R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro Off-Road

Reply
 
Thread Tools Search this Thread
Old 08-09-2009, 10:24 PM   #1
Tech Regular
 
builtb16a's Avatar
 
Join Date: Jun 2009
Location: Redlands, CA
Posts: 295
Trader Rating: 1 (100%+)
Default 2nd cracked case.. engine mount problem. any suggestions?

long story short. bought a new axial .28 spec 1 for my XTM 1/8 truggy..

2nd day, cracked the case.

sent back to axial. repaired under warranty. filed the back side of the mounts.. and today 2nd case broken.

so i got home, took some high deff photo's, and come to RCTECH for advice.

can i use different mounts? i can show you the plates on the truck chassis if you need to see.. they're slotted so you can slide adjust it to the spur.











1st case was free.. i dont' know if i should even ask on this 2nd case. might end up being a parts motor since a case from axial is almost the price of the engine fron amain.
builtb16a is offline   Reply With Quote
Old 08-09-2009, 10:42 PM   #2
Tech Regular
 
builtb16a's Avatar
 
Join Date: Jun 2009
Location: Redlands, CA
Posts: 295
Trader Rating: 1 (100%+)
Default

and to explain what i believe to be my issue.

you can't really tell by the 2 cases side by side.. but i think the XTM 24.7 case has longer ears, and the holes are out further than the axial.

so wehn the mount sits on the ears.. the holes are further out on the XTM, and closer on the axial.. so wehn i tighten them down they right away want to stretch the ears off the axial case.

the only other solution has to be mounts. i can't see shaving down those mounts to fit, without loosing strength in the mount. the sliders give me great adjustment, but if i had solid tapped mounts, i think they would be alot stronger, and thinner.
builtb16a is offline   Reply With Quote
Old 08-10-2009, 10:08 AM   #3
Tech Regular
 
builtb16a's Avatar
 
Join Date: Jun 2009
Location: Redlands, CA
Posts: 295
Trader Rating: 1 (100%+)
Default

43 views... not 1 comment.
builtb16a is offline   Reply With Quote
Old 08-10-2009, 10:19 AM   #4
Tech Addict
 
Join Date: Apr 2009
Location: Hayward CA
Posts: 702
Trader Rating: 32 (100%+)
Default

My best advice is get a 1 piece engine mount if there is one. or make one.

but where is it cracking ? is the crack line vertical? or horizontal relative to the engine?
__________________
Z01B | Xerun 150A 2000kv | Hitec | Desire-power 6S LiPo
Z01T | Tekin RX8 1700kv | Hitec | Desire-power 6S LiPo
Support your LHS, Al's Hobby, Elmhurst
devilchrist is offline   Reply With Quote
Old 08-10-2009, 10:20 AM   #5
Tech Master
 
sideways88's Avatar
 
Join Date: Apr 2007
Posts: 1,097
Trader Rating: 34 (100%+)
Default

is your clutch bell hitting the chassis. if so that could be why your braking the cases. i had the same problem on my sh zcar buggy. i broke 2 motors on that thing cause of it.
__________________
;)
sideways88 is offline   Reply With Quote
Old 08-10-2009, 10:22 AM   #6
Tech Regular
 
builtb16a's Avatar
 
Join Date: Jun 2009
Location: Redlands, CA
Posts: 295
Trader Rating: 1 (100%+)
Default

1st case cracked along the case mount.. right along the ear.. straight down.

2nd case cracked the ear completely off.

i bashed the stock XTM motor around for months, taking some narley hits, and never had a problem. it has to be these mounts. and its starting to be an expensive learning curve.
builtb16a is offline   Reply With Quote
Old 08-10-2009, 10:32 AM   #7
Tech Regular
 
builtb16a's Avatar
 
Join Date: Jun 2009
Location: Redlands, CA
Posts: 295
Trader Rating: 1 (100%+)
Default

Quote:
Originally Posted by sideways88 View Post
is your clutch bell hitting the chassis. if so that could be why your braking the cases.
clutch bell is not hitting. with my motor plates, and mounts, its quite high. my pull start is clear also, so there's no contact with the chassis.

i don't have a flex bracket, or anything to prevent the chassis from flexing, but the whole outside of the chassis has a rolled lip, and has braces from the front and rear diff cases to about 5/8th's into the middle from each side. i don't think im having a chassis flex problem, it has to be these mounts. those holes lining up concerns me.



