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Schumacher Mi4

Old 03-20-2012, 12:39 PM
  #3421  
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martin,

i tried to shim up the steering with the long posts, but the bulkhead was in the way. did you remove that part of the bulkhead to make the 2 tall posts fit? i used 3 mm tall shims on each side instead, and flipped the steering assembly over like you described. Also, is the Corrally motor good for non-boosted 17.5 stock racing? if it is, and if it is ROAR approved, it my be something i want to use at the REEDY Race this year.

thank you,

rich
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Old 03-20-2012, 08:55 PM
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i built the ball diff and followed the manual and Chris Grainger's video to tighten it until the cone washer flatten.

Now, the diff feels like there are notches when I turn them. Did I damaged the diff by over tighten it until the balls notched the plates?

Should I rebuilt with new plates?

I loosen the diff and the 'notch' feeling goes away... its there only when the diff is quite tight.
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Old 03-20-2012, 09:12 PM
  #3423  
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Originally Posted by doriftu View Post
i built the ball diff and followed the manual and Chris Grainger's video to tighten it until the cone washer flatten.

Now, the diff feels like there are notches when I turn them. Did I damaged the diff by over tighten it until the balls notched the plates?

Should I rebuilt with new plates?

I loosen the diff and the 'notch' feeling goes away... its there only when the diff is quite tight.
Diff should not be overtightened...ever...
you should be able to re-use...might need to rebuild and examine...

Did you sand/polish the plates (with very fine grit sand paper). this will make a huge difference for the quality of the diff.
once together...build up then install in car..
put car on a stand...and hold one wheel and break the diff in..a few minutes each side..this should help the diff ball seat into the plate...should score the plate slightly.
Run the car under load...then recheck diff.
With the Schumacher diffs ..make sure to install the set/locking screw correctly.

should last for quite a while after that.
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Old 03-20-2012, 09:20 PM
  #3424  
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You only want the diff as tight as it needs to be to avoid slipping. I'm definitely not a ball diff expert, and will probably never go back to one since I have gear diffs now.

The suggestion I got from a fellow/former Schui driver who is handy with the wrenches, was to tighten it slowly, and check for slip gently(!) as you tighten it, and only tighten it until it stops slipping.

The only good ball diff I've ever had is the one that came in a used Mi4 I bought. It was extremely free with zero slip for about a year until it started getting crunchy. I've never been able to build one that well. That's why I jumped on the gear diffs and never looked back.

-Mike

EDIT: Josh Cyrul made an interesting post on diff building in the CEFX 2011 thread within the last few weeks. I think it was in relation to 1/12 scale, but a good diff is even more important there, so I'd think it could apply to TC's as well. I don't remember the particulars, but I do remember it seemed pretty backwards from most advice I've heard, involving intentionally scoring the rings.

EDIT2: This post: http://www.rctech.net/forum/10332547-post504.html

Last edited by grippgoat; 03-20-2012 at 09:33 PM.
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Old 03-20-2012, 09:44 PM
  #3425  
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Originally Posted by grippgoat View Post
= I don't remember the particulars, but I do remember it seemed pretty backwards from most advice I've heard, involving intentionally scoring the rings.

EDIT2: This post: http://www.rctech.net/forum/10332547-post504.html
I actually like to see the scoring in the diff ring...
once the diff balls aligned correctly it will make the smoother and last longer.

I have been trying two cars 1 with a gear diff
other with a diff.
the Diff actual feels the most neutral...the gear diff can get a little aggressive.
but I have been utilizing the Gear diff at this point due to ease of maintenance.
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Old 03-21-2012, 05:21 AM
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Originally Posted by olhipster1 View Post
Diff should not be overtightened...ever...
you should be able to re-use...might need to rebuild and examine...

Did you sand/polish the plates (with very fine grit sand paper). this will make a huge difference for the quality of the diff.
once together...build up then install in car..
put car on a stand...and hold one wheel and break the diff in..a few minutes each side..this should help the diff ball seat into the plate...should score the plate slightly.
Run the car under load...then recheck diff.
With the Schumacher diffs ..make sure to install the set/locking screw correctly.

should last for quite a while after that.
Thanks... look like I need to get a new sets of diff plate and rebuilt the diff!

