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As they say, a picture is worth a thousand words...
For those that have never encountered any problems with the VMG differential/crown gear consider yourself lucky and go read another post
.
I had owned a pair of VMG Can Am's awhile back and did have problems with both the VMG and the replacement Slot.It crown gear stripping after relatively few laps even though I followed the "fixes" to the letter...twice.
I had always thought the real culprit was NOT the differential, but the "flex" of the chassis in the rear because unlike most slot cars there was no "chassis to body" mounting screw(s) to add stiffness. The resulting unchecked flexing allowed for the crown & pinion to become misaligned when the car was run and the end result, in my case, stripping the crown gear.
At that time I was disappointed in them because of the problem and the extra $$$'s I had wasted trying to get them to work that though I knew stiffening the rear end would solve the problem I couldn't see "how".
A little while ago I was reading some reviews and I looked at one on the VMG Can Am cars...when I saw the picture of the bare chassis once again this "fix" came to mind.
Now I have done the "fix" of super gluing everything down as well, but adding those "braces" from the motor to the top of the axle supports most definitely cures the chassis flex of the entire rear end assembly. Now you can use any material you like - I used 1/8" aluminum tubing since it was handy - and I'm sure it will work fine.
As of this writing I have put nearly 1750 laps on the car with the only two hiccups being a loose rear wheel and one of the "braces" becoming unglued from the axle support...I'll be mixing up some epoxy later today to prevent that from happening in the future. Simply said, the car performs as it is supposed to now with no differential/crown gear problems at all.
However, nothing is really ever simple - if you notice "where" the bracing is on the motor, those that have VMG's know that there is a very nicely detailed Chevy engine that sits on the motor...well, a little bit of "surgery" is needed to make it fit again. I have the Lola and a McLaren and although the area that needs cutting away doesn't "show", both have "different", for the lack of better words, motor "toppers". I imagine there might be differences with the other McLaren versions as well as the Mirages and BRMs and the upcoming March & Courage???
In the case of the Lola, I used a razor saw to cut off the sides of the "topper", but leaving the exhaust pipes - for the McLaren (8D) cut the sides up to the cylinder heads. In either case, the removal of these areas can not be seen when the cars are reassembled. To my eye, even cutting away this area still leaves more engine detail than most slot cars...especially since most of it is "hidden".
One other thing, you'll notice that there are 2 thin posts/supports on the inside of the body in the rear...they sit where the axle supports are on the chassis (I guess to add some stiffness when the body is on)...if you put the "braces" where I did then these posts need to be cut down a bit or in my case, just totally removed...and like the motor "toppers", with no ill-effects.
So if you have some VMG's that have been giving you problems, give this a try. I'm very happy with the results with the Lola and when I do the McLaren shortly I will experiment a bit more to see if this can be done without the cutting off of anything...

For those that have never encountered any problems with the VMG differential/crown gear consider yourself lucky and go read another post

I had owned a pair of VMG Can Am's awhile back and did have problems with both the VMG and the replacement Slot.It crown gear stripping after relatively few laps even though I followed the "fixes" to the letter...twice.
I had always thought the real culprit was NOT the differential, but the "flex" of the chassis in the rear because unlike most slot cars there was no "chassis to body" mounting screw(s) to add stiffness. The resulting unchecked flexing allowed for the crown & pinion to become misaligned when the car was run and the end result, in my case, stripping the crown gear.
At that time I was disappointed in them because of the problem and the extra $$$'s I had wasted trying to get them to work that though I knew stiffening the rear end would solve the problem I couldn't see "how".
A little while ago I was reading some reviews and I looked at one on the VMG Can Am cars...when I saw the picture of the bare chassis once again this "fix" came to mind.
Now I have done the "fix" of super gluing everything down as well, but adding those "braces" from the motor to the top of the axle supports most definitely cures the chassis flex of the entire rear end assembly. Now you can use any material you like - I used 1/8" aluminum tubing since it was handy - and I'm sure it will work fine.
As of this writing I have put nearly 1750 laps on the car with the only two hiccups being a loose rear wheel and one of the "braces" becoming unglued from the axle support...I'll be mixing up some epoxy later today to prevent that from happening in the future. Simply said, the car performs as it is supposed to now with no differential/crown gear problems at all.
However, nothing is really ever simple - if you notice "where" the bracing is on the motor, those that have VMG's know that there is a very nicely detailed Chevy engine that sits on the motor...well, a little bit of "surgery" is needed to make it fit again. I have the Lola and a McLaren and although the area that needs cutting away doesn't "show", both have "different", for the lack of better words, motor "toppers". I imagine there might be differences with the other McLaren versions as well as the Mirages and BRMs and the upcoming March & Courage???
In the case of the Lola, I used a razor saw to cut off the sides of the "topper", but leaving the exhaust pipes - for the McLaren (8D) cut the sides up to the cylinder heads. In either case, the removal of these areas can not be seen when the cars are reassembled. To my eye, even cutting away this area still leaves more engine detail than most slot cars...especially since most of it is "hidden".
One other thing, you'll notice that there are 2 thin posts/supports on the inside of the body in the rear...they sit where the axle supports are on the chassis (I guess to add some stiffness when the body is on)...if you put the "braces" where I did then these posts need to be cut down a bit or in my case, just totally removed...and like the motor "toppers", with no ill-effects.
So if you have some VMG's that have been giving you problems, give this a try. I'm very happy with the results with the Lola and when I do the McLaren shortly I will experiment a bit more to see if this can be done without the cutting off of anything...