ESE's works engine tuner

**Lightbulb** · 2nd October 2018, 20:01

2024 is the best material for heads for model engines. While 6061 and other alloys do work, the heads that use taper seating glow plugs, or heads that have contra pistons in them, ie diesels, all other alloys fail very early on. While the 2024 lasts the longest. Even 2014 doe not last as well as 2024.
Like wobbly said, 2024 is hard to beat.
Neil

**wobbly** · 2nd October 2018, 20:25

Ha, Ha , here we have the classic catch 22 ,why do we think chamber thermal conductivity is an asset ?
We have the wank yanks going on about " cool Head " technology as tho its the last word in performance enhancement.
But no , reality is a little more subtle.
We want to keep as much heat of combustion contained within the expanding gas above the piston.
Having a great heat path into the water via the insert dome surface is counter productive to this basic concept.
To the point that ceramic coating just the chamber - makes more power.
BUT , we want to pull heat out of the squish band boundary layer, to prevent spontaneous combustion of the trapped end gases ie detonation caused by free radical formation.
Thus I now believe that clever concepts to separate the chamber cooling rate , from the squish heat transfer path is a key process to be considering.
I have the answer to this conundrum , but NDA restraints limit what i can say at this time.
Suffice to say - insert materiel properties is the last issue of real concern.

**shnaggs** · 3rd October 2018, 01:44

Originally Posted by wobbly

Ha, Ha , here we have the classic catch 22 ,why do we think chamber thermal conductivity is an asset ?
We have the wank yanks going on about " cool Head " technology as tho its the last word in performance enhancement.
But no , reality is a little more subtle.
We want to keep as much heat of combustion contained within the expanding gas above the piston.
Having a great heat path into the water via the insert dome surface is counter productive to this basic concept.
To the point that ceramic coating just the chamber - makes more power.
BUT , we want to pull heat out of the squish band boundary layer, to prevent spontaneous combustion of the trapped end gases ie detonation caused by free radical formation.
Thus I now believe that clever concepts to separate the chamber cooling rate , from the squish heat transfer path is a key process to be considering.
I have the answer to this conundrum , but NDA restraints limit what i can say at this time.
Suffice to say - insert materiel properties is the last issue of real concern.

Originally Posted by Lightbulb

2024 is the best material for heads for model engines. While 6061 and other alloys do work, the heads that use taper seating glow plugs, or heads that have contra pistons in them, ie diesels, all other alloys fail very early on. While the 2024 lasts the longest. Even 2014 doe not last as well as 2024.
Like wobbly said, 2024 is hard to beat.
Neil

Originally Posted by Michael Moore

Matweb seems to disagree on 2024 vs 6061 (they didn't have the same temp range listed for CTE as for 6061)

2024-T6 CTE linear 23.8 µm/m-°C @Temperature 20.0 - 200 °C
2024 thermal conductivity 151 W/m-K

6061-T6 23.6 µm/m-°C @Temperature 20.0 - 100 °C
6061 thermal conductivity 167 W/m-K

Even if CTE is a wash 6061 seems to be better at conducting heat.

In Volume 2 of his series John Bradley mentions that the 2xxx and 7xxx series may have more corrosion issues and should be clear anodized to protect them. He also says that 2024 is much better than 7075 for fatigue resistance, and 7075 T6 can have a problem with fast fracture failure.

6061-T6 is similar in properties to 356-T6 casting alloy that might be used to make a cast head, perhaps it is good enough? It is certainly readily available, at least in the USA.

cheers,
Michael

Originally Posted by wobbly

I have seen several 7075 inserts crack , it seems to work harden under cyclic thermal of stress loads.

Originally Posted by Muhr

https://www.makeitfrom.com/compare/2...97075-Aluminum

Originally Posted by wobbly

2024 alloy is technically the go ( good temp strength ) but as long as the insert is carefully designed ( thick enough ) and has the dome retained by the cover
then 6061 works perfectly.

Originally Posted by katinas

Would be better Al-Cu alloys - 2618, 2024, 2014. 2618- less thermal expansion and better thermal conductivity.

Great thank you guys for the input! I have some 6061 sitting in the shop so maybe I could have some trial and error on that, and then look into some 2024 down the road.

**jonny quest** · 3rd October 2018, 05:26

Can anyone provide a link to a video I'm looking for?

I believe it's an Italian racer that builds his own 125 GP bike from scratch. It shows him casting his own engines, all his transmission parts.... I can't seem to find it and don't remember the name

**Haufen** · 3rd October 2018, 05:31

Do a search on youtube for GNANI, sounds like him.

**Frits Overmars** · 3rd October 2018, 05:57

Here you go Jonny:

Gabriele Gnani making a cylinder.

part 1:
http://www.youtube.com/watch?v=I-2rJtnkYq4

part 2:
http://www.youtube.com/watch?v=Lj4h9...eature=related

part 3:
http://www.youtube.com/watch?v=A50p3...eature=related

**jonny quest** · 3rd October 2018, 06:08

That's it!

**TZ350** · 3rd October 2018, 06:17

Originally Posted by jasonu

The closure of Mt Welli has been on the cards since the mid 90's when we showed up to a parking lot full of containers.
Good on you for trying but good luck trying to convince the council to change their mind.

https://www.nzherald.co.nz/nz/news/a...ectid=12135782

Sadly, probably true, anyway it made the paper. Thanks for posting the link.

**dutchpower** · 3rd October 2018, 06:20

https://www.youtube.com/watch?v=YbjyTDe9cw8

https://www.youtube.com/watch?v=9PTKV1N3aOQ

https://www.youtube.com/watch?v=iQ1Dq48KHu0&t=17s

**peewee** · 3rd October 2018, 07:15

this is cool head insert. dont even think of stealing their design

**F5 Dave** · 3rd October 2018, 12:10

Crack that Whip!

**speedpro** · 3rd October 2018, 12:50

There won't be many that get that joke.

**jbiplane** · 3rd October 2018, 14:16

Originally Posted by Michael Moore

Matweb seems to disagree on 2024 v
Even if CTE is a wash 6061 seems to be better at conducting heat.
l

VAL14 and Val18 russian casting alloys which work fine and remain strong at 350°С Al–Cu–Mn

One can easily recreate Val 14 or buy for superior engine castings
Mn 0,5...0,9%
Si and Fe less than 0.1%
Cu 4,5...5%
Aluminum remain
Better protect surfaces contacting flame or water by anodizing

Deformating alloys 1215 have σ≥460Mpa at normal and at 150° σ=300
В-1213 σ≥490 МПа, at 150° =340Mpa

2024 and 6061 much weaker

Exist very special allous with add silver and stroncium and alloys made from powders