1.01 cmb burning holes in pistons

[julianconde]

i ran torco 60%, otto 60%, bullard 50 % grim racer 50% the only difference in the Oval trials was .15-.35. now you do have to burn the fuel and i agree. now the difference from running zoom carbs to regular carbs are way different on the 101RS motors from the testing i have done so far in heat racing or record trials so chuck i would have to disagree go to a record trials try different carbs then see what the difference is..

when i ran my Twin at the 1/4 mile oval with the regular steve wood mod cmb carbs the fastest i could get the boat was 17.10 2 lap. two weeks later i used my 80 zoom carbs and went down to 16.67 with out making a change other than the carburator you tell me the difference ??? You have to burn fuel to make more power..

the transition from half to full throttle is fast my motors do not hesitate they pop right on the pipe thats a big advantage when you get off the trottle on the start and punch it.

Buck by the time i add the extra lubricant to my 60% fuel that would not be the number any more i run 22-24% oil content.

the mods on my motors you will have to talk to Joe W. the only time i have burned a hole in a piston is because my water line broke and another piston the pin boss broke. i ran almost 35 gallons thru my set of 101RS in 2011/2012 and have never had a issue with them.

 

[SayMikey]

when i ran my Twin at the 1/4 mile oval with the regular steve wood mod cmb carbs the fastest i could get the boat was 17.10 2 lap. two weeks later i used my 80 zoom carbs and went down to 16.67 with out making a change other than the carburator you tell me the difference Your larger carb bore leaned the motors!

 

[Don Ferrette]

when i ran my Twin at the 1/4 mile oval with the regular steve wood mod cmb carbs the fastest i could get the boat was 17.10 2 lap. two weeks later i used my 80 zoom carbs and went down to 16.67 with out making a change other than the carburator you tell me the difference ??? You have to burn fuel to make more power.

Unless you ran the different carbs back to back on the same day saying just the carbs made all the difference is unsubstantiated and mere speculation. You're basically talking barely over two tenth's of a second per lap and I've seen air density changes in a single day make a much bigger impact than that in regards to speeds and lap times. When Finch busted the E hydro SAW record he went 116+ with a STONE STOCK right down to the carb green head 67. As others have mentioned correct temps, fuel flow, head volume, spraybar AND pipe stinger i.d's are the ticket on these 101's as I've found out now for myself.

 

[Joe Warren]

At 80% efficiency a 1.01 needs 12 CFM to run at 26000 rpm.

Charles how much did you say that zoom .560 carb flowed 6 CFM?

You need a minimum of a .650 carb to feed this eng.

Heck a MAC .84 has a .550 on it.

So a .550 will feed a 1.01?

maybe on %20 nitro it will and we are trying to put what %60 thew it.

More nitro needs more "AIR" not the same amount as %20 to burn. So we go lean.

This eng was not made to burn high nitro. It was made to European racing specks.

Make it as hot as you want and the bowl as big as you want it will still burn up when pushed to the limits.

Hopefully the new eng will address these concerns.

As for now just run it rich and hot and keep your finger off the needle. If it dose not look like a steam eng out the ex it Will go by by.

When the smoke disappears so will the piston.

David

Nitro is a Oxygen Bearing Fuel. YOU Dont need a 1100 Holly to feed a 1 inch Piston. When your doing your Math CFM needed per CID X RPM? Dont Forget... NITRO IS A OXYGEN BEARING FUEL Steve Odonnell taught us long ago that when there is No Air?? ADD MORE NITRO. When you UP the Nitro percentage you can Produce More Air within the fuel & you dont have to rely on current weather conditions. Someone ask is there a difference on 50-60-65 fuel. YES.....Power to the Prop is the Diffference. But you must be in a Heat Operating Range 160-180 to Light the Nitro. if you are 125 degrees or less you will not see any difference (cause your not lighting the nitro anyway). many dont know the engine operating temps???? You must know in order to go fast. We travel to every race. I have no commom test lake. So the water is different at every race site.... & where did Steve Wood ...... Go?

 

[Joe Warren]

when i ran my Twin at the 1/4 mile oval with the regular steve wood mod cmb carbs the fastest i could get the boat was 17.10 2 lap. two weeks later i used my 80 zoom carbs and went down to 16.67 with out making a change other than the carburator you tell me the difference ??? You have to burn fuel to make more power.

