Break in new cmb v5 best way!

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douglong

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Jul 21, 2015
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I'm ready to break in my new cmb v5. What is the best way to break in a new engine, percentage of nitro, what temp should I keep the engine at while breaking in?
Thanks
 
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I'm ready to break in my new cbm v5. What is the best way to break in a new engine, percentage of nitro, what temp should I keep the engine at while breaking in?
Thanks
Run it in the boat, on the water at a rich needle.
Run conservatively with occasional 1 lap full throttle runs.
Do this running a couple of tanks of fuel through the engine.
What I do, works for me.
A good friend of mine and one of the fastest guys on the water, says, break them in the way yer gonna race em!
I like to go with my routine.
 
Run it in the boat, on the water at a rich needle.
Run conservatively with occasional 1 lap full throttle runs.
Do this running a couple of tanks of fuel through the engine.
What I do, works for me.
A good friend of mine and one of the fastest guys on the water, says, break them in the way yer gonna race em!
I like to go with my routine.
Any suggestions on percentage of nitro what should yhe engine temp be
 
First step I would make sure you disassemble the motor and clean any burs/flashing in the ports of the liner, and make sure there is nothing there that shouldn't be. When reassembling I like to always put a drop of Castor or oil in any of the threaded holes everytime I put the motor back together. I would then set your head clearance to what you prefer, then start your break in method. Percentage of nitro is a personal preference I just like to make sure that the fuel I am running has 18% oil but that is just me. What boat are you going to be running it in?
 
First step I would make sure you disassemble the motor and clean any burs/flashing in the ports of the liner, and make sure there is nothing there that shouldn't be. When reassembling I like to always put a drop of Castor or oil in any of the threaded holes everytime I put the motor back together. I would then set your head clearance to what you prefer, then start your break in method. Percentage of nitro is a personal preference I just like to make sure that the fuel I am running has 18% oil but that is just me. What boat are you going to be running it in?
.45 crapshooter
 
Just cause I dont like fighting a new motor start at the lake, I will start it up at home using my normal race fuel. I run one tank thru it on the bench at high idle. I heat cycle the motor using my third channel. I lean it out and get the temps up, then fatten it while still running. I can watch the temps cool on the head. Then rinse and repeat until all the fuel is gone. Take to lake and run it.
Mike
 
I've been running extra oil for the first few gallons and I find it helps get the piston/sleeve in better shape long term. I usually run 60% with 15% oil (10 Klotz KL200/5 Blendzall castor) but bump it up to 21% (14/7) for the first gallon and 18% (12/6) for the second. Run it rich as mentioned but pinch the water down to still get some heat, using your flowmeter for this is good.

Another trick I got from Neil Lickford (CL speed flyer, worked with Henry Nelson) is to disassemble the engine after each gallon and very gently smooth out the scuffs on the piston with a green extra fine craytex stick. When it's done right it should look like this.

225841-CMB67a.jpg
 
Terry, do you then put it in the dishwasher on HOT or lightly boil the piston to get the grit out and off the piston?

I have Dimond lapping and I am hear to tell ya.. you have to SUPER CLEAN the parts after.. or.. risk damage (I have ALWAYS got them clean)

Grim
 
Terry, do you then put it in the dishwasher on HOT or lightly boil the piston to get the grit out and off the piston?

I have Dimond lapping and I am hear to tell ya.. you have to SUPER CLEAN the parts after.. or.. risk damage (I have ALWAYS got them clean)

Grim

I just hit them with Brakleen, the grit is so fine in the rubber matrix and you use it so gently that I don't think it transfers anything to the aluminum, the stick just gets a little darker.

The cone shaped points are also good for going around the ports to blend the chrome in slightly after getting the gobs off with a diamond file.

https://www.cratex.com/Products/Rubberized-Abrasives/Blocks-and-Sticks/Square-Sticks
These guys are good for small quantities:

https://www.moldshoptools.com/

CMB 45 - bad chrome.jpg
 
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Wow. That flashing is bad. Its a shame to spend the money we do and recieve an engine like that.
I just hit them with Brakleen, the grit is so fine in the rubber matrix and you use it so gently that I don't think it transfers anything to the aluminum, the stick just gets a little darker.

The cone shaped points are also good for going around the ports to blend the chrome in slightly after getting the gobs off with a diamond file.

https://www.cratex.com/Products/Rubberized-Abrasives/Blocks-and-Sticks/Square-Sticks
These guys are good for small quantities:

https://www.moldshoptools.com/

View attachment 320436
 
I just hit them with Brakleen, the grit is so fine in the rubber matrix and you use it so gently that I don't think it transfers anything to the aluminum, the stick just gets a little darker.

The cone shaped points are also good for going around the ports to blend the chrome in slightly after getting the gobs off with a diamond file.

https://www.cratex.com/Products/Rubberized-Abrasives/Blocks-and-Sticks/Square-Sticks
These guys are good for small quantities:

https://www.moldshoptools.com/

View attachment 320436
Yikes!!
 
Never use Dimond lapping.It gets imbedded in the piston and you will never get it out.After use a microscope and look at the piston it is still there after cleaning it in a Ultrasonic cleaner.
 
Diamond and other hard particles like Silicon carbide grit kill bearings very quickly. As mentioned above it's really difficult to remove all and it's the tiny micron levels that do the most damage to the bearings.
 
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