1.01 cmb burning holes in pistons

[Tom Foley]

this is what I'm talking about.

http://madmodder.net...ic,2456.75.html

Awesomeness !! Looks like a Mikuni to me !

 

[SayMikey]

Just a thought,anyone ever give any thought to boring a hole in the skirt near the transfer ports to try and spray the bottom of the piston? Much like a cooling jet

 

[Joe Warren]

Tim, yeah there have been a few. But i've only seen a handfull of cases in the past 2-3 years. We run 15-25% nitro in them. We run 30 minute races so the problem comes from fitting enough fuel in to last. I run 25% in my 15cc v boat and my hydro though. We find the bearings are the worse problem

Both bearings? I have had issues with the bearing at the flywheel end.

Change your bearings to a C-3 P-5 And your bearing problems will go away.

 

[Joe Warren]

Buck, I like your realtree readings. But there are Several Settings that are static that we use for tuning. Your head clearence... Do you think it actually is what your read with your Accucheck when it is actually running? Nope..... With the slop of the each end of the rod, and you know there is expansion.... Your flow meter Number is a static number, You dont know pipe pressure number and you have no venturi vacuum yet.... Even your boat set up is Static, Cause you are trying to guess what will happen with another guess as to what the prop lift & Air surface tension will be???? I think we could learn a lot by Readings on Exhaust Header Temps & Pipe Pressure readings at Wide Open Throttle.... It could be as easy as using welders melt stick across the header pipe?? about 3 strikes of different temps and you could know the header temp at operating speed. When you get the header temp up and It is getting plenty of fuel to Run..... it will be FAST!!!!!!!!!

 

[Buckshot]

Buck, I like your realtree readings. But there are Several Settings that are static that we use for tuning. Your head clearence... Do you think it actually is what your read with your Accucheck when it is actually running? Nope..... With the slop of the each end of the rod, and you know there is expansion.... Your flow meter Number is a static number, You dont know pipe pressure number and you have no venturi vacuum yet.... Even your boat set up is Static, Cause you are trying to guess what will happen with another guess as to what the prop lift & Air surface tension will be???? I think we could learn a lot by Readings on Exhaust Header Temps & Pipe Pressure readings at Wide Open Throttle.... It could be as easy as using welders melt stick across the header pipe?? about 3 strikes of different temps and you could know the header temp at operating speed. When you get the header temp up and It is getting plenty of fuel to Run..... it will be FAST!!!!!!!!!

I've got a pile of temp sticks I can send you.......I don't want them any more.

Ain't technology great?

 

[Ian Inverarity]

Change your bearings to a C-3 P-5 And your bearing problems will go away.

Actually I was, but thanks for your input anyway.

 

[dwilfong]

http://www.eagletree...cessories/2.htm :wub:

 

[dwilfong]

Here is the log of the only piston I holed.

and here is the results. 30% Si billet piston.

So at what temp dose a piston go away?

At what temp did it make the best power?

You can learn allot from going to far.

 

[Joe Warren]

Buck, I like your realtree readings. But there are Several Settings that are static that we use for tuning. Your head clearence... Do you think it actually is what your read with your Accucheck when it is actually running? Nope..... With the slop of the each end of the rod, and you know there is expansion.... Your flow meter Number is a static number, You dont know pipe pressure number and you have no venturi vacuum yet.... Even your boat set up is Static, Cause you are trying to guess what will happen with another guess as to what the prop lift & Air surface tension will be???? I think we could learn a lot by Readings on Exhaust Header Temps & Pipe Pressure readings at Wide Open Throttle.... It could be as easy as using welders melt stick across the header pipe?? about 3 strikes of different temps and you could know the header temp at operating speed. When you get the header temp up and It is getting plenty of fuel to Run..... it will be FAST!!!!!!!!!

I've got a pile of temp sticks I can send you.......I don't want them any more.

Ain't technology great?

I just put my check book in the radio box, Cause it is the 2ndt thing you will need racing twins & I dont want to be looking for it.

 

[Joe Warren]

This Topic has a Hole Burned in it......... :wacko:

 

[Tim_Duggan]

Here is the log of the only piston I holed.

and here is the results. 30% Si billet piston.

So at what temp dose a piston go away?

At what temp did it make the best power?

You can learn allot from going to far.

Wow - the temp really rocketed up fast on that run and didn't plateau until the piston cried enough!!!!!!!

It was making consistent rpm around 24k with the temps in or around 200 degrees until it went way too hot.

the way that temp was climbing so fast I doubt the piston would have survived unscathed anyway even if it hadn't blown a hole.

 

[Tom Foley]

Looks like a textbook example of runaway lean ! I guess 280 deg is too hot , **** !

