CMB45RS

[Jerry Wyss]

Hi guy's, I'm installing the above engine in a old PTSS45 for a friend and I got .025" headspace the

way it came. Does anyone know if I should keep it there for 60% or take the .008" shim out and

run with .016" H/S??

The bubble volume looks slightly smaller than a Blackhead Picco 45 button but I haven't really measured it.

JDub

 

[Russell Bear]

Hi guy's, I'm installing the above engine in a old PTSS45 for a friend and I got .025" headspace theway it came. Does anyone know if I should keep it there for 60% or take the .008" shim out and

run with .017" H/S??

The bubble volume looks slightly smaller than a Blackhead Picco 45 button but I haven't really measured it.

JDub

I'm running mine at .016" with 50% fuel no problem. My head button measured at .39cc

 

[Jerry Wyss]

Sounds good to me Russ, Thanks!

JW

 

[steve wood]

i've measured 6 cmb 45's this spring. 1 hydro, 3 rs's,and 2 purple heads. they were all .35 cc. i increased them all to .38. i set the head clearance to .010 on all 6.

 

[Jerry Wyss]

i've measured 6 cmb 45's this spring. 1 hydro, 3 rs's,and 2 purple heads. they were all .35 cc. i increased them all to .38. i set the head clearance to .010 on all 6.

Good Gawd! Ten Thousandths! What kinda Motor is This Thing!,,, Pipe is set @ 9 to 10 Inches,, I'm gettin' a little

worried messin' wid this $540 motor.

The pipe I got (well, Jim Hill got) from Hallam Marine is the Copper QHP 45 pipe with the twin exhaust. There isn't

a clear indication of where on the pipe that measurement is taken. I'm assuming it's at the first weld where it

looks like the two pipe "cones" are welded together and another weld (just aft) where it again "looks"

like the silencer "can" is welded on.

Can anyone verify this location that I described as the measuring point?

Jerry

 

[steve wood]

i've measured 6 cmb 45's this spring. 1 hydro, 3 rs's,and 2 purple heads. they were all .35 cc. i increased them all to .38. i set the head clearance to .010 on all 6.

Good Gawd! Ten Thousandths! What kinda Motor is This Thing!,,, Pipe is set @ 9 to 10 Inches,, I'm gettin' a little

worried messin' wid this $540 motor.

The pipe I got (well, Jim Hill got) from Hallam Marine is the Copper QHP 45 pipe with the twin exhaust. There isn't

a clear indication of where on the pipe that measurement is taken. I'm assuming it's at the first weld where it

looks like the two pipe "cones" are welded together and another weld (just aft) where it again "looks"

like the silencer "can" is welded on.

Can anyone verify this location that I described as the measuring point?

Jerry

what? you think this is too much. we run .007 on 21's. 012 on 67 and 80's. maybe we could go to .008 if the piston won't hit the head.

 

[Jerry Wyss]

Hi Steve, .010" seems tight for the little tiny prop that was bought with with this engine. The prop has been worked

by Hallam (I guess) and he worked it so much that the info on the prop hub is gone, mostly. It looks like

a Octura 1650, but I can't be sure. But you did say that you increased the button volume so, you know more

about this engine than I do. I'm just the guy thats making it all fit in his boat as a favor. I'll probably run-in

the engine @ .016" , the headspace will likely grow atleast 1 to 002" and I'll consider making your adjustment

after that.

The possibilty of a 9" pipe length is something totally new to me on a 45 IB engine.

 

[Jerry Wyss]

I got a request from the owner of the RS I've been working on,, he wants to know if there's a "square drive"

nut available for this engine. Anybody know?

JW

 

[steve wood]

Hi Steve, .010" seems tight for the little tiny prop that was bought with with this engine. The prop has been workedby Hallam (I guess) and he worked it so much that the info on the prop hub is gone, mostly. It looks like

a Octura 1650, but I can't be sure. But you did say that you increased the button volume so, you know more

about this engine than I do. I'm just the guy thats making it all fit in his boat as a favor. I'll probably run-in

the engine @ .016" , the headspace will likely grow atleast 1 to 002" and I'll consider making your adjustment

after that.

The possibilty of a 9" pipe length is something totally new to me on a 45 IB engine.

stock head with .016 clearance= 9.1:1 comp ratio

.38 with .009= 10.1:1= more torque. these motors have HIGH exhaust timing=rpm and low torque.

 

[Jerry Wyss]

stock head with .016 clearance= 9.1:1 comp ratio.38 with .009= 10.1:1= more torque. these motors have HIGH exhaust timing=rpm and low torque.

