CMB VAC 21 engine - Is it any good ??????

[Shane Bastick]

Does anyone have thoughts on the CMB 21 VAC engine, I was wanting to use a couple of them in a twin rigger, but have heard mixed opinions on the engine, especially for a single rigger, someone advised not to use the engine, maybe the first run was no good ?????,

any comments welcome - I am hoping it is a good engine, as CMB engines in general are good

 

[julianconde]

21 VAC engines are good if you know what you are doing. I have seen a few run on single engine riggers and they have been ballistic in the right hands

;-)

 

[Shane Bastick]

Thanks Julian, I guess its like anything, use it correctly and there should be no problems, I would have thought if there had been any issues early on when they were released, that by now they would be rectified anyway

 

[Chris Wood]

I am going to be brutly honest with you. you are better off running a nova rossi.

I have tried and tried and tried and tried and tried. oh and tried to get that motor to work in a hydro. me and dad spent ALOT OF TIME and EFFORT on it.

We could never ever get it to work. nova is tried and tru. proven. works out of the box.. better with some work done to it.

I am not saying that the vac or valvola or what ever it is called can't be made to run. I am just suggesting that takes alot of work by people that are appriantly way smarter than me and dad to get it done. if you look at the race results and see what is winning that should answer your question.

i do think they seam to work well in MONO'S.

just my opinon.

chris

 

[NITROSNIFER]

I agree I could not get the Valvola to run great in my JAE .21. It went well just not as fast as I would like. Dropped a 5 port Nova in the same hull no changes and it screamed. Put the Valvola into my mono and it screams ????? I figured the Valvola was just being picky and did not like the wood grain on my rigger. Mono's red... maybe if I add green and white it will go even better :blink:

 

[anthony_marquart]

Good old NR5p...

 

[Butch Londrigan]

mine is getting there. Ran last weekend with Rodney Pierce 21 rigger Mike Larson at wheel. His was faster but its close. The motor takes right off no dead boat or cant get on plane. I got some mods from Mark Grim and seems to be working for me. I wont knock NR they are great motors. I whish they would come out with a front ex motor hate the 180 header

 

[anthony_marquart]

RP's boat is fast,.. and he has a high end NR,.. I too wish they had a front exhaust motor.. so much easier to set up in a boat..

 

[Tim Kish]

Olly has I believe an Orlic prepped VAC that's running strong .

Tim

 

[dave roach]

I have a friend running a Dave Roach prepped Vac21 blue head in a sport 20 and running very strong.No problems here.You have to have a good piston and sleeve fit.

Dave

 

[dwb2620]

Timing too high on this motor?

 

[anthony_marquart]

sounds like all the strong runners are "prepped" by someone. I like the idea of not having to have a machine shop and precision tools to get the motors to run correctly.

I know there are better motors,.. but the little old NR5p with a smaller volume head button, and clearance set to about 0.008, runs pretty darn hard...

 

[David Bryant]

I like the idea of not having to have a machine shop and precision tools to get the motors to run correctly

exactly

 

[dave roach]

I beat Steve Wood Doesn't take a engine out of the box and put it in a boat and run it.

Dave

 

[anthony_marquart]

I'm not saying you shouldn't open it up and check for burrs and such.. but I would think that by now we could get a engine to run in our application without having to cut it.. I really like the NR engines myself but the head volume it really too large on it stock. Fortunately anyone can buy the head button and pop it in there real easily.

But, you know what? I changed my mind.. You should be able to do that.. for what we pay for these motors, you should be able to take it out of the box and run it..

 

[tobbec]

Its hard to get o motor to just get out of the box.. i wonder if there is any...

 

[Butch Londrigan]

My vac has more torque than my valvola had. Thats way it works beter in a mono or hydro. riggers need torque to get on plane. The fastest boat doesn't win all the time. (NEED TO FINISH)

 

[Butch Londrigan]

The more motors we have to choose from the better the sport is. Would not be any fun watch fords win every weekend.

 

[RodneyPierce]

mine is getting there. Ran last weekend with Rodney Pierce 21 rigger Mike Larson at wheel. His was faster but its close. The motor takes right off no dead boat or cant get on plane. I got some mods from Mark Grim and seems to be working for me. I wont knock NR they are great motors. I whish they would come out with a front ex motor hate the 180 header

Anthony, It WAS NOT my rigger. It was Mike's AJM rigger I assume? I wasnt at the pond last weekend, and this particular CMB is about 16-17mph off from my 35+ in my AJM 21 rigger per a stalker radar gun. And Butch your correct. Have to finish to win. Fastest boat doesnt always finish.

 

[Shane Bastick]

So all in All - what is the general view on the 21 VAC - I dont race, but still want the boat to be fast - I just dont like a boat with a 180deg header, otherwise Novarossi's would be fine. Has anyone used a CMB 21RS red head - is that any good - I own both of these CMB 21 engines plus a MAC 21, and are not sure what to use.