head button material

[dwilfong]

I know this has bin talked about before but would like to post some new stuff here.

And also try and consolidate the info for every one on one post.

I was talking head buttons with a few buddy's in the club to night and the ceramic head button popped in to the mix.

Hard as it can get for a material and no heat transfer in the motor case.

But my thought is will it burn high nitro with no heat in the button?

will the boundary layer that is present in a metallic material be lost resulting in a more complete burn?

Would you be able to run the eng with no water just the cooling from a richer mixture?

David

 

[jaxracer]

What I've come to understand is that you want the head as hot as possible to burn as much nitro as possible. That's why we restrict water lines or eliminate them to make the engine as hot as possible to burn all of the nitro in the cylinder.

Ideally, I'd only want the head itself hot, while doing my best to keep the rest of the case and internals from the exhaust port close back as cold as possible. A cold case, like the concept of cold air vs. hot air, means more air and fuel compacted into the engine per cubic inch.

More fuel, more heat, more burn, more power.

What I would want to do is make a head button that conducts heat rapidly, but then put a buffer, like a ceramic shim, between it and the rest of the engine. That way the head can build a ton of heat without superheating the case. I'd even like to explore water cooling the case and the carb itself to assist with keeping it cool to allow for more fuel and air to enter the engine.

I'm obviously no expert on the subject but that is what makes sense to me.

-Mitch

 

[mark ham]

what about titanium?

 

[Carl Van Houten]

Hey guys,

A few years ago, my buddy Mike Rushing went through the same process. He had some head buttons ceramic coated and ran them thinking he would be able to get a tighter needle without the Pre-det issues . The problem he ran into was the ceramic would flake off and trash the engine. He went through quite a few head buttons and engines before he decided to go back to his standard head design. If you could find someone that could figure out how to get the ceramic to stay on, you may have something but be ready to trash a few engines to find out.

-Carl

 

[dwilfong]

I was thinking of making the button out of ductile iron and heating in the kiln then powder coating it like the way thy make bath tubs.

Also make the whole button out of ceramic.

David

 

[Norm Doerr]

I can tell you that the case is VERY cool under load during operation. I have grabbed the case with an engine running on Marty's dyno many times and it is COLD.. this is running in June in FL... also the intake bell started fogging up with moisture and was significantly colder than the thermo coupler reading in the exhaust and almost as noisy as the exhaust.

Just sayin'

I am not sure the cost an effort of dong ceramic would give you that much of a trade off regarding gains... The good old, cost,effort/gains ratio... With as many times we think of new things to do headbuttons it could get crazy....

 

[lohring]

These days very high strength ceramics are available. It would still need rethinking of the head design since things like threads and clamping systems can cause very high local stresses that start cracks in brittle materials. Still, I think in small engines the whole head button could be made from something like zirconium dioxide. The success of silicon nitride bearings is an indication of the possibilities. The very low heat conductivity would reduce losses and probably make water cooling unnecessary. A matching piston and liner might be needed. Conventional wrist pins would need to be large to reduce stresses. A ball system might work better. Since machining is often with diamond grinding. parts need to be close to finished size. Still, dental crowns are ground from solid ceramic blocks.

Lohring Miller

 

[dwilfong]

These days very high strength ceramics are available. It would still need rethinking of the head design since things like threads and clamping systems can cause very high local stresses that start cracks in brittle materials. Still, I think in small engines the whole head button could be made from something like zirconium dioxide. The success of silicon nitride bearings is an indication of the possibilities. The very low heat conductivity would reduce losses and probably make water cooling unnecessary. A matching piston and liner might be needed. Conventional wrist pins would need to be large to reduce stresses. A ball system might work better. Since machining is often with diamond grinding. parts need to be close to finished size. Still, dental crowns are ground from solid ceramic blocks.

Lohring Miller

Lohring

Do you have any kind of info on what would work as a good coating.

You could put a dummy plug in the hole and coat only the chamber leaving the mating surfaces to the sleeve uncoated.

Would like to give this a try and see how it goes.

I have some Powerkote CBCI that I want to try. But would like some more options.

