CMB 80RS-H sleeve breakage??

[Don Ferrette]

I've got a customer who wants me to set him up with an 80 powered hydro & asked about the red head CMB 80RS-H. To date I have heard countless number of people who are having the sleeves crack at the finger port CMB added to the RS-H sleeve with pieces going thru the motor. Anyone know if CMB, or anyone else for that matter, has come up with a fix for this?? Since there are no MAC's to be had this is the guy's only other option but I have yet to find anyone who hasn't broken one. :blink:

 

[Bob Finn]

I've located one new 80 P+S, and I may come up with another from a friend. Will let you know later this evening.

 

[Tim_Duggan]

Does the green head 80HR piston and sleeve fit?

 

[Chris Wood]

Don, and others.

First of YES the 80 green head sleeve drops right in.. problem is getting the sleeve.. they don't make them any more and i am not sure if stu has any.

I heard a guy in indiana talking to dad and me dad have discussed this.. I think the sleeves are cracking because of high rpm harmonics.

This guy in indiana that dad talked to said he lowered the sleeve to make the exhaust timing 180 degree's and it runs just as good as 187 or whatever stock is.

This is in a seaducer mono.

I do know we cut out the bars that was cracking on the sleeve which are next to the exhaust.. then the otherside broke.

hope i helped.

chris

 

[Tom David]

Hello Don,

My name is Tom David, and I am the boater that Chris is referring to from Indiana.

First let me say that I agree with Chris and Steve Wood about the possibility of RPM

harmonics causing some of the sleeves on the RS 80’s to crack at the finger port.

I am not a well known boater from Evansville, Indiana. But I have many years

of experience setting up 80 size nitro engines in Mono Hulls. About one year ago

I set up a new CMB 80 RS in a Seaducer 60/80 Mono Hull. I never was able to

obtain the performance level I was looking for with this stock engine turning a

X462 on the Seaducer hull.

After spending many hours at the lake testing and cracking several sleeves, I went to

the work shop and put on my thinking cap for a solution. I decided to drop the high

exhaust timing of the RS sleeve down to 181 degrees. I did this by cutting .016 off

of bottom of the flange on the sleeve. This dropped the sleeve in the case and brought

my exhaust between 181-182. I did NOT change anything else on the sleeve. Using

Steve Wood’s .68cc head button with a flat squish band I set the deck at .011. On

my engine it took .020 of shims to reach the .011 deck clearance. By the way,

this timing now is almost the same as the CMB Green Head 80. (intake and exhaust)

I am using the new Cooper muffled pipe for my testing. The fuel is 50%, 18% oil.

On a very humid day I tested my set-up. Pipe set at 11.5 turning an X462 I was able to

Clock in with several 12 second laps. What really made me happy -- I never replaced

The MC-9 glow plug after five runs. Also never cracked the sleeve.

Of coarse this is a mono and not a hydro. But I am convinced if you make this mod

I described, you can reach the same level of performance as the green 80. Maybe even

better because of the geometry at the transfer and boost ports and the added finger port of the 80 RS sleeve.

Happy Boating

 

[aaron alberico]

Guy's

here we go...

i have put 5 brand new piston\liner in my 80,,

since end of last year.. :angry: :angry:

the last 3 outing s have been new p\s and they only last the event and brake and gone

through my engine... :angry:

in my last p\s i removed the little bit of liner between transfer and finger port,

it lasted a weekend before the liner broke between the finger port and the

exhaust port.. that's right it took the section of liner right out and through the engine..

i have run this engine in outrigger and a seaducer mono..

the sad thing is they have awsome RPM'S and grunt...

or thats because i no someone who know's how to work these things lol... :lol:

its happen to both stock and mod liners

regards Aaron

 

[Tom David]

Hello Don,
My name is Tom David, and I am the boater that Chris is referring to from Indiana.

First let me say that I agree with Chris and Steve Wood about the possibility of RPM

harmonics causing some of the sleeves on the RS 80’s to crack at the finger port.

I am not a well known boater from Evansville, Indiana. But I have many years

of experience setting up 80 size nitro engines in Mono Hulls. About one year ago

I set up a new CMB 80 RS in a Seaducer 60/80 Mono Hull. I never was able to

obtain the performance level I was looking for with this stock engine turning a

X462 on the Seaducer hull.

After spending many hours at the lake testing and cracking several sleeves, I went to

the work shop and put on my thinking cap for a solution. I decided to drop the high

exhaust timing of the RS sleeve down to 181 degrees. I did this by cutting .016 off

of bottom of the flange on the sleeve. This dropped the sleeve in the case and brought

my exhaust between 181-182. I did NOT change anything else on the sleeve. Using

Steve Wood’s .68cc head button with a flat squish band I set the deck at .011. On

my engine it took .020 of shims to reach the .011 deck clearance. By the way,

this timing now is almost the same as the CMB Green Head 80. (intake and exhaust)

I am using the new Cooper muffled pipe for my testing. The fuel is 50%, 18% oil.

On a very humid day I tested my set-up. Pipe set at 11.5 turning an X462 I was able to

Clock in with several 12 second laps. What really made me happy -- I never replaced

The MC-9 glow plug after five runs. Also never cracked the sleeve.

Of coarse this is a mono and not a hydro. But I am convinced if you make this mod

I described, you can reach the same level of performance as the green 80. Maybe even

better because of the geometry at the transfer and boost ports and the added finger port of the 80 RS sleeve.