 

[julianconde]

I agree with tom that engine was screaming for mercy LOL Way lean

 

[dwilfong]

Yes that was with the pipe Scott made for me. I got caught up in the moment and for got to hit the button soon enough.

I was pushing the 3rd channel button as hard as I could and could not feed it enough.

Ran out of adjustment. when I checked the needle with the BM meter it was at 20.

Gabriel's horn blew good that day.

 

[dwilfong]

Yes that was with the pipe Scott made for me. I got caught up in the moment and for got to hit the button soon enough.

I was pushing the 3rd channel button as hard as I could and could not feed it enough.

This all took place in less than 20 seconds 1 1/2 laps around the pond let go at the end of the back stretch.

Ran out of adjustment. when I checked the needle with the BM meter it was at 20.

Gabriel's horn blew good that day.

It did show me what I was looking for a ABC 2818 will be 100mph racing prop at 2600RPMs

Now to get the eng to pull it at 26000 and live.

I will find out with this new setup in the next two weeks.

 

[Bob Morton]

Yes that was with the pipe Scott made for me. I got caught up in the moment and for got to hit the button soon enough.

I was pushing the 3rd channel button as hard as I could and could not feed it enough.

This all took place in less than 20 seconds 1 1/2 laps around the pond let go at the end of the back stretch.

Ran out of adjustment. when I checked the needle with the BM meter it was at 20.

Gabriel's horn blew good that day.

It did show me what I was looking for a ABC 2818 will be 100mph racing prop at 2600RPMs

Now to get the eng to pull it at 26000 and live.

I will find out with this new setup in the next two weeks.

Hi Dave,

Good Data at 20 on the Boris Meter. The 90 engines are so rich they bearley run?

Nails.

 

[dwilfong]

Yes that was with the pipe Scott made for me. I got caught up in the moment and for got to hit the button soon enough.

I was pushing the 3rd channel button as hard as I could and could not feed it enough.

This all took place in less than 20 seconds 1 1/2 laps around the pond let go at the end of the back stretch.

Ran out of adjustment. when I checked the needle with the BM meter it was at 20.

Gabriel's horn blew good that day.

It did show me what I was looking for a ABC 2818 will be 100mph racing prop at 2600RPMs

Now to get the eng to pull it at 26000 and live.

I will find out with this new setup in the next two weeks.

Hi Dave,

Good Data at 20 on the Boris Meter. The 90 engines are so rich they bearley run?

Nails.

Believe me this is not typical. The pipe I was using will suck the guts right out of a 1.01.

Gave that pipe to Jerry at the last race as a present.

Hope he can make good use of it.

To much for me to handle.

 

[dr gary turner]

Just a thought,anyone ever give any thought to boring a hole in the skirt near the transfer ports to try and spray the bottom of the piston? Much like a cooling jet

Mike since the 101 came out we have been cutting a slot and series of holes in the slot about 1/4 inch below the exhaust port to cool the exhaust side of the piston and prevent sticking and it works.

I had a thought of doing something on the transfer ports just below the top of the port to spray fuel across the piston. Again since the brass head button's we have not burned any holes.

 

[Tom Foley]

Just a thought,anyone ever give any thought to boring a hole in the skirt near the transfer ports to try and spray the bottom of the piston? Much like a cooling jet

Mike since the 101 came out we have been cutting a slot and series of holes in the slot about 1/4 inch below the exhaust port to cool the exhaust side of the piston and prevent sticking and it works.

I had a thought of doing something on the transfer ports just below the top of the port to spray fuel across the piston. Again since the brass head button's we have not burned any holes.

What were you running in Charleston when you burned one down ? I switched to a brass button that measured .85 CC , flat top piston and burned right away , too lean . Brass , Aluminum , I don't think it matters but too lean REALLY matters!

 

[dwilfong]

Just a thought,anyone ever give any thought to boring a hole in the skirt near the transfer ports to try and spray the bottom of the piston? Much like a cooling jet

Mike since the 101 came out we have been cutting a slot and series of holes in the slot about 1/4 inch below the exhaust port to cool the exhaust side of the piston and prevent sticking and it works.

I had a thought of doing something on the transfer ports just below the top of the port to spray fuel across the piston. Again since the brass head button's we have not burned any holes.

What were you running in Charleston when you burned one down ? I switched to a brass button that measured .85 CC , flat top piston and burned right away , too lean . Brass , Aluminum , I don't think it matters but too lean REALLY matters!

You are most definitely right lean is lean brass or not. CR dose not matter head clearance dose not matter lean is lean.

Lean is what is holing pistons. no more no less.

Now what you do to get the power you need and not run lean that is a whole different story.

Like I said the mods I do are just a band aid to help keep the eng alive.

The mods I had done did not prevent it.