1st motor.. 2nd motor is the same thing, just completely broke off.
builtb16a is offline   Reply With Quote
Old 08-10-2009, 10:36 AM   #8
Tech Addict
 
Join Date: Apr 2009
Location: Hayward CA
Posts: 702
Trader Rating: 32 (100%+)
Default

I suggest going back to stock mounts.
__________________
Z01B | Xerun 150A 2000kv | Hitec | Desire-power 6S LiPo
Z01T | Tekin RX8 1700kv | Hitec | Desire-power 6S LiPo
Support your LHS, Al's Hobby, Elmhurst
devilchrist is offline   Reply With Quote
Old 08-10-2009, 10:39 AM   #9
Tech Regular
 
builtb16a's Avatar
 
Join Date: Jun 2009
Location: Redlands, CA
Posts: 295
Trader Rating: 1 (100%+)
Default

lol. these are stock mounts. well.. stock was silver. these are blue. same exact mount. ive broke 2 motors on the stock mounts. not looking good.
builtb16a is offline   Reply With Quote
Old 08-10-2009, 10:43 AM   #10
Tech Addict
 
mauromj's Avatar
 
Join Date: May 2007
Location: Spokane Wa
Posts: 571
Trader Rating: 20 (100%+)
Default

Something has to be hitting then when you tighten it down, it puts alot of stress on it untill it breaks..
mauromj is offline   Reply With Quote
Old 08-10-2009, 10:48 AM   #11
Tech Regular
 
builtb16a's Avatar
 
Join Date: Jun 2009
Location: Redlands, CA
Posts: 295
Trader Rating: 1 (100%+)
Default

well, like i said in the 1st post.

it looks like the ears on the stock case, are longer, or the holes for the mount are further out. cuz when i line up the mounts on each motor its more outward on the stock motor and really tight on the new motor. so, when i tighen the bolts down, it already puts stress on the mounting ears.

my LHS says i have to use these mounts, because i have to adjust the front to back engine placement of the clutch bell on the spur.. but solid mounts would be much stronger, and could hopefully be thinner also.

look at those motor pics.
builtb16a is offline   Reply With Quote
Old 08-10-2009, 10:57 AM   #12
Tech Master
 
ABN Hoosier's Avatar
R/C Tech Elite Subscriber
 
Join Date: Nov 2008
Location: El Paso, Texas
Posts: 1,004
Trader Rating: 20 (100%+)
Default

Here is my 2 cents, I think that the engine cases from axial are substandard. You get what you pay for though. Those engines are cheap and run for a while very strong, but like I said, you get what you pay for. Here are some pics from my experience with Axial Mils back in the day.



ABN Hoosier is offline   Reply With Quote
Old 08-10-2009, 11:09 AM   #13
Tech Fanatic
 
Join Date: Jul 2008
Posts: 855
Default

If the mount is pushing on the side of the engine after the scews are tighten putting stress on the mount. Try adding shim between the engine and mount make sure the two are not touching. After that if it still breaks I say the engine is subpar
pdmustgt is offline   Reply With Quote
Old 08-10-2009, 12:27 PM   #14
Tech Master
 
2fst2c's Avatar
 
Join Date: Oct 2008
Location: Martin, MI
Posts: 1,939
Trader Rating: 114 (100%+)
Default

I know on my MP9 I had to grind out some more of the engine area on the chassis because the back plate would hit the chassis with some motors and would have caused the same problem if I hadn't noticed it. Is there enough clearance in that area under your pull start and back plate?
2fst2c is offline   Reply With Quote
Old 08-10-2009, 01:51 PM   #15
Tech Regular
 
builtb16a's Avatar
 
Join Date: Jun 2009
Location: Redlands, CA
Posts: 295
Trader Rating: 1 (100%+)
Default

there is plenty of room.. but the guy that posted his ears breaking off.. same as mine, same mounts... same stress. so it has to be in the mounts, not the substandard cast aluminum they're making these cases out of.

ok.. now round 2. i picked up some RC8 mounts. although the mount to the engine fits GREAT! even alittle room in the back, now my mount to chassis holes are wrong.

gezz.. i don't know what to do. its almost like i need to use the universals.. or a new truck. this is rediculous.

builtb16a is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 01:58 PM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net