Pictures back up within page 1 posts.

*Note, pictures may not be in right location, but you still get a good idea on whats going on.

Thanks scott, can you explain the performance difference you are getting from that piston design compared to the standerd mod pistons that everybody else makes. Also i have another question for you, why doesent anybody talk about ignition timing, how much further can we go on our little motors without detonation, and can it help our low compression motors make more power? Sorry for the loaded question in the wrong trend.

The ignition timing issue has been beat to death with the final conclusion being the factory 28/30* BTDC specs work the best .... PERIOD !

The vented piston is just a way around having larger transfer runners. We only have so much material cast, and the size of transfer passages is pretty much set in stone.

By allowing such volume of air/fuel to pass right threw the sides of piston, you deliver a much larger flow at the actual port window.

Another up side is you get increased flow potential without adding larger transfers and increasing the case volume in doing so.

* Down side is with flow coming up the passages from the crankcase and then being merged with the flow coming threw piston, the smoothness and equal flow out transfer window gets disturbed to some degree and the low to mid power band can suffer.
But this degree of disturbance can be minimized by careful attention to the matching of pistons slots and sides of transfer runners. Gains are really at the upper range of RPM. Piston is so light vibration is far less and piston seizures are tough too do because it is cooled so well from being vented.

Hope that helps ya

Thanks scott your reads are always cool. With my moters that have the timing advanced thay seem to have more torque throughout the powerband, am i doing something wrong or should i have the port work done different.

A few more degrees of ADVANCE will add torque, but at the expense of top end RPM and ultimate HP produced by engine.

I set my boats up for heat racing and turn anywhere between 16800 to 17400 at aroung 58 to 59 mph. Just looking for more like everyone else.

50 stowe wrote:
One word .... FUEL

Should i back off the ignition timing and go with camp fuel to get more rpm. Scott when ya get a chance check out my mono run in the general gas section, second page under aeromarine 43 stingray.

As a self tuner, ONLY way to satisfy yourself on what combo is best .... TEST TEST TEST

This thread here on MGB gives you a better idea on schools of thought
www.modelgasboats.com/index.ph...atid=14&id=5154

Hello Scott
what rpm does this engine got.