bigger flywheel?

[jeffgnz]

I have an HSP 1/8 monster truck which has a little SH .18 engine on it, which I believe is more of a 1/10 scale engine. The problem I am having is I would like to use my starter box with the truck because the pull-starter is a pain in the ****, but the engine is mounted up on blocks (I believe because its small for the size of the truck).

This means the flywheel sits up quite high and there is no way of it reaching the bump start wheel on the starter box.

After a bit of research I've looked into a couple of options:

1. Lowering the engine -- the issue here is that this will affect the whole drivetrain and I would need to make lots of other modifications to get it to work. It doesn't seem feasible to me.
2. Getting a bigger flywheel -- the current flywheel is about 38mm in diameter. I've done some searching and haven't found any bigger ones available. One I found was 40mm, not big enough to make a difference.

So I have reluctantly concluded that I'm stuck with pull-starting it ... hence my questions.

1. Is it easier than I think to lower the engine?
2. Are there any bigger flywheels out there?
3. Have I missed another option?

EDIT: The third option of course is a drill starter, but I already have the starter box so I'm exploring that option.

 

[cbaker65]

I have an HSP 1/8 monster truck which has a little SH .18 engine on it, which I believe is more of a 1/10 scale engine. The problem I am having is I would like to use my starter box with the truck because the pull-starter is a pain in the ****, but the engine is mounted up on blocks (I believe because its small for the size of the truck).

This means the flywheel sits up quite high and there is no way of it reaching the bump start wheel on the starter box.

After a bit of research I've looked into a couple of options:

1. Lowering the engine -- the issue here is that this will affect the whole drivetrain and I would need to make lots of other modifications to get it to work. It doesn't seem feasible to me.
2. Getting a bigger flywheel -- the current flywheel is about 38mm in diameter. I've done some searching and haven't found any bigger ones available. One I found was 40mm, not big enough to make a difference.

So I have reluctantly concluded that I'm stuck with pull-starting it ... hence my questions.

1. Is it easier than I think to lower the engine?
2. Are there any bigger flywheels out there?
3. Have I missed another option?

EDIT: The third option of course is a drill starter, but I already have the starter box so I'm exploring that option.

The only fly wheel that I know that was huge was on the old AE RC10's ,back in the day ,they used bump starters on
them an did not have a pull start assembly on them!
I have a custom B-block 21 street car that had to have a drill starter put on due to lack of space in the car ,I don't know
about the engine you run ,or the way the one-way bearing is on the current starter ,but the drill start in my opinion
would be the way to go.

Why is your pull start a pain in the butt?

It shouldn't be hard to start!
1. Maybe too cold.
2. Engine still has a hella of compression.
3. Your engine is tuned too rich causing a little hydraulic lock.

These will cause the engine to be hard to start with a pull starter!...

Heres my B-block Hyper 21 in a 1/10 Ofna Ld3 street car.
The drill start is right under the exhaust coupler ,its an angle type!

 

[jeffgnz]

Hi, thanks for the reply.

Why is your pull start a pain in the butt?

The pull starter has always taken ages to get the engine started. It never starts with the first few pulls like they seem to in the videos. I don't think its a hydrolock or compression issue because it will pull easily enough, it just takes ages before it will fire. At this point in time the pull start cord has actually broken, and I've replaced it with a drill start back plate, but its a back facing one and not easily accessible through the back of the truck.

Heres my B-block Hyper 21 in a 1/10 Ofna Ld3 street car.
The drill start is right under the exhaust coupler ,its an angle type!

I have an older XTM XT2 which has an angle drill start just like that one. The drill start back plate that I got for the MT unfortunately isn't compatible with the drill starter that came with the XT2, and as mentioned access through the back of the truck to reach the back plate is difficult even if it did work.

When I got the XT2 it didn't go and I've managed to get it running and now it starts like a breeze with the starter box, so I really wanted to get the MT going with that as well.

Like you suggest, I think I might persevere with trying to get the drill start to work, and if that fails buy a new pullstart back plate for the engine. The biggest issue with the drill start is that it takes a dogbone shaped fitting but the XTM drillstarter takes a hex-ball type fitting, so the drillbits either don't fit the starter or the backplate depending on which one I try I might be able to figure out a work-around for that.

Thanks so much for your help, its pointed me in the right direction.

 

[cbaker65]

Hi, thanks for the reply.


The pull starter has always taken ages to get the engine started. It never starts with the first few pulls like they seem to in the videos. I don't think its a hydrolock or compression issue because it will pull easily enough, it just takes ages before it will fire. At this point in time the pull start cord has actually broken, and I've replaced it with a drill start back plate, but its a back facing one and not easily accessible through the back of the truck.


I have an older XTM XT2 which has an angle drill start just like that one. The drill start back plate that I got for the MT unfortunately isn't compatible with the drill starter that came with the XT2, and as mentioned access through the back of the truck to reach the back plate is difficult even if it did work.

When I got the XT2 it didn't go and I've managed to get it running and now it starts like a breeze with the starter box, so I really wanted to get the MT going with that as well.

Like you suggest, I think I might persevere with trying to get the drill start to work, and if that fails buy a new pullstart back plate for the engine. The biggest issue with the drill start is that it takes a dogbone shaped fitting but the XTM drillstarter takes a hex-ball type fitting, so the drillbits either don't fit the starter or the backplate depending on which one I try I might be able to figure out a work-around for that.

Thanks so much for your help, its pointed me in the right direction.

No problem .I might have an old RC10 bump start fly laying around ,I can search for it an check the measurements
of it!...

 

[cbaker65]

What I have it measures an 1 1/2'' ,you would have to refigure in mm's!...

 

[jeffgnz]

What I have it measures an 1 1/2'' ,you would have to refigure in mm's!...

Thanks for doing that. 1 1/2" is 38mm which is the same diameter as mine.
On with investigating the drill starter ...

 

[jeffgnz]

Just an update on this in case anyones interested. So I bought the drill bit needed for the drill starter. While waiting for the slow boat from China I got impatient and cut the opening in the chassis plate bigger to make better access to the flywheel. I also removed the spacers/risers off the top of the starter box and managed to get it to reach the flywheel. Reversed the polarity on the motor because I have to face the truck the other way from my buggy (note to self, don't forget to change it back). Then a happy afternoon re-tuning my engine which hasn't been run in months. Thanks @cbaker65 for your help pointing me in the right direction.

 

[cbaker65]

Just an update on this in case anyones interested. So I bought the drill bit needed for the drill starter. While waiting for the slow boat from China I got impatient and cut the opening in the chassis plate bigger to make better access to the flywheel. I also removed the spacers/risers off the top of the starter box and managed to get it to reach the flywheel. Reversed the polarity on the motor because I have to face the truck the other way from my buggy (note to self, don't forget to change it back). Then a happy afternoon re-tuning my engine which hasn't been run in months. Thanks @cbaker65 for your help pointing me in the right direction.

Thank you!...

You also might can find a different size starter wheel for your bump starter ,if I'm not mistaking ,I think that I've seen replacement
starter wheels for them over the years that I've been involved in RC's!....

 

[Rolex]

If you're handy with electric you can add a toggle switch that will reverse the polarity for different engines. Off the top of my head, I believe it would be a double pole, double throw.

 

[jeffgnz]

If you're handy with electric you can add a toggle switch that will reverse the polarity for different engines. Off the top of my head, I believe it would be a double pole, double throw.

Good idea thanks, I will give that a try