CMB Holed piston Fix

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theres a simple solution to this problem buy new parts. i understand the hobbie is very expesive and this economy is not the best right now. this is a practice i would never do..

julian
 
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if I had a 101 id do it in a heartbeat. More meat on the piston top will make that motor live a good long life. I cant count the holed pistons that Ive seen and at $200 a copy id glady do this fix
 
people do what they can afford. A wise man Told me dont get into a particular class you cant afford .. ;) me new parts everytime.. i might sell my burned pistons to people that dont want to buy new ones and have them fixed by foley. lol by the way Tom good work..
 
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A holed Piston is the results of Low Fuel Pressure or an air leak ( header rubber)( or a cracked fuel line) Wrong Pipe or Pipe length, OR the engine is OVER COOLED. Leaning the needle to make Engine Heat is a BAD HABIT!!!!! You need to know a Base line flow number for the Needle setting and the OPERATING TEMP of your Engine cooling head!!!!!!! A Holed Piston in a RS101 is the END RESULT of a Different Problem. IF YOU DO NOT FIND THE PROBLEM?? IT WILL REPEAT ITSELF.. Large Pipe Presure fitting, Large Fuel tubing,Clean Tanks,Clean Fuel Filters, Clean Needles.... Just the begining.
 
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To add to what Joe said breaking a water line while running a heat and not seing it on time will result in a hole in the piston.. Happen too me already

Julian
 
Can you weld a Hole in My WALLET?? I can burn a Hole in your repaired piston if the real problem is not corrected!! Are you going back and correcting the Bob weight of the Piston after welding?? Or just SLAM IT IN...... and GO!!!!!
 
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Yeah Joe Im trying to get Julian to take a plunge into fe He likes your nitro motors too much right now :D .

Hugh
 
Can you weld a Hole in My WALLET?? I can burn a Hole in your repaired piston if the real problem is not corrected!! Are you going back and correcting the Bob weight of the Piston after welding?? Or just SLAM IT IN...... and GO!!!!!

Joe , I think it's widely accepted that the problem that caused it needs to be fixed as you have mentioned . This proceedure does help those who have lots of time in sleeve work get back on the water and run , as well as those who don't have an ammo box full of new P./S sets . Have you ever bored one hole in an outboard instead of doing all six ? It works, and you'd never know only one hole was .015 over . :D
 
Tom I have Repaired Gas/Diesel engines up to 1000 CID & Repaired Auto and Industrial transmisions for 30 plus years. I have seem some Bull sxit!!!!! Only point i was making is the Problem will Return.... IF THE REAL PROBLEM IS NOT FOUND!!!!! Tuning a Boat by ear with the third channel knob in your hand can be Expensive. For BIG BLOCK ENGINES You need a base line needle setting. And Know the operating temp of the engine. You would be surprised how many times boaters Squeeze the fuel completely off just to get the engine to come to Operating temp. You Cannot fix the entire boat with the THIRD CHANNEL or Argon & Alum rod
 
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Tom I have Repaired Gas/Diesel engines up to 800 HP at 1000 CID & Repaired Auto and Industrial transmisions for 30 plus years. I have seem some Bull sxit!!!!! Only point i was making is the Problem will Return.... IF THE REAL PROBLEM IS NOT FOUND!!!!! Tuning a Boat by ear with the third channel knob in your hand can be Expensive. For BIG BLOCK ENGINES You need a base line needle setting. And Know the operating temp of the engine. You would be surprised how many times boaters Squeeze the fuel completely off just to get the engine to come to Operating temp. You Cannot fix the entire boat with the THIRD CHANNEL
buy a VAC and be done with it!
 
Or you could have me build some billet pistons........another option.
I did but I am hell on them.

But It did go over 100MPH in race trim when it happened.

Still trying to get a handle on the pipe you made me.

It is a real beast the power is over the top still need more prop to keep it loaded.

Don't worry I WILL get It tuned for the fall nats.

Less nitro and more Castor to control the cylinder temp.

O by the way I need a few more to test. :D

David
 
LOL....wow David u burned a hole that piston? I think I made the piston crown .100 thick.Sounds like your making some good HP though!
 
I did some checking on the crown thickness after this happened. the stock piston is .110 and the ones you made me are .130

That is also taking into account the compression hight is .020 taller on the ones you made me.

Well dumb a$$ cut .030 off the top to get the timing numbers right. :rolleyes:

This left .100 when it was all said and done.

If you look at the piston it was not melted like the stock ones did. it had no sag in it just punched a piece out of it.

That pipe is making killer cylinder pressure.

Think I will not need 55% nitro to make power will try 40% and take it easy on the equipment.

When you get back at it give me a call need some more with a longer skirt and thicker crowns.

Jacked the sleeve on the next build .020 to keep all the meat on the crown.

David
 
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