Great info Steve, I was nervous about the disassembly and measuring the engine just for checking

timings. I know very little about CMB engines, I was expecting very low exhaust port timing and a large

button volume considering how short some guys are running they're pipe's. 9" wouldn't lead you to believe

it has a high exhaust port timing, must be the construction of the pipe that I don't understand.

The Owner of this engine bought a prop with this motor and it's a very small-ish one, maybe 9.1:1 is

a good area for the prop he got,, what'cha think?

JW

Edit: I worked out some things with Steve, he's going to set some stuff on the engine and mod a button to his

specs for possibly running larger props on the thing and keep one button stock for the smaller prop we have.

The best of both worlds, what else could you ask for?

 

[Jerry Wyss]

We're doing "this" to your new engine Jim! Seen ya lurkin' aroun' there.

JW

 

[Jerry Wyss]

I got Jim Hills new CMB RS 45 back from Steve Wood a few weeks ago and I'm glad I sent it to Steve cause he found

a factory problem in it that would have definetly affected the way the engine would perform. We just ran it for the first

time this morning and it is a Hot Rock for sure. 65% O'Donnell, MC9 plug, P-240 prop with QHP pipe @ 9.5" and one of

Steve's modded buttons @ .010" H/S. Very impressive! Thanks Steve!!

JW

 

[Andy Greene]

I got Jim Hills new CMB RS 45 back from Steve Wood a few weeks ago and I'm glad I sent it to Steve cause he founda factory problem in it that would have definetly affected the way the engine would perform. We just ran it for the first

time this morning and it is a Hot Rock for sure. 65% O'Donnell, MC9 plug, P-240 prop with QHP pipe @ 9.5" and one of

Steve's modded buttons @ .010" H/S. Very impressive! Thanks Steve!!

JW

What kind of hull is it in Jerry ?

 

[Hill Jim]

I got Jim Hills new CMB RS 45 back from Steve Wood a few weeks ago and I'm glad I sent it to Steve cause he founda factory problem in it that would have definetly affected the way the engine would perform. We just ran it for the first

time this morning and it is a Hot Rock for sure. 65% O'Donnell, MC9 plug, P-240 prop with QHP pipe @ 9.5" and one of

Steve's modded buttons @ .010" H/S. Very impressive! Thanks Steve!!

JW

What kind of hull is it in Jerry ?

PTSS45

Jim

 

[Jerry Wyss]

The "boat type" was in the first post, boat and motor belong to Jim Hill. I bought the new hull from

Phil 12 or 13 years ago and have supported Jims intrest in running sport 40 since he bought it

from me 2 years back.

The RS has already matched the best speed of the Picco disc motors he and I were using,, on the

first day out! But speed and reliability aren't the key factors to winning races but it sure makes "trying"

to win allot more fun, yeah Jim?

JW

 

[Hill Jim]

The "boat type" was in the first post, boat and motor belong to Jim Hill. I bought the new hull from Phil 12 or 13 years ago and have supported Jims intrest in running sport 40 since he bought it

from me 2 years back.

The RS has already matched the best speed of the Picco disc motors he and I were using,, on the

first day out! But speed and reliability aren't the key factors to winning races but it sure makes "trying"

to win allot more fun, yeah Jim?

JW

Yeah, for sure. :lol:I absolutely love this hull and class. To say you have supported my intrest in running sport 40 could be the biggest under statement you've made in some time. It doesn't mater how bad i screw it up you say " well let me take it home and fix it for you" or you tell me just what i need to do and, or what to get. It doesn't stop there, what about the tunnel hulls.

How many engines have you built me over the past few years. Lets not forget the support you have given me in sport 60. Talk about someone going above and beyond to help out a newbe.

As for going fast, havn't found a boat to fast yet, just to small of pond. The RS is showing great potential.

Thanks for all you do

Jim

 

[Jerry Wyss]

It's fun being involved with your boats cause I haven't had to row after them when they go upside-down :lol:

Plus, that is a fun motor to run so far, starts easy, responds well to adjustments and it GLH!!

JW

 

[Hill Jim]

It's fun being involved with your boats cause I haven't had to row after them when they go upside-down :lol: Plus, that is a fun motor to run so far, starts easy, responds well to adjustments and it GLH!!

JW

Jamie goes to the gym, I row after boats

Jim

 

[GRoth265]

B) Hey Jim; Several of us are now running the CMB in our mutts. The motor has proved to be very strong but it likes LOTS of fuel! I stumbled onto a pipe that seems to work very well with this motor. PM me if your interested. Greg Roth