Unless you ran the different carbs back to back on the same day saying just the carbs made all the difference is unsubstantiated and mere speculation. You're basically talking barely over two tenth's of a second per lap and I've seen air density changes in a single day make a much bigger impact than that in regards to speeds and lap times. When Finch busted the E hydro SAW record he went 116+ with a STONE STOCK right down to the carb green head 67. As others have mentioned correct temps, fuel flow, head volume, spraybar AND pipe stinger i.d's are the ticket on these 101's as I've found out now for myself.

BINGO. .. Correct Stinger Size = Correct Fuel Pressure #1 problem in any large CID engine @ high RPM.. Spray Bar ID Corrected = Less Restriction to Flow & Less Friction Loss.

 

[BigChuck]

Well, I have the very oppsite of what Jul said. And he was there when it happened..........."Oh, he was busy" B)

Very noticeable difference.............but you have to Burn the nitro,if not you do not see the difference.

Chuck,

WHAT kind of difference?? What kind of advantage??

Buck...We compared it to engaging the second MSD Box on the Funny Car. I was running...but I did not have "The GO!!!"

 

[sbowden21]

Good fuel, proper cooling, open the head button volume = no holes for 3 years on 3 different motors

 

[Joe Warren]

Fuel,

I did 10 pistons including billetpistons until I found out run the engine much hotter and richer.

Paul when we ran fixed needles in Twins, If I was helping someone else with there boat I want to drive it about 3 laps. What i was wanting to know is if the needle would come to the lean side about 3-4 clicks by heating up OR if it went about 3-4 clicks the Other Way & What the prop load was... This would tell you if the Water was Grabbing the Engines (Cold Operating Condition). We always threw in hot and wanted to see good speed down the back shut. But if things began to change after 1 - 1 1/2 laps you knew the water was dragging down the engine temps. Now at this time If you could reach out there where the boat was..... you could make a needle change to heat it all back up. BUT This does not say that you have enough fuel to feed it all when the piston speed comes back up????????

 

[steve wood]

Unless you ran the different carbs back to back on the same day saying just the carbs made all the difference is unsubstantiated and mere speculation. You're basically talking barely over two tenth's of a second per lap and I've seen air density changes in a single day make a much bigger impact than that in regards to speeds and lap times.

i agree!

 

[Joe Warren]

As this conversation continues? a way to check your existing fuel system is set up properly? After you have got onto the lake and made a lap or two your fuel system should flow enough fuel to richen the boat up on a FAT Needle at High piston speed. If it cannot not? you better start to look at it. This means you cannot maintain a high piston speed & fatten the engine up too. This is going to be a Problem when you try to Run Wide Open Throttle Loaded with prop.... If you are Miling Rich and Happy And an medium increase in throttle position the engine seems to COME INTO ITS OWN NEEDLE?? STOP STOP !! ITS RUNNING OUT OF FUEL........... THIS is a Perfect example of its fixed to Burn Itself Up. This is a Must Test before you even think about leaning it down. A topic we had eariler in the week was about Reading the Plug........ I HAVE NEVER SEEN A ENGINE EAT A PISTON THAT WAS GIVING HAPPY PLUG READINGS. If this does Happen? Look for what changed?? Cracked fuel inlet line No pipe pressure or Cracked & Burnt header orings..... Normally the Glow plug would have been already Warning the driver that something was wrong with the boat!!

 

[Joe Warren]

Unless you ran the different carbs back to back on the same day saying just the carbs made all the difference is unsubstantiated and mere speculation. You're basically talking barely over two tenth's of a second per lap and I've seen air density changes in a single day make a much bigger impact than that in regards to speeds and lap times.

i agree!

This is a Bigger problem if you are running coastal areas. When the Wind blows the air off the Water - Bay area it is full of Oxygen 100 plus on a density meter. If the Wind Changes direction and the Air is now coming off the land?? It has much less air in it. if you had a Air density meter on the table it would be Swinging Wildly. I pay attention to a density meter so if the Power is Down I know why & I dont make the mistake is pinching the balls off the engines that day. It effects everyone else you are racing they will have the same problems as you on a BAD AIR day....P.S. in Charleston SC a couple of years ago we seen the wind blowing off the ocean most of the week & had 120 plus air on the density meter. It is Now time Gentlemen to get into the Prop Box & Find more prop. Or find your rusty prop pliers. This GOOD AIR vs BAD AIR can change much quicker the Larger the body of water you are Either On..... or Very near.

