Aluminum or heavy brass flywheel

[dannyual767]

I've got a K&B .82 and it came with a light aluminum flywheel. I've also got a K&B .67 and it came with a heavy brass flywheel. My old, late 70's OPS .65 came with a brass flywheel. My newer OPS .67 came with a light aluminum flywheel.

I'm sure the lighter flywheel will rev quicker but the heavier flywheel with store more energy but why and when should I use one over the other?

 

[tnrcboatracer]

The heavier flywheel will also keep the engine from overrevving when the prop comes out of the water. The extra inertia of the heavier material works both ways.

 

[Sean Bowf]

In theory, the heavier one will help idle too....but who runs at idle

Sean

 

[Ray Sametz]

The brass flywheel in a mono was said to pull better in the corners. Good paper weights.

 

[dannyual767]

So far it looks like the heavy flywheel may have some benefits, right? I guess when its time to run one of the engines, I'll try both flywheels and see how they do .

 

[Eric Bourlet]

The heavier the flywheel the more gyroscopic affect it will have so the boat will turn different. I like the smallest flywheel I can use. A smaller flywheel will also accelerate off the corners faster.

 

[shoboat]

Danny,

Flywheel weight is a non factor on most boats,it is in the crank design that matters.

Your testing results would be interesting. We have tried quite a few weights on a 21

Hydro without any real difference.

Thanks,

Mark Sholund

 

[AndyBrown]

There is a difference if you pay close attention.

You'll have to plan on testing back to back to see what YOU like best on YOUR boat.

 

[jetpack]

Seeing as the heavier one stores more energy, I would guess that could be an advantage on less wear on the engine if your prop comes out of the water often, reducing shock on the rod from the prop. Lighter flywheels are known to loose more rods from what I recall.

 

[dannyual767]

Seeing as the heavier one stores more energy, I would guess that could be an advantage on less wear on the engine if your prop comes out of the water often, reducing shock on the rod from the prop. Lighter flywheels are known to loose more rods from what I recall.

If this is true, then I think that I'd rather run the heavy flywheels.

Anyway, thanks for all the replies everyone. Like I said earlier, I think that I'll try both the heavy and light and, like what Andy said, see which one I like the best .

 

[Preston_Hall]

Everything I have seen in the past 10 years is aluminum. What does that tell you to use?

 

[Ken Retallick]

Everything I have seen in the past 10 years is aluminum. What does that tell you to use?

Aluminium is much cheaper than brass, and easier to machine than steel.

If engine manufacturers wanted to make engines to how we want, there would be nobody modifying engines