Motor Head Clearance Questions?

[Samuel Hagan JR]

What are the pros and cons of having low head clearance and high head clearance?

 

[RodneyPierce]

tighter head clearance helps burn the nitro (raises the compression ratio). IMHO, a high head clearance does nothing but waste power...

 

[Samuel Hagan JR]

Thanks.

Right Now I'm at .012" head clearance. It's a MAC 45. I'm not sure how low I can go and still have reliability.

 

[SayMikey]

Sam maybe you can go to .010 or even .008 but if you burn plugs it too tight. A higher head clearance will give you torque off the corner if your dragging a heavy boat. You may compensate with a bigger head volume. If your looking for more speed start at the back of the boat,prop and make sure the running surfaces are flat and sharp.

 

[RodneyPierce]

.012 is a safe number on a .45. .010 would likely be fine as well.

The above advise from Mike is good. Start with the prop.

 

[James montgomery]

Wht is a good clearance for my go 21 not sure wht it is at now it is brand new Go moter.

 

[RodneyPierce]

Your clearance in that GO is huge if its factory. Probably at about .025. A good clearance for you would be .008. You go lean when you tighten them up james, and they take a plug every time.

I would focus on getting the boat around the pond first, THEN worry about the clearance.