jose8986

Hello everyone, Thinking about getting back into nitro boats. Picked up a very nice CMB 21 LS Greenhead on ebay . But now Im worried about it not being strong enough to power the type of boat I want [sm=confused.gif]. Looking to build a Dumas Miss Unlimited or any shovel style hydro from G. Finley plans they range from 32" to 36", 1/10 scale. Not looking to be race competitive but would like it to be somewhat fast. What do you guys think? Also does anyone know what size pipe for this engine and were I could get one. Need a place to get spare parts for this engine too.


Thanks for you help,

Jose'

P.S. I do have some boat exp. mostly tunnels. Been building planes for years, so building from plans should not be a problem.

Dan S

32 to 36 inch for the stock CMB 21 LS may be a bit, it will work, just try to keep the weight down as much as you can.
should be able to do 35 to 40mph and maybe a bit more.
I had my Super Sport 21 Hydro at 48mph which is just shy of 30inches by a 1/4", not as good of speed compared to when my Novarossi was in it but it was decent.

a good pipe would be an OPS 3280, and if you know how to modify the engine yourself (if not if you know someone that does) you can get that CMB 21 LS a little more oomph (maximizing the ports, lightening the piston), however they are a bit hard on the con rod, upgrading to a Titanium rod would be a plus.

Dan.

jose8986

Hello Dan, Thanks for your advice. Found some plans at http://www.astecmodels.co.uk/plans.htm. They have a very good looking 1/12 scale Notre Dame hydro that is 30"long that just maybe the right size. Its made for elec. power but I should be able to convert it to nitro power. What do you think? My engine came with 2 extra pistons and sleeves, I have been playing with nitro engines since I was a teen(long long time ago) and I'm an auto tech so I will give modifying a shot to get some more rpm's out of this engine. Where can I get the pipe and rod? Been looking for parts for this engine but I haven't had any luck. Anymore advice would be great this will be for first boat in a very long time and there's a lot to learn[sm=bananahead.gif]!!!!

Thanks for your help,
Jose'

Dan S

Jose,

parts for any CMB engines in North America contact Stu Barr, [email protected]

for ops 3280 pipes, Dave, [email protected] he should have some. if your looking for quiet then this is not the pipe for you, you can however add a muffler.
3280 is one of the most sought-after pipes.

for a Titanium Con Rod, get in touch with Brad at [email protected] (I will confirm the address)
they are a bit more money than the stock rod but you won't need another one (2 stock rod is more money than 1 titanium rod).

if you want stock rods in case Brad is out of Titanium and Stu does not have any, get in touch with Jerry at Seaducer boats, check their web site for email.

Dan.

jose8986

Dan your the best .Thanks a million !!! It might be awhile but as soon as I start my boat project I'll let you know, will post pic's and I will drive you nuts with questions[sm=lol.gif]. If you ever need help with planes I will be happy to help.

Dan S

no problems Jose,

I do the plane thing also.

Dan.

Ron Olson

My Feedback: (1)

Yes, the 3280 is a loud pipe without mods. There is a little trick that for about a US dollar that will quiet it down. I'd also recommend the CMB TT pipe, it's really quiet.

jose8986

Should have known you do the plane thing. But the offer still stands Dan. Also great looking boats you have there!!!.

Ron thanks for your advice also, dont leave me hanging LOL, whats the trick?

Dan S

Thanks Jose,
I have more pics but fore some reason they are not loading into my Gallery.

After a bad flip the Blast Cat changed color to Kawasaki Green.
it is now retired due to a crash with another Cat, I lost a foot of the side of the boat which is now 50 feet deep.
I still have the Cat in the Garage (I can't seem to be able to part with it).

it could be fixed but it would be much too heavy for racing, don't know what to do with it.
the BC has now been replaced with an F-41 Stryker Cat.

Dan.

Ron Olson

My Feedback: (1)

OK, it's easier to do with a new pipe but can be done with one that has been used. First, you have to get the inside of the stinger clean. Off to the hobby shop for a piece of brass tubing that will fit inside the stinger. Cut the tubing so that it goes only as far as to where the two cones meet. Where the tubing enters the cone you want to drill a small hole for oil and water to drain out, about 1/16" or so is good. You want to mount the pipe so that the little hole is facing downward when done. A tiny screw ran through the stinger and tube will give you a little added insurance. I add JB Weld to help stick in in place also. When you're done, it's called an internal muffler.
I have shots of one that I made using a smaller pipe but it gives you the idea of what I'm typing about.

jose8986

Dan love that shade of green! I hope my boat comes out half as good as your boats.

Ron thats a great little trick thanks for sharing it with me.

I've decided to build a 1\12 size Notre Dame Hydro from Finnley plans, wish me luck[sm=drowning.gif] will try to post pics when I get started. I hope you guys are ready for a ton of questions!!! [sm=bananahead.gif]


Jose'