Installing vx-18

[infernoprime]

I went to try to install the engine only to find this out. And man, am I fuming.

 

[tudordewolf]

I went to try to install the engine only to find this out. And man, am I fuming.

View attachment 180795

Ah bummer, that's a challenge with matching engine compatibility. The VX-18 has a threaded shaft, while your vehicle was made for an "SG/OS shaft," where the flywheel sits directly against the engine, without that 6.5mm spacer.

I think you'd be best off getting the cheapest compatible engine you can, like an FC-18 for example.

 

[Chubaka]

Shorter crank or modify the motor mount. How is spacing behind the motor?

 

[Grizz03]

Can you pull that aluminum spacer off and mount the flywheel and collet closer?
Or what's behind the clutch bell, can that be moved closer in?

 

[tudordewolf]

Can you pull that aluminum spacer off and mount the flywheel and collet closer?
Or what's behind the clutch bell, can that be moved closer in?

That spacer is also the drive washer, it pinches the flywheel as if it's driving a propeller. They would need a brass cone and the press-fit style of flywheel to replace it, as well as cutting short the end of the crank.

It can be done, people used to do that to adapt threaded-shaft engines which is why SG-shaft was innovated in the first place.

 

[Grizz03]

That spacer is also the drive washer, it pinches the flywheel as if it's driving a propeller. They would need a brass cone and the press-fit style of flywheel to replace it, as well as cutting short the end of the crank.

It can be done, people used to do that to adapt threaded-shaft engines which is why SG-shaft was innovated in the first place.

Like the brass collet and flywheel on a traxxas for instance. I did the same on an old Aquacraft engine.

I was only thinking if the original engine didn't require that spacer shouldn't it already be a collet and taper fit flywheel?

 

[infernoprime]

Alright, so it looks like some parts of the old motor are interchangeable. Once I took off the extension that attaches to the motor shaft and echanged it with the old one, the engine fit like a glove.

 

[Grizz03]

Alright, so it looks like some parts of the old motor are interchangeable. Once I took off the extension that attaches to the motor shaft and echanged it with the old one, the engine fit like a glove.

I thought that's how it would work. Glad you got it sorted out and installed.

 

[infernoprime]

I thought that's how it would work. Glad you got it sorted out and installed.

Well, I might have run into problems. I will need a few days to sort things out.

 

[infernoprime]

For a little more clarity, I took some more pictures to explain things more.

Here are the shaft sizes.

Engine shaft size difference

Original engine shaft size

Other parts pictures

Has anyone ever had to grind down an engine shaft to fit before?

 

[Grizz03]

I've used a Dremel with a cutoff blade to shorten.

 

[infernoprime]

Could I use a Grind Stone from a drill bit?

 

[Grizz03]

I don't see why it wouldn't work.
A little trick to help save you from possible aggravation from deformed threads where you ground the shaft down is to put on a nut. It will help clean up the threads making it easier to install the clutch shaft back on. You would put a nut on the shaft, grind down the shaft to the length needed, and then when removing the nut it will help clean up the threads on the end of the shaft. Sometimes the new engines come with a nut holding the driver washer/spacer. If not I believe the crankshaft thread is a M5-0.8