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JRX-T mid motor conversion
Posted: Tue May 03, 2016 7:08 am
by aconsola
I started with this rusty jrx-T via ebay
and one of these aluminum mid motor conversion shock towers
After cleaning ip the car I got this. Trans turned around and shock tower mounted up. Holes drilled with a #43 drill for the 4-40 screws to tap threads into the plastic trans case
I shaved off the diff access stub and drilled a hole on the other side to adjust the diff, also drilled through the solid bearing carrier side for top shaft to exit on the right
I used a second chassis plate turned around and screwed together as a template to drill the 2 extra mount holes for the rear bulkhead
All mounted up, however with the bulkhead in the back and the hinge pin carrier in the front it now has toe-out as the carrier mounting points are wider spaced than the bulkhead. Need to trim the motor plate as the motor will mount from the opposite side
The solution to the toe-out problem is to cut a rear bulkhead, in this case one that had the upper mount ear broken off already so I didn't mind cutting it up so much. this keeps the inner hinge pins parallel. Motor plate trimmed, I kept a small tab on the bottom and drilled through to use the bulkhead mounting hole as an extra attachment point
All mounted up with a 5-link rear. I used the .050 shorter toe in links to regain the toe I lost by using the bulkhead parts on both ends of the inner pins. I'm awaiting a shorty lipo I ordered, will figure out battery and electronics placement next.
Re: JRX-T mid motor conversion
Posted: Tue May 03, 2016 8:11 am
by matt1ptkn
That's awesome! I'll be interested to hear how it drives.
Re: JRX-T mid motor conversion
Posted: Tue May 03, 2016 12:32 pm
by Lavigna
Very cool build. Can't wait to see the end product.
Re: JRX-T mid motor conversion
Posted: Tue May 03, 2016 12:59 pm
by Coelacanth
I'm liking it. It's a bit of effort and design challenge to convert a RWD rear-motor to mid-motor, but when you're done, you have something cool & unique.

Re: JRX-T mid motor conversion
Posted: Tue May 03, 2016 1:41 pm
by Mr. ED
When I did this bitd, I cut the lower section of the bulkhead and put that on the front. The original front part I moved under the bulkhead replacing the removed part. Toe- in and slight upward angle perfectly restored, and all it took was a bit of swaing and 2 longerscrews to keep the modified bulkhead to the chassis.
Re: JRX-T mid motor conversion
Posted: Fri May 06, 2016 2:01 am
by knixdad
It looks nicely done so far, but if you put a Cab Forward Body on it, then things may go south.
Re: JRX-T mid motor conversion
Posted: Fri May 06, 2016 2:11 am
by GoMachV
Mr. ED wrote:When I did this bitd, I cut the lower section of the bulkhead and put that on the front. The original front part I moved under the bulkhead replacing the removed part. Toe- in and slight upward angle perfectly restored, and all it took was a bit of swaing and 2 longerscrews to keep the modified bulkhead to the chassis.
That's pretty much what I did on the ultima I made mid motor as well. Worked great to keep toe and anti squat proper
Re: JRX-T mid motor conversion
Posted: Fri May 06, 2016 3:02 am
by Mr. ED
GoMachV wrote:
That's pretty much what I did on the ultima I made mid motor as well. Worked great to keep toe and anti squat proper
Really? I tried this on an ultima also
It didn't work for me though with the standard gearbox. The motor sat too close and too low to clear the plastic part. It worked with the stealth I tried later.
Re: JRX-T mid motor conversion
Posted: Fri May 06, 2016 6:50 am
by GoMachV
Mine had a track master direct drive

Re: JRX-T mid motor conversion
Posted: Mon May 09, 2016 11:01 am
by RCveteran
Where or who is that shock tower from?
Re: JRX-T mid motor conversion
Posted: Wed May 11, 2016 8:41 am
by aconsola
I don't actually know the original maker for the vintage part.
There is a facebook group, old school RC, where a member reproduced these.
He is on here too, but does not have a vendor section, durb69
in the second pic in first post, original has round holes, new version with squares