School me on engine regulations

[Chris shields]

I plan on running a built G260 PUM in my 44" Hydro. I'm going to be building the motor myself and I don't want of over step any boundaries. For example can I run a reeded motor?

 

[lohring]

In NAMBA a G1 motor must have piston port induction. If you think a reed induction motor can compete with the CMB disk valve induction or Quickdraw piston port motors you could run it in the GX1 class. In IMPBA only displacement matters. I haven't seen any reed valve engines that were more powerful than the piston port engibnes in boats.

Lohring Miller

 

[Chris shields]

Yea after much searching I saw they mainly run piston port. I'm sure a reeded motor built by me would compete with anything out there. I build at least 1 reeded motor a week. Lots of the time people don't run reeded motors cause they can get a piston port to rev higher. But this is for a few specific reasons the first being most reed blocks run fiberglass reed petals. The reed I plan to run is a large bore TS reed block with carbon fiber petals. Since boats run at mid to high rpm ranges you need to run a 2 stage reed petal. I will be running a 1mm stroker crank and .02 copper gasket. I may consider doing a long rod as well. I actually run a porting business out of my garage. My motors are smoking OBR and running par and above with Gizmo. This is more of a build for myself. I'm not to serious about racing it as there isn't much of that up here

 

[Chris shields]

Here is a case I did recently. This was enlarged almost 30% to accept an RCMK top end. That is a 3mm stroker crank with a +5mm long rod. This motor is pushing roughly 10hp for the customer.

 

[lohring]

Chris

Where are you located? I live both at the Oregon coast and in Springfield. The Emerald RC boats pond is a great place to test and we can give you a lot of help. Nice crankcase, by the way. I have an old time manual machine shop at the coast. I've been involved with engine development Since Mike Bontoft and I were the first gas boaters to set a record over 100 mph. Mike (and I) still ran the fastest gas boat so far in 2004. I have the NAMBA two lap gas scale record holding boat. The president of our club also has a gas scale boat. We would love to test, tune, and race with you. Look at the Emerald RC Boats page on Facebook. (I'm not a membeer)

Lohring Miller

 

[Chris shields]

I'm here is Salem. I would love to come race. I got a buddy with a really nice Nitro Hydro down south who want to come up too. I got a boat and then things took off. I have been building super knarly gas motors for Gopeds for years. Now I'm gonna turn that experience towards some boats. You can find me on Facebook as Chris custom scooters

 

[lohring]

We'd love to have you. When the snow melts in a month or so, we'll start having fun runs. As an aside, the requirements for a Goped motor and boat motor are very different. Boat motors run continuously at or above their peak power rpm at wide open throttle.

Lohring Miller

 

[Chris shields]

I have been studying boat porting for a while. This gives me a chance to hone that skill. You would be surprised how some of these Goped guys ride. A lot of my business comes out of Florida and they are pushing their peds for 8-15miles at a time WOT. Now think about the stress on a motor pulling a 150-250lb person turning 15-20k rpm the whole way. People come to me cause my motors take the abuse while other off the shelf ones can't handle it. The Gizmo full mod motors hang most of the time but nobody else does. I might keep this 88" boat I got around just to drop a Polini motor in

 

[lohring]

NAMBA insurance will only cover boats under 60" long with a maximum of a 36 cc gasoline engine. I would be interested in a case reed engine. We have years of engine test data from our dyno, but never have tested a reed engine. Standard Zenoah conversions don't ook like they hve big enough reeds.

Lohring Miller

 

[Chris shields]

Yea you have to be careful of what reed you choose. IMO nothing compares to Trevor Simpson reed blocks. Proline are ok but no longer in production. Bartalone reeds are to small and run fiberglass petals. I'm planning on running and older TS angle reed which keeps the flow going at a downward angle. My reed is also getting bored out so I can run an HDA series carb. The fuel required to drive the motor when reeded really starts climbing with the rpm range. I have seen the carb keep rpms down on many occasions. I am also gonna routing the pulse from the crank case directly to the carb. I am going to do a whole build thread when I get close to being done. Between work and my porting business my own personal stuff always get backburnered