Is there diff covers to 'seal' the diff to prevent dirt? I run in quite dusty tracks...

Im new to Schumacher cars...
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Old 03-21-2012, 08:42 AM
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Originally Posted by doriftu View Post
Thanks... look like I need to get a new sets of diff plate and rebuilt the diff!

Is there diff covers to 'seal' the diff to prevent dirt? I run in quite dusty tracks...

Im new to Schumacher cars...
If you can get the gear diff.
The Schumacher gear diff is made by Spec R, the bonus is that the
gear diff comes with upgrade carbon gears...very nice fit....mine has been leak proof since day one...just follow the build guide.
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Old 03-22-2012, 11:25 AM
  #3428  
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Originally Posted by gdcopbdcop View Post
martin,

i tried to shim up the steering with the long posts, but the bulkhead was in the way. did you remove that part of the bulkhead to make the 2 tall posts fit? i used 3 mm tall shims on each side instead, and flipped the steering assembly over like you described. Also, is the Corrally motor good for non-boosted 17.5 stock racing? if it is, and if it is ROAR approved, it my be something i want to use at the REEDY Race this year.

thank you,

rich
if you want to mount the steering on posts instead of on the bulkhead you obviously need to get rid of the bulkhead bits the plate mounts to as per kit.

the corally motor will never on earth be roar legal. Roar and Efra have similar rotor rules as far as I know and the corally motor breaks every one of them :-)
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Old 03-22-2012, 03:48 PM
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Originally Posted by Martin Hofer View Post
if you want to mount the steering on posts instead of on the bulkhead you obviously need to get rid of the bulkhead bits the plate mounts to as per kit.

the corally motor will never on earth be roar legal. Roar and Efra have similar rotor rules as far as I know and the corally motor breaks every one of them :-)
martin,

thank you for the quick response
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Old 03-22-2012, 08:16 PM
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Originally Posted by doriftu View Post
i built the ball diff and followed the manual and Chris Grainger's video to tighten it until the cone washer flatten.

Now, the diff feels like there are notches when I turn them. Did I damaged the diff by over tighten it until the balls notched the plates?

Should I rebuilt with new plates?

I loosen the diff and the 'notch' feeling goes away... its there only when the diff is quite tight.
Was it the first time you put the diff together, if so check under the head of the bolt, I had one that had a small lump of steel on the radius this caused the diff to feel really bad.

Regards
Gary
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Old 03-22-2012, 09:14 PM
  #3431  
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What is the difference between the mi4cx, mi4cxpro and mi4cxl. I can get the mi4cxpro for what seems to be a pretty god deal. I race outdoor asphalt usually short smallish tight track that is pretty loose ( rear traction at a prime)
Thanks
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Old 03-22-2012, 09:53 PM
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Originally Posted by rdlkgliders View Post
What is the difference between the mi4cx, mi4cxpro and mi4cxl. I can get the mi4cxpro for what seems to be a pretty god deal. I race outdoor asphalt usually short smallish tight track that is pretty loose ( rear traction at a prime)
Thanks

the MI-4CXL has a long top deck, and the short weave chassis. it also has different bulkheads, steering rack, and sway bar mounts.

all together, it adds up to way more steering, and more rear traction than you can even imagine. this adds up to more corner speed.

it is well worth the extra cost........
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Old 03-23-2012, 04:34 AM
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Originally Posted by gdcopbdcop View Post
the MI-4CXL has a long top deck, and the short weave chassis. it also has different bulkheads, steering rack, and sway bar mounts.

all together, it adds up to way more steering, and more rear traction than you can even imagine. this adds up to more corner speed.

it is well worth the extra cost........

Thx
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Old 03-23-2012, 08:57 AM
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Do the CVDs need anti wear grease?

Btw, the pins for the wheel hex in Step 20 are missing in my kit! both of them... sighhh...
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Old 03-23-2012, 09:42 AM
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Originally Posted by doriftu View Post
Do the CVDs need anti wear grease?

Btw, the pins for the wheel hex in Step 20 are missing in my kit! both of them... sighhh...
CVDs always need grease....that goes for all brand cars.
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