David

 

[lohring]

Take a look at

for an idea of what dental labs can do. The problem with things like threads is that the zirconia is machined in the sinitered state and needs to be fired after machining. That results in shrinkage that is compensated for in the machining, but I doubt that they are setup to thread mill. Tapping would result in an undersized hole. Zirconia is very strong and I bet accuracies of +-.0005" are routine in the finished product. A 100 mm (4") block like the one pictured costs over $200, though.
For coatings you could try http://www.swaintech.com/

Lohring Miller

 

[Charles Perdue]

The problem with ceramic heads, and some of the other poor heat conduction materials, they would allow run-a-way heat build up in the combustion chamber. The idea is to raise the combustion temperture some to allow for the more effecient burning of the fuel/air mixture while still being able to control the upper temp limit. Too much combustion chamber temp would make the engine go into damaging preignition and detonation. This would raise the temps even more and reduce the RPM's just before the engine lets go. If all you wanted was more head temp, do away with the water cooling and fins. Charles

 

[Jim Allen]

The heads, including; blank inserts; toroidal inserts; hemispherical inserts & taper inserts, that are used on very high performance racing two strokes are all made of aluminum. The preferred alloy that is used is 2017-T4 aluminum. All of the inserts are CNC machined. Most sit on top of the cylinder with some type of sealing gasket removed a distance from the cylinder's bore. 2017-T4 contains 3.5 to 4.5 % copper; .7% iron; 91 to 95% aluminum, plus other trace alloys. Its thermal conductivity would not be considered high when compared to other 2000 series or 6000 series aluminums that might be used for heads.

Jim Allen

 

[Tom Foley]

Wow ..can't believe anyone could have any room left in their head left for any of this after a WFO day at my shop !! Keep up the good work guys ..gotta get up early !!

 

[dwilfong]

Wow ..can't believe anyone could have any room left in their head left for any of this after a WFO day at my shop !! Keep up the good work guys ..gotta get up early !!

Thats what happens when you get old.

 

[Jim Allen]

Wow ..can't believe anyone could have any room left in their head left for any of this after a WFO day at my shop !! Keep up the good work guys ..gotta get up early !!

I get up at 6:00 am almost every morning. That's how much work I have, & yes David, many things will happen when you get old. :unsure: :unsure: :lol: :lol:

 

[Charles Perdue]

I am at work at 7:00am. Still have to work for a living and am **** proud that I am still able to do it.

They say that memory is the second thing that goes. I cannot remember what the first one was, but it must have not been that important cause I don't miss it. All I can say is that it should have happened a long time ago, then I may have amounted to something.......

Charles

 

[dwilfong]

This thread is about head button material. Not about how early a bunch of old men get out of bed and how hard thy think thy work. :lol: :lol: :lol: :lol: :lol: :lol: :lol:

My alarm goes off at 5:00am and I am in the truck by 6:00am. then it's up the 30' ladder most days messing with doors or under a leveler with the crane holding it up. If I get home by 6;00PM it's a great day.

But then again I'm only 50 with 3 stints in my heart. Then it off to the garage to mess with my toy boats.

Can't believe I wast this much time typing on this thing. should be cutting new buttons or some thing.

David

 

[Tom Foley]

Wow ..can't believe anyone could have any room left in their head left for any of this after a WFO day at my shop !! Keep up the good work guys ..gotta get up early !!

I get up at 6:00 am almost every morning. That's how much work I have, & yes David, many things will happen when you get old. :unsure: :unsure: :lol: :lol:

Sleeping in lately ?? :lol: :lol:

 

[Tom Foley]

This thread is about head button material. Not about how early a bunch of old men get out of bed and how hard thy think thy work. :lol: :lol: :lol: :lol: :lol: :lol: :lol:

My alarm goes off at 5:00am and I am in the truck by 6:00am. then it's up the 30' ladder most days messing with doors or under a leveler with the crane holding it up. If I get home by 6;00PM it's a great day.

But then again I'm only 50 with 3 stints in my heart. Then it off to the garage to mess with my toy boats.

Can't believe I wast this much time typing on this thing. should be cutting new buttons or some thing.

David

Quit smoking dummy !!

 

[Charles Perdue]

Hell, that ain't nothing. I get up and make coffee and homemade biscuits for the roosters when they decide to get up.

Charles

 

[moparbarn]

Wow ..can't believe anyone could have any room left in their head left for any of this after a WFO day at my shop !! Keep up the good work guys ..gotta get up early !!

I get up at 6:00 am almost every morning. That's how much work I have, & yes David, many things will happen when you get old. :unsure: :unsure: :lol: :lol:

GETTIN' OLD AIN'T FOR SISSIES. up at 6 am every day, work 8-10 hrs at age 60. take care of yourself david, it don't get easier..........