Thread Starter
My Feedback: (1)
 
edmoor's Avatar
 
Join Date: May 2009
Location: killbuck, OH
Posts: 241
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

you dont understand......there are no bolts.......just a pipe with a jam nut. im searching for red rtv ht silicone......cant find it at hobby stores......will check tomorrow at parts stores. in my opinion.....this is a bad design on this muffler setup to begin with, it can only come loose afew times.....and what few threads are in the head will gone......as the pipe is steel.....and the head is mag. or aluminum. i wont buy another engine that dont have a bolt on manifold rest cast into the head. the one pipe method is simple.....but just dont hold up.
edmoor is offline  
Reply With Quote
Old 07-26-2010, 07:33 PM
  #6  
oldvet70
My Feedback: (10)
 
oldvet70's Avatar
 
Join Date: Sep 2004
Location: Grants Pass, OR
Posts: 694
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

If the pipe is only 1 thread in the head it will never stay tight. It must be threaded in much farther than that, at least a 1/4 inch or it's just going to continue to vibrate loose. The design is sound you just need to screw it in farther.
oldvet70 is offline  
Reply With Quote
Old 07-26-2010, 09:50 PM
  #7  
jay2000dakota
Senior Member
 
Join Date: Feb 2008
Location: kingsville, ON, CANADA
Posts: 159
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

The RTV Silicone is made By Permatex for cars. Any auto parts store should have it.
jay2000dakota is offline  
Reply With Quote
Old 07-27-2010, 12:17 AM
  #8  
Charlie P.
 
Charlie P.'s Avatar
 
Join Date: Feb 2003
Location: Port Crane, NY
Posts: 5,088
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Third vote for the silicone gasket. Otherwise they just loosen up over a few flights.
Charlie P. is offline  
Reply With Quote
Old 07-27-2010, 12:49 AM
  #9  
Conrod
 
Join Date: Jan 2003
Location: Palmerston North, NEW ZEALAND
Posts: 245
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Hi
3 to 4 turns of PTF tape ( white plumbers thread tape) screw the header or muffler up then tighten the lock nut. I use it at the cylinder head thread and muffler to header thread. Works on my OS, magnum and YS four strokes.
Geoff
Conrod is offline  
Reply With Quote
Old 07-27-2010, 04:26 AM
  #10  
Steve Percifield
My Feedback: (14)
 
Steve Percifield's Avatar
 
Join Date: Feb 2002
Location: Noblesville, IN
Posts: 1,502
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Screw the jam nut back up the header to expose more threads. Then Screw the header into the engine head using the Teflon tape. Screw it in as far as it can go, then tighten the jam nut.
Steve Percifield is offline  
Reply With Quote
Old 07-27-2010, 06:15 AM
  #11  
Rudolph Hart
 
Rudolph Hart's Avatar
 
Join Date: Apr 2008
Location: Perth, AUSTRALIA
Posts: 4,287
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Short thread it's mostly to do with how you support the muffler
Rudolph Hart is offline  
Reply With Quote
Old 07-27-2010, 03:02 PM
  #12  
carrellh
Senior Member
 
carrellh's Avatar
 
Join Date: Mar 2003
Location: Garland, TX
Posts: 6,544
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Every four stroke engine I have seen has a screw in header like the Magnum and they can be a pain.

Be sure to screw the jam nuts onto the header pipe as far as possible, as in the picture. Screw the header into the engine until it stops and then back it out only enough to point where you want it. Using high temp permatex rtv or teflon thread tape is a good idea. Tighten the jam nut as tight as you can. Get the engine hot, shut it off, and tighten the jam nut again. That should help it stay tight.

Carrell
Attached Thumbnails Click image for larger version

Name:	Qo39185.jpg
Views:	7
Size:	101.1 KB
ID:	1474256  
carrellh is offline  
Reply With Quote
Old 07-27-2010, 05:14 PM
  #13  
shiver
Member
 
Join Date: Feb 2009
Location: Ireland, IRELAND
Posts: 33
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Mine sheared off in flight today[]
shiver is offline  
Reply With Quote
Old 07-27-2010, 08:47 PM
  #14  
MikeL
Senior Member
My Feedback: (3)
 
Join Date: Mar 2002
Location: Bloomington, MN
Posts: 3,282
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose


ORIGINAL: Conrod

Hi
3 to 4 turns of PTF tape ( white plumbers thread tape) screw the header or muffler up then tighten the lock nut. I use it at the cylinder head thread and muffler to header thread. Works on my OS, magnum and YS four strokes.
Geoff
This is the solution. It's also known as teflon tape. Works like a charm, without any fuss. No need to torque things so tight that you damage them, either.

MikeL is offline  
Reply With Quote
Old 07-28-2010, 05:03 PM
  #15  
daveopam
My Feedback: (9)
 
daveopam's Avatar
 
Join Date: Oct 2002
Location: ELK CITY, OK
Posts: 7,464
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

I also use the Teflon tape. It does not lock anything down, but instead takes the minute bit of play out of the threads and keeps the muffler from wiggling loose.

David
daveopam is offline  
Reply With Quote
Old 07-28-2010, 05:59 PM
  #16  
Tarasdad
Senior Member
 
Tarasdad's Avatar
 
Join Date: Aug 2009
Location: California City, CA
Posts: 545
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Never had that problem with my Saito .80. Muffler never even loosened up in flight and I made sure to check it before and after each flight. Still has the original muffler, although I did replace the header with a new one. Didn't need to, the original was still fine, just didn't look pretty any more. Once I have my Aeromaster built and my Saito in it I'll be checking it every flight again.
Tarasdad is offline  
Reply With Quote
Old 07-29-2010, 06:37 AM
  #17  
bps
My Feedback: (3)
 
bps's Avatar
 
Join Date: Oct 2002
Location: Indianapolis, IN
Posts: 1,342
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

Seems when I tighten my muffler when the motor is hot it stays.
bps is offline  
Reply With Quote
Old 07-31-2010, 09:17 AM
  #18  
geeter
My Feedback: (110)
 
Join Date: Apr 2005
Location: newtowne sq., PA
Posts: 675
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: magnum 4 stroke muffler loose

use J-B weld on the threads going into the engine. let it set overnite............works for me on my saito 100................RON
geeter is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service