NR 5port head button

[Blackout]

Aluminum vs. Brass. Maybe the difference in thermal conductivity???...

 

[RodneyPierce]

Craig, Aluminum has a better thermal conductivity then brass, so that doesnt really make much sense. I was thinking the was the reason as well at first, but after some quick research, appears that the thermal conductivity of aluminum is almost double that of brass. It does appear that brass tends to start to conduct the heat at a lower temperature then aluminum does though... Since thermal conductivity of materials is temperature dependent, it appears that at 68* brass conducts 64k, where as aluminum at 200* conducts 124k. So I dont know if that is the temperature that the material starts to conduct heat, or why the temperature tested is different there. We need someone to explain thermal conductivity in lehman's terms. LOL

 

[Ted buckley]

the so called "hybrid" is pretty much the good old nova that they sold for many years.they did make the sleeve o.d. larger,and have eliminated the stupid o rings in the water jacket( still too much water volume),but it's my favorite 21 engine to date,and modded runs like stink

"but it's my favorite 21 engine to date,and modded runs like stink" Trying to figure out if "Stink" is a good thing? :blink: Does this mean the Hybrid is better "Not Modded" or does Stink Run Fast? I just bought a Hybrid P/L that I want to send you - but now Don't know? ipb.global.registerReputation( 'rep_post_438821', { domLikeStripId: 'like_post_438821', app: 'forums', type: 'pid', typeid: '438821' }, parseInt('') );

LOL Yes Ted, that would be a good thing for sure. For best results, have Steve do the complete motor, not just the liner. Maybe 90% is in the props, though. Richard D

i won't do just a liner

Steve, I'll be sending the whole motor with New parts: P/L, Bearings & new head button(Aluminum) unless you want to throw a brass on there - you'll have to let me know the addition cost? Yes Dicky, I know about the props.. And I think that the "Run's like Stink" must be a cultural thing depending on where your from or how old you are? I heard on KQRS this morning that they took to word "Vivacious" and it has 2 different meanings depending on your age/location. :lol: I should have gotten the Stink-thing though

 

[Blackout]

Craig, Aluminum has a better thermal conductivity then brass, so that doesnt really make much sense. I was thinking the was the reason as well at first, but after some quick research, appears that the thermal conductivity of aluminum is almost double that of brass. It does appear that brass tends to start to conduct the heat at a lower temperature then aluminum does though... Since thermal conductivity of materials is temperature dependent, it appears that at 68* brass conducts 64k, where as aluminum at 200* conducts 124k. So I dont know if that is the temperature that the material starts to conduct heat, or why the temperature tested is different there. We need someone to explain thermal conductivity in lehman's terms. LOL

Unless holding in more heat makes more power.

 

[RodneyPierce]

Too much heat and you get deto.......

 

[steve wood]

don't beat it to death.just try it.i would not be using it if it wasn't better.

btw mark voorhies says his 1.01 brass button stil shines like a baby's butt

 

[Paul Traufler]

Detonation will occur in a hot high compression motor and IF you have any roughness in the combustion chamber that will make a “hot spot” that will trigger detonation. I think the brass helps in that it is somewhat harder then aluminum and after some use and a few blown glow plugs putting some material on the aluminum head button to make it rougher. The brass head buttons do not have the same troubles so they stay smooth and since this helps keep detonation at bay should work better. I doubt it is a heat transfer thing as the heads are water cooled and should not make a huge difference in internal motor temps. Detonation happens VERY fast, almost like a explosion so that flash over point is very hard to understand. Just my 2 cents worth.

Paul

 

[RodneyPierce]

don't beat it to death.just try it.i would not be using it if it wasn't better.

btw mark voorhies says his 1.01 brass button stil shines like a baby's butt

I couldnt agree with this more, was just trying to help Charles pry into WHY it makes a better button (like he was looking for).

 

[dwilfong]

The main reason for brass it is dose not pit like alum. once the pitting starts it just compounds its self with the chamber being roughed up. Also you can polish the brass real nice with lapping compound. this makes for a perfect surface for the air and fuel to move over. The brass will also maintain a more constant temp with less temp change

Heat is a good thing in the chamber. Nitro need heat to burn good. you don't want heat in the rest of the eng.

Using a brass button in conjunction with a custom cooling head will keep the heat were it belongs in the chamber.

If you cool just the top of the button with water and separate it from the case and sleeve it is much easer to control eng temp.

This way you can run the eng rich to cool the case and piston and still have the heat in the head to burn all the extra fuel.

You will not see deto on the brass button. with brass you have to look at the top of the piston to get a read on what is going on.

Just my take on it.

David

 

[Charles Perdue]

I made a head from 303 stainless, hard and shiney. How did it work.....the entire glow plug turned blue and then red hot, not enough heat transfer.

 

[dwilfong]

I made a head from 303 stainless, hard and shiney. How did it work.....the entire glow plug turned blue and then red hot, not enough heat transfer.

very interesting.

 

[Ian Inverarity]

I made a head from 303 stainless, hard and shiney. How did it work.....the entire glow plug turned blue and then red hot, not enough heat transfer.

Charles

Was the head button water cooled?

 

[Terry Keeley]

Hey Steve: Care to share what sorta volume your running on the Nova?

About 0.17cc is as small as I can go in my little mono with the CMB.

 

[Charles Perdue]

Yes, I was going from one extreme to the other trying different materials. Test has not been completed.

Charles

 

[dwilfong]

Yes, I was going from one extreme to the other trying different materials. Test has not been completed.

Charles

what else are you going to test.

gold alloy would make a nice button. imagine that a toy boat with a golden head button. :wub:

Sorry could not help myself as usual.

I get like this from time to time. :blink:

 

[Charles Perdue]

Yes, gold or silver would be a good material to test in the opposite extreme.

Don't worry about the comment, I get carried away sometimes myself, especially after a few sips of muscadine juice. :unsure:

It is raining, wind blowing and cold here right now. This kind of weather is only good for two things, drinking wine and shucking corn, thank goodness, I do not have any corn to shuck.

It used to be a third thing but in my old age, I can't remember what it was.

 

[SayMikey]

Yes, gold or silver would be a good material to test in the opposite extreme.

Don't worry about the comment, I get carried away sometimes myself, especially after a few sips of muscadine juice. :unsure:

Musca,musca,musca mmmmmm where yoiu get that........Hey you going to stroll over to Huntsville in November?

 

[Charles Perdue]

I thought that just maybe the word muscadine would bring you out Mikey.

I should be about through with digging in my lake in several weeks and I thought about riding down to Huntsville. Are you going?

 

[SayMikey]

Yes after Thanksgiving hope to see ya there. Been over a year

 

[mark ham]

Has anybody tried titanium?