Happy Boating

I need to also mentioned that after I tested this set-up, I have ran 4 gallon of fuel

through my 80 RS with no failures.

 

[Bob Finn]

Don - E-mail me. I dug around and found 4-5 80 P+S. [email protected]

 

[Don Ferrette]

Don - E-mail me. I dug around and found 4-5 80 P+S. [email protected]

you got mail.

 

[Don Ferrette]

So did all the red head 80's get this new sleeve or only the 2007 models?? :unsure:

 

[Tom David]

So did all the red head 80's get this new sleeve or only the 2007 models?? :unsure:

If you are referring to the added finger port as the new Sleeve, then the answer

is yes. All 80 RS Red Heads that I have seen have this new Sleeve.

Port Timing is also different when compared to the 80 Green Head Sleeve.

 

[mark voorhies]

So did all the red head 80's get this new sleeve or only the 2007 models?? :unsure:

If you are referring to the added finger port as the new Sleeve, then the answer

is yes. All 80 RS Red Heads that I have seen have this new Sleeve.

Port Timing is also different when compared to the 80 Green Head Sleeve.

Tom , thanks for sharing your sleeve mod on the .80 RS Red head, I think you may have somethin there,

hasn't been any other improvements to keep that sleeve together, you have the best test so far!!

 

[tnrcboatracer]

Can someone post a pic of the ports on this sleeve or give a web address where I can see it? Thanks.

 

[aaron alberico]

go to www.ozspechobbies.com

and click on cmb engines go right to bottom of page

last line of picture's in the middle

regards Aaron

 

[tnrcboatracer]

Thanks. The big bore sleeves are beginning to look like hte NR 21's. Not much metal there to connect the upper and lower sections. Are all those extra ports on the larger engines necessary? Are they really that effective? Looking at the older CMBs, the OPS67/80, and the MAC 67/80 these extra ports don't seem necessary. I never thought my MAC's or OPS90 lacked for intake flow or scavenging.

 

[steve wood]

Thanks. The big bore sleeves are beginning to look like hte NR 21's. Not much metal there to connect the upper and lower sections. Are all those extra ports on the larger engines necessary? Are they really that effective? Looking at the older CMBs, the OPS67/80, and the MAC 67/80 these extra ports don't seem necessary. I never thought my MAC's or OPS90 lacked for intake flow or scavenging.

the added finger port on thr rs 80 deffinately made more power, but will not last. i cracked two before i gave up on them and went back to a modded green head piston and liner.

 

[Stuart Barr]

I have 4 80 RS's that have been run for two years now with no failures. I use a "Sunnen Hone" to improve the liner finnish and I believe this has corrected the failure of the narrow port areas. Tom David has a good idea also on his fix. I have seen his engine run and it is very powerful.

 

[Don Ferrette]

I have 4 80 RS's that have been run for two years now with no failures. I use a "Sunnen Hone" to improve the liner finish and I believe this has corrected the failure of the narrow port areas. Tom David has a good idea also on his fix. I have seen his engine run and it is very powerful.

Good info Stu, can we assume you have told CMB & are they going to take steps to correct the issue? Are they standing behind the failures?? Unfortunately not all have access to professional honing equipment or lathes to undercut a liner to drop it in the case. Honestly in my opinion for what racers are paying for these motors they shouldn't have to do this at all. I'm sure you are on top of it & hopefully CMB will have a permanent fix out quickly. B)

 

[Don Ferrette]

Ok I gotta ask-

The guy who asked me about setting up him up with an F hydro and a CMB80RS-H just e-mailed me saying he's been in contact with a CMB dealer who told him that there is no warranty on the motor whatsoever, even if the sleeve gets honed. So we know there seems to be an out of the box issue with the sleeve failing but no warranty?? To those out there who have broken the motors, are you having to pay for replacement parts on a new motor failure?? If not who is standing behind this on parts replacement?? I know Tidewater was pretty good about standing behind legitimate failures so what has changed?? I'm not trying to start any great debate here, just want to be able to give this guy a straight answer. So can someone shed a little light on this?? Stu?? Anybody?? :unsure:

 

[Stuart Barr]

Ok I gotta ask-The guy who asked me about setting up him up with an F hydro and a CMB80RS-H just e-mailed me saying he's been in contact with a CMB dealer who told him that there is no warranty on the motor whatsoever, even if the sleeve gets honed. So we know there seems to be an out of the box issue with the sleeve failing but no warranty?? To those out there who have broken the motors, are you having to pay for replacement parts on a new motor failure?? If not who is standing behind this on parts replacement?? I know Tidewater was pretty good about standing behind legitimate failures so what has changed?? I'm not trying to start any great debate here, just want to be able to give this guy a straight answer. So can someone shed a little light on this?? Stu?? Anybody?? :unsure:

Tidewater and myself knew of the problem with this motor and neither of us warrantied the sleeve breakage. Both Art and myself have talked with CMB about the problem. On every motor that I have sold, I have cautioned buyers about this problem and have offerred a fix (honing) for a price. Because of this problem, the 80 RS price has remained basicly the same for the past two years. For all those that wish to continue to bash CMB, Call Aeromarine Laminates @302-628-3944 and order a less expensive OPS motor. It is great that CMDI is close to producing their marine engine line. Perhaps they maybe able to shed some light on what the cost of their engines might be and the "debate" may be over.