New CMB 21 VAC

[BB Mods's]

On my break-in stand. water testing will be some time this week, ill make sure to get video.

 

[Al Hobbs]

The crankcase casting sure is familiar. I know who designed it and who paid for the tooling.

I apologize for the sour grapes.

 

[BB Mods's]

No problem Al, I know it was all a crappy deal for those involved.

 

[Al Hobbs]

Thanks,

Al Hobbs

 

[tnrcboatracer]

The case casting looks like it is common for either the rear exhaust of front exhaust. Notice the screw boss lugs for the rear cover on the exhaust port side. Also, looks like there was structure of a front end above the rotor housing where a crank induction carb would be. Basically looks like the case was cast with two front ends, and which ever isn't used is cut off. Interesting way to save $$ on casting dies. Anyone seen one of the latest car or RS motors from CMB?

 

[BB Mods's]

Yea, Iv got a rs case sitting here, but it's not even close to the same casting, I see what your saying, but Novarossi and others have done that for years, Al might be able to tell us why that is.

 

[tnrcboatracer]

I was looking for pics of the 2010 RS, but haven't found any yet. The VAC may be the first engine to use the new die. We also need to look at the car motors as they seem to have a shorter design life cycle.

 

[dwb2620]

I know this might be a dumb question, but what does the "VAC" stand for? On a side note if you draw 2 lines from the top of the "V" it would make a M, then you would have a " MAC". That is my sad attempt at humor for today. h34r:

David

 

[BB Mods's]

cmb's are not die-cast, there lost wax cast

 

[Al Hobbs]

For the prices they charge for the moulds, I know that they try to make the moulds work for as many different engines and engine updates as possible. You can use the same outer mould, but a different inner mould as is often the case for a 67 and an 84. The idea is that expensive moulds are a big cost of marine engines. Let's say it only costs $10,000 for a mould. Spead out over 1000 engines, this means a cost per engine of $10. A mould cost of $10,000 spread out over only 200 engines means a cost per engine of $50. So, if the mould can be used to produce different brands and engine sizes, the cost per engine goes down over time.

These factories value the moulds they are using. They want the moulds to be as versatile as possible.

One way to make the moulds work for as many different engines as possible is to not put the brand name into the mould, but engrave it onto the crankcase later.

So, the mould paid for by MAC 21 engines, was used for CMB 21 engines. All that had to be done was engrave MAC or CMB into the crankcase depending on which brand was being built.

I know that PICCO makes many different car engine brands. I don't know if they use the same moulds to make several different brands or not.

I don't know that much about the NovaRossi moulds, but I do know that NovaRossi also makes many different brands. Perhaps they use the same moulds for different brands as well. Someone on IW would know about this better than I do as I have not visited the NovaRossi factory. I have visited PICCO, Rossi and CMB.

In some instances, the individual brand owns the moulds. The moulds are only used to produce one engine brand and cannot be used to produce another engine brand. This was supposed to be the case for the MAC engine moulds. This is the case with the A/A 45 engine. The A/A brand owns the A/A 45 crankcase mould and this mould can only be used to produce A/A 45 engines. There is a written agreement between A/A and Rossi.

I agreed to use the Rossi car engine crankcase mould to keep the A/A 21 SLS cost as low as possible. This helps reduce both the Rossi and A/A cost per crankcase casting. A good mould will hold its tolerances and last for years. But, when you pay for a quality mould, your hand shakes as you write the check.

 

[aaron alberico]

Al

yes, Novarossi make several different branded motors, J.P Black, Max Power, etc.etc

and a lot of them use the same moulds(and parts) as the Novarossi motors,

regards Aaron

 

[BB Mods's]

Hey guys, back on track

 

[Richard Dahlheimer]

Hey guys, back on track

Hey Tommy, patiently waiting on the test results of the new blue head CMB .21 torque monster. Richard D

 

[BB Mods's]

Wife said I have to shampoo the carpets this weekend, But ill be on the water all next week and weekend

 

[Richard Dahlheimer]

Wife said I have to shampoo the carpets this weekend, But ill be on the water all next week and weekend

ok, sounds good. Did you ever try the new induction on a .21 RSV? (3 exhaust port motor) I remember reading that you ran the new in-line on a MAC. Richard D

 

[BB Mods's]

Funny you should ask, The only redhead RSV valvola I ever owned was stolen out of my motor box at the pond 2 years ago, broke it in, but never ran the thing, if you have a RSV valvola, snatch the back plate off and send it this way, ill let you know how it works out Or if you buy a vac carb from Stu, Ill loan you a intake and rotor.

 

[Richard Dahlheimer]

Funny you should ask, The only redhead RSV valvola I ever owned was stolen out of my motor box at the pond 2 years ago, broke it in, but never ran the thing, if you have a RSV valvola, snatch the back plate off and send it this way, ill let you know how it works out Or if you buy a vac carb from Stu, Ill loan you a intake and rotor.

Thanks for the offer Tommy, but i bought one of the 1st generation motors that is based on the RSV. Motor has the RSV case and piston and liner. The intake system, crank and rod is new generation. I bought the engine set-up from Steve Wood. Piston and liner is very tight, and have only ran about 3 quarts of fuel in it so far. To early to tell how good this engine is. Sorry to hear about your stolen motor. Richard D

 

[BB Mods's]

Did some testing with a few new props in the speed master 21 mono this past weekend, had a ruff day Friday trying to break in my spare p/s when my remote needle took a dump, Saturday was spent putting more fuel through the motor with a normal non-3rd chan needle (os 40la needle) While I kept the boat way on the rich side, we made a bunch of 50mph passes down the front straight, The pipe was a full length CMB 21 nitro pipe with no header (pipe was @ 8 1/4" ) So I know it has a bunch left in it!

This week/weekend will be spent testing pipe length/rpm/mph with my original p/s set that is fully broken-in now Still no detonation on the stock setup with the squish set @ .006, and even though my low speed needle is removed, getting off and on the throttle was not as bad as most carbs act, 7 out of 10 times I was able to fully recover, and make it back on pipe b4 the end of the straight!

Still having lot's of fun playing with this new motor, Cant wait to drop it in the new Jag B)

 

[Marty Davis]

Did some testing with a few new props in the speed master 21 mono this past weekend, had a ruff day Friday trying to break in my spare p/s when my remote needle took a dump, Saturday was spent putting more fuel through the motor with a normal non-3rd chan needle (os 40la needle) While I kept the boat way on the rich side, we made a bunch of 50mph passes down the front straight, The pipe was a full length CMB 21 nitro pipe with no header (pipe was @ 8 1/4" ) So I know it has a bunch left in it!

This week/weekend will be spent testing pipe length/rpm/mph with my original p/s set that is fully broken-in now Still no detonation on the stock setup with the squish set @ .006, and even though my low speed needle is removed, getting off and on the throttle was not as bad as most carbs act, 7 out of 10 times I was able to fully recover, and make it back on pipe b4 the end of the straight!

Still having lot's of fun playing with this new motor, Cant wait to drop it in the new Jag B)

I had a chance to build the 2009 CMB 21 with the new VAC Backdoor and the engine ran great with good torque and good rpm. I can see that the new back door assy is really a great way to pep up one of the earlier CMB's. Now, I will put it on one of the MAC's that I have been running and see if it is better than the original assy and carb that I have run for several years. Should be interesting.....

 

[BB Mods's]

Glad the parts made it to you safe Stu does a great job keeping track of all our parts :lol:

Must be doing something right, got a set of super light sponsons for my 90 SAW boat in the mail, Only problem is they say Crapshooter instead of SNT Marine

Thanks for everything guys! I look forward to more open water