Steel for cylinder head

[MRSERIOUSMOJO]

Probably a stupid question but could steel be used for a 2 stroke cylinder head?.. I have a few ideas I'm working on and if I could use steel it would be much easier than trying to cast aluminum...I'm talking like maybe 1/4 to 1/2 machined plate. Any ideas on this?..Thanks

 

[The_Aleman]

Not a very good idea IMHO. A steel head will just become a hot spot and lead to detonation and possible engine damage.

Even if it were water-cooled it would probably still run way too hot. Aircooled engines are aluminum or magnesium for a good reason!

 

[Frogslayer]

The reason being is because it's super cheap. Have you thought about machining aluminum instead of casting it?

 

[The_Aleman]

The reason being is because it's super cheap. Have you thought about machining aluminum instead of casting it?

Um no, I was thinking it's because aluminum has between 6-12x better thermal conductivity than steel, depending on grade.

Metals, Metallic Elements and Alloys - Thermal Conductivities

Thermal conductivities of common metals, metallic elements aand alloys.

www.engineeringtoolbox.com

 

[JerboaJohn]

I saw couple listings on ebay saying stainless steel head, but think there's no way could they be,, more expensive to cast than aluminum actually! bcs the heat needed to melt steel is like 2x what the temp for aluminum is (2750 vs. 1220)

re: "machine a head rather than cast?" I did that. helluva lot of work! between the lathe, milling, drilling and tapping... cost me only $28 bucks tho but sooo many hours

 

[The_Aleman]

Stainless head? Ugh, that would be even harder to cool than a carbon steel head! Air-cooled engines are made out of materials that dissipate heat easily. Steel, whether carbon or stainless, is not an ideal material to make an aircooled head from.

 

[China Girl Steve]

Yes, steel will work but it does transfer heat slower so it needs to be thinner and have more fin surface area. Typically steel or iron heads need the compression lowered about 1/2 a compression ratio for detonation resistance. Even taking advantage of steel's greater strength by machining it thinner, it is hard to match the light weight of aluminum.

If you have access to a lathe, buy a 1" long length of 4" to 6" diameter aluminum round bar which should be in the range of $10.
Understand that some metal supply places charge cutting fees and often a minimum purchase fee.
Often they have deals on left-over ends or damaged pieces.

In theory less heat transfer is a good thing for thermal efficiency, especially in an engine that requires low compression for other reasons. I think a steel cylinder head sounds like a good experiment.

 

[JerboaJohn]

yes steel can work as a head. they still make cast iron heads for many small engines , low compression. but to do it, you're already putting much effort into a part that will not enhance any practical characteristic of a CG. make it heavier? lower it's compression?? maybe if you're after 12,000+ rpm, run it only for nitrous drag racing, and after a rusty steampunk look (lol) maybe it could be a viable thing.
I have more than 25 hours machine time in the head I made for my 55cc CG so far. never did anything like that before but it was for necessity and think I paid $18 for a 4" round x 2" 6061 billet
Oh I have a brass billet too somewhere but that head project got pushed back a year or 2,,