Aluminum Head Fuelie

[Michael J.]

Any truth in any of this?

http://blog.hemmings.com/index.php/2011/12/14/pre-production-fuelie-corvette-to-highlight-mecums-kissimmee-auction/?refer=news

[Stuart F.]

Re: Aluminum Head Fuelie

The entire story is about as I recall it from news articles and magazines of the time. However, the big question is whether any got into production and sold. That I never heard before.

Stu Fox

[Ridge K.]

Re: Aluminum Head Fuelie

I would be curious to hear how using aluminum in the cylinder head casting would allow for, higher compression, .......and "25 more horsepower".

Certainly the weight savings is an obvious plus. What am I missing on the compression aspect?

[Philip A.]

Re: Aluminum Head Fuelie

You would think they would have a photo of the head(s) since this is what sets the car apart. Aslo, I have been lead to believe that aluminum heads run cooler than cast iron allowing for additional compression (without detontation); all other things being equal.

[Duke W.]

Re: Aluminum Head Fuelie

Aluminum has one-third the thermal resistance of cast iron, so combustion chamber surface temperatures are less, which allows higher compression without detonation.

As a rule of thumb, all other things equal, an aluminum head will tolerate up to half a point more compression on the same octane.

I never understood why Chevrolet had problems with those early aluminum heads. The Allison division had plenty of experience with complex aluminum head castings for the V-1710 aircraft engine dating back to the thirties, but those heads had valve guide and valve seat inserts.

GM finally was able to produce a high-silicon aluminum block, which allowed pistons to run in linerless bores (the Vega engine), but I don't know of any manufacturers that successfully produced an aluminum head that would last without valve guide inserts and certainly without valve seat inserts, especially on the exhaust side.

The aluminum head Cosworth Vega engine with its compact pentroof combustion chamber was rated half a point higher (8.5:1) than the open chamber iron head Vega engine, and the CV will tolerate a very aggressive spark advance map on regular unleaded or two points higher true compression with an aggressive spark advance map on modern premium unleaded.

Nevertheless, Chevrolet went ahead and raised the CR to 11:1 with the 461 cast iron clone of the ill-fated aluminum head, but when the bore size increased to four inches in 1962 Chevrolet was forced to double gasket those engines beginning in mid production due to customer detonation complaints, and those 340/360 HP 327s had a pretty lazy spark advance map to begin with.

Also, the 283/275HP FI engine would have been more prone to detonation due to its shorter cam that increased the DCR relative to the Duntov-cammed 315HP engine.

Most of the increased power from the 461-head 283s is probably due to the larger and better flowing inlet ports.

IIRC, a few years ago someone on the board posted pictures of those early aluminum heads that are in his possession, but I don't recall it they were serviceable or had ever been on a running engine.

Duke

[Nicholas L.]

Re: Aluminum Head Fuelie

Here is a link to pictures and documentation when that car was owned by a dealer in Georgia. It received a Duntov at the 2007 Nationals in Marborough, MA. My 1960 was parked next to it during judging.

http://www.vintagecorvettes.com/1960big.html

[Cecil L.]

Re: Aluminum Head Fuelie

Apparently there were a few aluminum blocks also as this one cast in 59.

http://www.youtube.com/watch?v=qPgI3FV-jqo

[Clem Z.]

Re: Aluminum Head Fuelie

if they are the original heads i bet they sleeved the valve guides

[Ridge K.]

Re: Aluminum Head Fuelie

Aluminum has one-third the thermal resistance of cast iron, so combustion chamber surface temperatures are less, which allows higher compression without detonation.

As a rule of thumb, all other things equal, an aluminum head will tolerate up to half a point more compression on the same octane.






.

Duke

Thanks for that explanation, Duke!

[Peter M.]

Re: Aluminum Head Fuelie

The car looks like the REAL DEAL to me.

[Jim L.]

Re: Aluminum Head Fuelie

Here is a link to pictures and documentation when that car was owned by a dealer in Georgia. It received a Duntov at the 2007 Nationals in Marborough, MA. My 1960 was parked next to it during judging.

http://www.vintagecorvettes.com/1960big.html

Hold the phone..... The engine pad for #7941 described in your link has the 290 HP "CS" suffix and the inventory of the disassembled engine mentions a 692 head.

This doesn't sound at all like a 315 HP CZ engine to me.

Jim

[Loren L.]

Re: Aluminum Head Fuelie

There is an old Restorer article by Dave Campbell (then at GH) that located the records that showed 11 (Memory?) CZ motors had been built, but all went to Engineering testing and none went to St Louis.
If they were to have showed up in a car, you can bet that the Cunningham Le Mans cars would have had them (for all the $$$ GM was spending) but they did NOT. But Le Mans #1 did get a CZ SHORT BLOCK as its replacement motor and that was in the car when it passed through the Le Mans Tech inspection but WITHOUT the aluminum heads.
I can also recall a red 60 going through an RM auction 5-6 years ago
claiming the aluminum heads (had white coves, though). I can remember talking to someone who claimed to be a friend of the owner. When I asked where the guy had found it, the supposed friend said "He took it in on trade on a phoney L88 he was selling.".

[Dick W.]

Re: Aluminum Head Fuelie

Hold the phone..... The engine pad for #7941 described in your link has the 290 HP "CS" suffix and the inventory of the disassembled engine mentions a 692 head.

This doesn't sound at all like a 315 HP CZ engine to me.

Jim

Good catch

[Roy S.]

Re: Aluminum Head Fuelie

This car went through the system with cast iron heads received the Duntov award with cast iron heads, if it now has aluminum heads that is not the way the owner that showed it and earned the awards feels it was originally equipped. He did hear the stories saw the Noland Adams claims and he also purchased a set of aluminum heads for it, but they were never installed by him or claimed as original by him.

[Jim D.]

Re: Aluminum Head Fuelie

This car went through the system with cast iron heads received the Duntov award with cast iron heads, if it now has aluminum heads that is not the way the owner that showed it and earned the awards feels it was originally equipped. He did hear the stories saw the Noland Adams claims and he also purchased a set of aluminum heads for it, but they were never installed by him or claimed as original by him.

And now we have the truth. Thanks for posting.