What Aluminum is used to make cylinder heads?
What Aluminum is used to make cylinder heads?
(OP)
I don't know if I'm approaching this the right way, but doesn't an aluminum head or any head in general get exposed to temperatures of 1000F+ during the combustion process? I know that they last a fraction of a second but after a while the head's combustion area will reach a temperature steady state. I'm guessing it should be about 500F or 600F (these are guess), since the fresh intake charge cools it off and also because of the water jackets absorbing that heat.
What kind of aluminum can sustain temperatures of that extreme?
I found out that some aluminum heads are made from A356 T6, but this type of aluminum is not made to handle temperatures above 300F.
Am I looking at this the wrong way?
What kind of aluminum can sustain temperatures of that extreme?
I found out that some aluminum heads are made from A356 T6, but this type of aluminum is not made to handle temperatures above 300F.
Am I looking at this the wrong way?





RE: What Aluminum is used to make cylinder heads?
Let me refresh your recollection of heat transfer calcs with the fact that ΔT across a resistance (film theory) is proportional to 1/htc of that resistance. Therefore, the combustion chamber is hot as hell in the center and not so hot at the walls, i.e. large ΔT. The cooling water/EG is the coolest thing in the system and since it's htc is large and ΔT is small so is the walls.
Good luck,
Latexman
RE: What Aluminum is used to make cylinder heads?
The heads that I know of are made from 356-T6.
RE: What Aluminum is used to make cylinder heads?
RE: What Aluminum is used to make cylinder heads?
There are some engines with unjacketed exhaust runners - the Pontiac V8 comes to mind - that also have no apparent heat issues when the heads are made of aluminum. The same company also used to make aluminum exhaust manifolds, which did have some erosion problems.
RE: What Aluminum is used to make cylinder heads?
RE: What Aluminum is used to make cylinder heads?
Can someone confirm to me, that during the induction stroke, does the entire chamber and top of piston gets cooled rapidly, therefore the average temperature is the exhaust temperature and intake charge temperature divided by two.
RE: What Aluminum is used to make cylinder heads?
RE: What Aluminum is used to make cylinder heads?
DELTA T
RE: What Aluminum is used to make cylinder heads?
RE: What Aluminum is used to make cylinder heads?
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RE: What Aluminum is used to make cylinder heads?
Its the same reason a copper lance can be shoved into molten Iron. A high conductivity metal with sufficient cooling jackets can handle very high temperatures.
RE: What Aluminum is used to make cylinder heads?
During a recent development program of a rotary engine we performed a temperature map all over the engine (including exhaust temps), and never saw anything close to 2000 degrees. 1300-1400 was the maximum measured temperature that we saw.
-Reidh
RE: What Aluminum is used to make cylinder heads?
RE: What Aluminum is used to make cylinder heads?
No one has mentioned this so I will chime in...There is a boundary layer as flame front grows that helps protect the surface temperature. This is not true in the exhaust port but there is a cooling intake reversion wave that helps the port and especially the valve seat...Preigniton (a much discussed subject) will blow away the boundary layer and you will burn a piston..
For my part there are more disadvantages to using aluminum heads then the weight advantage..I favor meehanite castings IMO.
Cheers
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