OFNA Titan Brushless Conversion

[dure16]

I picked up this awesome OFNA Titan to rebuild for the kiddos. Thanks @trunkmonkey1

It's in good shape overall and shouldn't require much work. The only visible problem is a cracked knuckle but it looks like they're available on eBay (surprisingly).

This will be a simple build if all goes according to plan:

• No permanent modifications since it is a classic
• Low power brushless to protect the drivetrain and prevent damaging crashes
• Tune the 2-speed transmission to always stay in 1st gear
• Get the manual brakes working (yeah baby)
• Find a body that doesn't look terrible
• Low effort instead of full rebuild
• Spare parts instead of spending money

I'll post more pics as it comes together!

 

[WoodiE]

Can't wait to see this come together. I've always been a fan of many of the OFNA models.

 

[dure16]

Figuring out a way to mount the motor was the first challenge. It's a tight fit to reach the 1st gear spur without having to use a huge pinion. The existing chassis screw hole locations weren't ideal for secure mounting, but with the goal of no permanent modifications, I decided to give it a shot.

This is a lazy build so I did a lot of eyeball measurements instead of taking things apart. That meant multiple iterations and printed prototypes to get it right, but the end result turned out great. The mount isn't pretty but it is sturdy. I designed it in Fusion360 and printed it in polycarbonate plastic.

 

[Radiocontrolsoul]

I’ll definitely be following this build. I had wanted to do this when it popped up on here. Had a titan way back when and always kicked myself for selling it. Cool stuff man

 

[dure16]

Next up is the battery tray. The brake servo also needs support after I removed the factory battery/receiver box.

Again, my goal was no permanent modifications, so I found some chassis holes to use and got to measuring and prototyping. I designed the tray for a standard hardcase 3S battery with a velcro passthrough underneath. I also decided to combine the battery tray and servo support into one piece.

Then I gorilla taped the ESC and receiver, and plugged everything in. I've never used manual brakes so I thought they'd be complicated, but it was actually pretty simple. I adjusted the brake servo connector and springs, and then I set up the aux/brake mix on my transmitter. Easy peasy.

I turned it all on and, to my surprise, everything worked!. This thing scoots pretty good and the brakes are perfect after a little more tuning. The 20 year old hitec and airtronics servos still work fine and there are no perceptible issues with the drivetrain.

I still have to reglue the tires, replace the cracked knuckle, and figure out a body. More to come.

 

[dure16]

Onto the broken knuckle. It's available on eBay, surprisingly, but I'd rather not spend the $30 for a replacement.

I'm not sure if a zip tie and CA glue will hold up, but I guess we'll find out.

I ran into an unfortunate surprise when working near the front end. The upper arm holder is broken. I can't believe I missed that before.

I looked up the part number and the google machine came up with nada. So it's time to design and print again. I used nylon plastic which should hold up very well.

 

[LibertyMKiii]

Very nice work so far.
I would highly recommend putting some sort of support under the rear of the motor.

Should you want to go with a metal motor mount at some point Saga Custom RC has some good options for universal motor mounts.

 

[dure16]

Very nice work so far.
I would highly recommend putting some sort of support under the rear of the motor.

Should you want to go with a metal motor mount at some point Saga Custom RC has some good options for universal motor mounts.

Thanks. I initially planned to support the motor but that thing is sturdy as hell. I can’t move the end of the motor any more than I can in my Arrma 6S cars.

I didn’t know Saga made universal motor mounts. I just looked them up and that’s definitely the route I’ll go if this plastic one fails. I appreciate the advice.

 

[dure16]

Tires are glued! They seem to be high quality rubber and still feel great after all these years.

 

[dure16]

I found an old SCT body that should work well enough. It's a little wide for a monster truck body, but the length is okay.

It actually looks pretty good after lining it up and making new body post holes. The stock body posts were super long so I made new ones.

The truck was finally done so I made the obvious choice and went straight to a skate park. It jumped great and scooted along better than expected. 33mph on pavement and 29mph on grass. ESC (BLX100) and motor (Surpass 3670) temps were fine and the motor mount held mesh perfectly. The transmission stayed in 1st gear, like I wanted, and the brakes worked well. Mechanical brakes definitely have a better feel than motor brakes.

This was my first time really driving a high CG monster truck and I have to say that I totally get it now. It's different from anything else I've driven and the suspension on this OFNA seems dialed in. It's finally ready for the kids and I may have to buy an LMT to drive with them. Thanks again for the truck @trunkmonkey1

 

[dure16]

I've always been a fan of many of the OFNA models.

I just came across this beauty and figured I’d share:

https://www.facebook.com/share/yJavcQL8K9uraJjv/?mibextid=rVNFAq