Early Gold head CMB 80's dual plug heads.

[Daniel's Racing]

I just bought a never run TWIN .80 nitro Whiplash with a pair of these in it. They are brand new stock CMB dual plug gold head .80's but never having owned these or heard much about them I would appreciate any info you could share.

They are stock.

Nitro percentage I should try. Not trying to set records. Prefer whatever would be best suited for dependability and longevity of these engines I have heard aren't all that great.

Are they just grenades waiting to blow? Should I plan on a new pair of current engines. Do the new .67's or .80's(if they still have those) still have same bolt pattern and crank centerline relationships so they would bolt right in place of these?

I am also redoing the entire boat and have a few other questions.

I will be running Prather 265's on them and like to know if that is about the right diameter for these engines and if I have to swap to two new .67's or .80's(does CMB still have a .80) will I ever need a larger diameter than these. The reason I ask is related to this next question.

How much spacing between the prop tips is best.

Moved the rudder already and beefed up the transom and tore out the engines, driveline, servos and mounts and rebuilding.

 

[Danny King]

Daniel if you bring it out to the lake this Sunday I will give you a bunch of advice or ideas. I was one of the guys running a seaducer last week and looked at that boat. It just needs some things.

 

[Daniel's Racing]

Daniel,

Thanks for the offer. Appreciate it.

Kinda have to get some questions answered before then. I am building it now and the struts are going on soon. Well just as soon as the termite tent is off the house Wednesday.

The boat is stripped bare. I need to get some advice on drive spacing as that is going to get done as soon as I get some other opinions on spacing along with the questions I asked. Are 265's about the largest diameter any current .67 or .80 would run. I need to find this out before I mount the struts because I don't plan to relocate them if I will in the future need more diameter for these .80's or new current model .67-.80's .

Someone said almost make the props touch but not sure how critical that is.

Then any info on these engines. I have run nitro for many years just wanted to know what to expect from these. Heard they aren't one of CMB's most successful engines. I have had several CMB 101 powered boats and those are monsters and more dependable than a gas engine.

 

[Bob Morton]

Good Morning Daniel,

You will get lots of differant opions. So you can sort thru them.

I have a pair of those motors, they are very dependable, they are twenty years old and run like new. Ten thousand head clearance.

The center of the props are 3 5/8 of and inch that's on a rigger. Your 265 are ok. Use them to get started. Try later to get a good set of 1667. 6.0 pitch. Set the pipes at 12 inches. The carbs have a high speed needle and a low speed needle. Open the cabs half open

Set the low needle to two full turns out. They run rich and will idle nice. You might have to adjust the so they run the same speed.

Take you flow meter and open the carbs up all the way set them at 38. Mc 9 plugs pull the first two coils down. Only need to light

one plug. Go to Batteries Plus and get a 2 volt 5.0 AH CELL. Sealed -lead rechargeable battery. Use for you glow driver.

Blow out the motors before starting. This works for my twin glow plug motors. You can run 30% nitro 20% oil to get stared and later

move up to 50% nirto and 20%oil. I get my fuel from Otto.

Nails

 

[seaducerpete]

Talk to steve wood he Is on here he had there. Cmb gold head 80 running 90 in a rigger you might have steve set the disk clearance if it isn't all ready done pm steve he is on here trust.me he can make these puppy's scream

 

[Buckshot]

Some generations of the Gold head .67/.80's had issues with wrist pins sticking in the rods. Some needed the small end of the rods honed for clearance. Scratch that, It was the Gold head Evo .67/.80's that had the wrist pin issues NOT the version you have. The motors you have will probably be able to use the current Green head HR parts as they are the same style motor. Current .80 HR's are **** fine motors!

Pretty cool looking, does the standard Whip cowling fit?

I'd like to see the motor mount set up.

 

[steve wood]

Talk to steve wood he Is on here he had there. Cmb gold head 80 running 90 in a rigger you might have steve set the disk clearance if it isn't all ready done pm steve he is on here trust.me he can make these puppy's scream

wrong motor pete.that was an evo 67,this is the pre green head,gold head 80.never had one of these

 

[steve wood]

the purple head 67 has a different bore and stroke than the current green head. i think the 80 gold is probably different also

 

[raceready]

HI' I do believe those motors are cam version,

I have the 67 version.

good luck, cool looking boat.

chris

 

[Don Ferrette]

I've run those early gold heads, here's what I would do for starters if it were me-

1- dump the twin plug head buttons, get Steve Wood to make up some single plug ones for you.

2- you're gonna need bigger fuel tanks, 16-18 oz minimum more would be even better.

3- 265's aren't good hydro props, H48's or 1667's cut down to 64mm @ 5.7".

4- those pipes are very restrictive, upgrade to the current CMB black muffled pipe and definitely mount the rear in a rubber isolator style mount, start at 11 3/4" to 12" from plug centerline to weld and work your way in.

5- there is no low end on those carbs, set the motors fairly rich to start with, do you have a flow meter?

6- those early gold heads run well on 50%, keep the oil at least 18%.

 

[Daniel's Racing]

Thanks for your replies Danny, Bob, Bill, Steve, Chris, Pete and Don

Very much appreciate the information you all have given.

 

[allenrichards1]

I can't believe you pulled the trigger, Daniel!! .....I've got a new Seaducer that Danny is putting the finishing touches on.....more Nitro boats at the lake, the better....

 

[dwilfong]

You going to race that in X hydro here in FL?

 

[Daniel's Racing]

Yah I don't know what I was thinking. I was just out looking at it and it's hard not to picture a brand new CMB 101RS in there instead of going with these twin .80's

I got a tough decision to make right soon. Once it goes together as a twin that's what it is always gonna be. Just thinking I would run it more and get more enjoyment out of it that way and performance would be about the same.

But man I love the sound.of a twin getting it on.

 

[seaducerpete]

If you go with th101 wait until stu gets the new design in stock then You will have the latest greatest