CMB V5 45

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Jim Allen

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Jun 7, 2005
Messages
1,611
Yes Andy. We have found several other head shapes that will produce more HP, but the old enemy of glow plug engines, detonation, rears its ugly head. 

JA
 

shoboat

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Jun 23, 2002
Messages
6,991
Andy and Jim,

This type of head button was a favorite of Jim Wilson and many others who modify

our engines. I never flew airplanes, but it sounds like the Super Tigre X-40 engine was ahead

of its time?

Thanks For Sharing Fellas,

Mark Sholund
 

Jim Allen

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Jun 7, 2005
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1,611
Andy & Mark,

When the two chambers are machined in the correct size & shape to one another, excessive overleaning of the engine produces the results seen in the photos on the right. There is no pitting of the piston or head & the glow plug will not be destroyed. We do not know the reason for this! The ware band remains on the side of the piston & the pistons upper outer edge does not touch the cylinders wall. We have been able to blow the taper out of the top of the cylinder without any scuffing or loss of chrome when over leaning the engine. Running the engine in an over lean condition also produces a very dark area under the piston crown, but there is no death ash. 

Jim Allen

P9080023.JPG
 
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shoboat

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Jun 23, 2002
Messages
6,991
Jim,

Is that a carbon type deposit on the two head buttons on the right?

It looks like the head temperature got really hot? Interesting picture.

Is there a formula for the right height and depth for the bowls? I would

like to try some new head button configurations on one of my friends

engine Dyno. We are trying to get the horsepower over 2 HP and improve

the torque readings higher on this next test session. This is for a 12-on-road 

car engine in one of my 12-Hydros. It looks like you are running quite a bit of 

castor in your fuel?

Thanks For Sharing,

Mark Sholund
 
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Jim Allen

Well-Known Member
Joined
Jun 7, 2005
Messages
1,611
Jim,

Is that a carbon type deposit on the two head buttons on the right?

It looks like the head temperature got really hot? Interesting picture.

Is there a formula for the right height and depth for the bowls? I would

like to try some new head button configurations on one of my friends

engine Dyno. We are trying to get the horsepower over 2 HP and improve

the torque readings higher on this next test session. This is for a 12-on-road 

car engine in one of my 12-Hydros. It looks like you are running quite a bit of 

castor in your fuel?

Thanks For Sharing,

Mark Sholund
We are running the standard fuel everyone must use. It contains 20% degummed castor. Less castor down to 10% doesn't make any more power. PM your address & I'll send a sample head used on the .45 cu in pylon racing engine.

JA
 

Stuart Barr

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Joined
Mar 24, 2005
Messages
1,184
Ok, when is it possible of replace only the drum housing  by cmb hr, the drum valve would be that of the V5
Gilbert,

The V.5 parts will not retro fit to the HR.  Best get a V.5 complete motor.  It is a much better motor.

Stu
 

gilbert galli

Active Member
Joined
Apr 27, 2013
Messages
34
Gilbert,

The V.5 parts will not retro fit to the HR.  Best get a V.5 complete motor.  It is a much better motor. 

Stu
I request information, i have a carbon rocket hydro 7.5 with cmb 45 hr and it is impossible to replace the engine with the v5 because the carb touches the sponson tube, with the v5 must move back the engine



Gilbert
 

Stuart Barr

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Joined
Mar 24, 2005
Messages
1,184
Gilbert,

I see that it is "tight".  Looks like there would be room to move motor back.

Stu
 

Samuel Hagan JR

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Jul 18, 2010
Messages
3,781
I request information, i have a carbon rocket hydro 7.5 with cmb 45 hr and it is impossible to replace the engine with the v5 because the carb touches the sponson tube, with the v5 must move back the engine



Gilbert
Would the RSEvo be a better fit?
 

gilbert galli

Active Member
Joined
Apr 27, 2013
Messages
34
Would the RSEvo be a better fit? 
it is possible to put a cmb v5 or 45 rs evo but it is necessary to work the  news engine mounts even with the use a novarossi 46dd, piston sleeve of hr are used, but I have a trick to regain compression, just do two revolutions with a tube cut in the lubrication groove of the piston, it pushes back the material and you have breaking  engine with four tanks
 

shoboat

Well-Known Member
Joined
Jun 23, 2002
Messages
6,991
Jim,

I sent you a personal message with my address like you requested.

Thanks for helping us all out with this important information on everything you do

with your motors. IW is a wealth of information.

Thanks For Sharing Your Knowledge Jim,

Mark Sholund
 

Rick Doane

Well-Known Member
Joined
Aug 24, 2005
Messages
331
Any sharp edge on the ID of a cylinder bore will cause the chrome to buildup on that edge. Careful removal, before chroming, of those sharp edges with an Exacto knife & brush hone eliminates this problem. 

Jim Allen

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Hello Jim.......from the pics I see,  those heads appear to have closer to 50% squish band ratio than any I have seen posted.  Also, does the rise from the squish have a straight side prior to the radius on the inside?

Regards.......Rick
 

Jim Allen

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Joined
Jun 7, 2005
Messages
1,611
Hi Rick,

The squish area is 50% of the bores area & it is dead flat. The edge of both starting radius points needs to be very sharp. No polishing of any part of the head is ever done. A good turbo plug seal is worth approximately 300 + RPM. We are making both the seat in the head & the plug body.

JA
 
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Jim Allen

Well-Known Member
Joined
Jun 7, 2005
Messages
1,611
Jim,

I sent you a personal message with my address like you requested.

Thanks for helping us all out with this important information on everything you do

with your motors. IW is a wealth of information.

Thanks For Sharing Your Knowledge Jim,

Mark Sholund
Mark,

I'm sending you a brand new, never run head. If you have access to a comparator, I would cut the head in half to measure & see exactly what is machined in the two bowls. Also, look at the turbo plugs seat.

JA
 

shoboat

Well-Known Member
Joined
Jun 23, 2002
Messages
6,991
Jim,

I have access to a really good machine shop now, I will take it down to the owner of the shop

and have him help me with it. I sure appreciate your generosity Jim. I guess I need to start taking

some adult education classes in machining and CNC programing.

Thanks For The Help And Inspiration Jim,

Mark Sholund
 

Jim Allen

Well-Known Member
Joined
Jun 7, 2005
Messages
1,611
No problem giving out valid information which should not be kept a secret. Before anyone can see what our miniature toy engines are really capable of, all those mechanical things that can only be done in a machine shop must be learned & applied. Did you ever get that bottom end roller rod problem solved?

Jim Allen
 
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