 

[dwilfong]

i have 80 zoom carbs on my Twin 101RS and there .550 bore i don't have a problem feeding fuel to the motors. i run 60% i have run 50% and there is not difference really by the time we add Klotz lubricant to our fuel the of nitro drops. the problem is making heat and not leaning on the needle people are trying to Mod the hell out of the engine that's the problem too. i take away and add water as needed depending on the weather and i hardly have to needle down my engine

to me with what we do to our engines im pretty happy at the moment. people are trying to mod the engines like there 21's thats the problem 100MPH heat race boat is not needed to win the race.

Julian

that carb is only .500

 

[steve wood]

100MPH heat race boat is not needed to win the race.

i know that the fastest boat/car/horse, does not always win,but just ask anyone what they would rather have,the slowest or the fastest.hey take a pole guys.do you want the fastest boat or the slowest boat? i know where my money's at

 

[julianconde]

my twins are slow ill take those

 

[dwilfong]

You know I have run many eng lean WAY lean. took plugs and that was it.

So the 1.01 -.91RS run lean and put holes in the piston.

VAC .91 any holed pistons? None that I have heard of.

So lean is all there is to it ?

So do a test for those that run both .

Run your VAC .91 till it blowes the plug.

Let me know if it ever holes a piston?

Don't think so.

 

[Joe Warren]

You know I have run many eng lean WAY lean. took plugs and that was it.

So the 1.01 -.91RS run lean and put holes in the piston.

VAC .91 any holed pistons? None that I have heard of.

So lean is all there is to it ?

So do a test for those that run both .

Run your VAC .91 till it blowes the plug.

Let me know if it ever holes a piston?

Don't think so.

Not a Good Comparison...... Compare a CMB EVO 100 Sleeve to a CMB RS101 sleeve. I will say NO more. When Jerry crowther Originally installed a EVo 100 Sleeve into the RS91 long stroke block there seemed to be No problems......

 

[dwilfong]

You know I have run many eng lean WAY lean. took plugs and that was it.

So the 1.01 -.91RS run lean and put holes in the piston.

VAC .91 any holed pistons? None that I have heard of.

So lean is all there is to it ?

So do a test for those that run both .

Run your VAC .91 till it blowes the plug.

Let me know if it ever holes a piston?

Don't think so.

Not a Good Comparison...... Compare a CMB EVO 100 Sleeve to a CMB RS101 sleeve. I will say NO more. When Jerry crowther Originally installed a EVo 100 Sleeve into the RS91 long stroke block there seemed to be No problems......

It is a very good comparison .91 to .91.

So what makes it not a good compairison?

Same boat same fuel system same setup. Bet you can't hole a VAC.91!

 

[Joe Warren]

You know I have run many eng lean WAY lean. took plugs and that was it.

So the 1.01 -.91RS run lean and put holes in the piston.

VAC .91 any holed pistons? None that I have heard of.

So lean is all there is to it ?

So do a test for those that run both .

Run your VAC .91 till it blowes the plug.

Let me know if it ever holes a piston?

Don't think so.

Not a Good Comparison...... Compare a CMB EVO 100 Sleeve to a CMB RS101 sleeve. I will say NO more. When Jerry crowther Originally installed a EVo 100 Sleeve into the RS91 long stroke block there seemed to be No problems......

It is a very good comparison .91 to .91.

So what makes it not a good compairison?

Same boat same fuel system same setup. Bet you can't hole a VAC.91!

David.... do you know where the 1st RS101 came from? It was jerry Crowther cutting down the OD of the EVO 100 sleeve to install into a AAC Long stroke RS91. Now the RS91 had the longer stroke crank But a AAC piston liner that did not sale well becuase of the AAC liner. They ran hard but could not keep the fit long. jerry set many records with them. Art mcmeans seen quickly that he could take low timed EVO piston liners out of stock and put them into a RS91 assemblies and make some of the the 1st generation ABC piston liner RS101s. Later on CMB elected to build the engine at the factory and sell them.... the 1st thing they needed was a NEW high timed LINER How many of CMB engines are T ported? & why are they T ported. We know the RS101 is NOT..........

 

[julianconde]

david i think what he meant a better comparison is the CMB 100 and the CMB 101RS thats what the thread was about. one engine never had a issue the other engine bad pin boss and hole in pistons..

 

[Joe Warren]

david i think what he meant a better comparison is the CMB 100 and the CMB 101RS thats what the thread was about. one engine never had a issue the other engine bad pin boss and hole in pistons..

Correct the Rs101 used the same parts as the EVO 100... it how we got to where we are at witht the RS101. the VAc is a entire diff generation of engine.