[Takis]

Please correct me if I am wrong ,
1.all 105/115/116 stock cylinder heads had an 80 degrees included valve angle
2.same goes for the GTA 1600 and GTA 1300 Junior with carbs
3.GTAm had 45 degrees angle as did the GTA 1300 Junior with fuel injection
4.75 2lt twin spark used 46 degrees valve angle
5.115 series TIPO numbers were also used for the GT 1300/1600 Junior Euro spec models
6.there were Autodelta 1300 cylinder heads with 4 valves per cylinder fuel injection and single plug with 45 degrees included valve angle
waiting for your comments.
Happy and prosperous New Year to everyone.
Takis.

 

[BigSwede]

I thought the old head was 86 degrees and the new (TS 8v) was 46 degrees.

Direct comparison between 75 TS pistons (10:1) and 75 2.0 carb pistons (9.5:1)

 

[papajam]

5.115 series TIPO numbers were also used for the GT 1300/1600 Junior Euro spec models

I have the 1300 GT Jrs as 105 series only; 105.30 (LHD) and 105.31 (RHD).
The 1600 Jrs are 115.03 LHD and 115.05 RHD (are these Series 1?) and 115.34 from 1974-76 (Series 2?).

 

[BigSwede]

a friend over here has a 115 Spider. Adding to the confusion?

 

[papajam]

Yes, since the question pertained to the Bertone GTs.

I show a total of 21 different model 115 series cars having been produced. Will post the list if interested.

 

[BigSwede]

lol, but I was thinking about the 115 being a US-only thing.

 

[Takis]

Papajam you are right , the GT 1300 Junior remained TIPO 105.30 till the end , with series 4 given TIPO 105.30S.
Starting from 1970 :
TIPO 115.09 Giulia 1300 Super LHD
TIPO 115.10 Giulia 1300 Super RHD
TIPO 115.03 GT 1600 Junior 1972 series 3
TIPO 115.07 Spider 1600 Junior
TIPO 115.24 1600 Junior Zagato
TIPO 115.00 2000 Berlina iniezione America
TIPO 115.01 2000 GT Veloce iniezione America
TIPO 115.02 2000 Spider Veloce iniezione America
TIPO 115.09S Nuova Super 1,3
TIPO 115.34 GT 1600 Junior series 4
TIPO 115.35 Spider 1600 Junior
TIPO 115.36 2000 Berlina
TIPO 115.38 2000 Spider Veloce
TIPO 115.41 2000 Spider Veloce iniezione America 1977
Takis.

 

[papajam]

...and here's the rest of the 115 list;

115 A1 Spider 2.0 '89-'90
115 A1A Spider 2.0 Kat '91-'93
115.00 2000 Berlina - USA
115.08 Giulia Spider 1600 - RHD?
115.29 Giulia Super 1.6
115.30 Giulia Super 1.6 - RHD?
115.62 Spider 1.6 '86-89
115.66 Spider 2.0 '86-'89

Im curious about this 115.36 Berlina; I've not yet seen a reference to this model. What exactly is it?

So from TAKIS's list, a 115.03 Junior with a 1600 is considered a Series 3 Junior the same as a 105.30 Junior with a 1300?

 

[OldAlfaGuy]

Cylinder Head Specs

GTA and GTA Jr twin plug heads are rare and expensive. Besides the scarcity of the heads, the dual ignition for them is getting even harder to find. Those parts are REALLY expensive. I know of one twin plug engine where the owner converted to a distributor from an american V8. I have no details, but obviously it can be done. (BTW, the GTA and GTA Jr heads did have the same 90 degree included valve angle as their single plug counterparts.)

The 60 degree GTAm head (also used by Autodelta on the final versions of the GTA Jr that competed in the European Touring Car Championship into the '70's) is even rarer than the GTA/GTA Jr head (the ignition setup was the same as used in the GTA and GTA Jr). I don't think many were produced to begin with. Plus, the only place you could race with it in the US at the time was IMSA GTU, and a 4 cylinder Alfa was not competitive against 6 cylinder Porsches and Datsun Z's. And it was not legal in SCCA production/sedan racing. So just a handful of the narrow angle heads ever showed up here. Since then, other GTAm heads and engines have no doubt been brought over from europe. But the rarity of the older twin plug heads (both 90 and 60 degree) and their ignition systems pretty much keeps them in the vintage/ collector car market.

 

[Takis]

Forgot one :
TIPO 115.40 Giulia Nuova Diesel.
Papajam from 1975 the Berlina 2000 previously TIPO 105.12 was given TIPO 115.36 introducing some new details for the interior and the mechanicals like different headrests and electronic ignition.
The GT 1300 Junior series 3 and GT 1600 Junior series 3 is the same car differing only in the engine's capacity , the same goes for the GT 1300/1600 Junior series 4.
Dear OldAlfaGuy,
The stock cylinder heads from 1300 to 2000 are 80 degrees not 90 , included valve angle , the GTA 1600 and the GTA 1300 Junior with carbs are also 80 degrees , the GT Am and GTA 1300 Junior with injection are 45 degrees not 60.
Takis.

 

[PSk]

Forgot one :
TIPO 115.40 Giulia Nuova Diesel.
Papajam from 1975 the Berlina 2000 previously TIPO 105.12 was given TIPO 115.36 introducing some new details for the interior and the mechanicals like different headrests and electronic ignition.
The GT 1300 Junior series 3 and GT 1600 Junior series 3 is the same car differing only in the engine's capacity , the same goes for the GT 1300/1600 Junior series 4.
Dear OldAlfaGuy,
The stock cylinder heads from 1300 to 2000 are 80 degrees not 90 , included valve angle , the GTA 1600 and the GTA 1300 Junior with carbs are also 80 degrees , the GT Am and GTA 1300 Junior with injection are 45 degrees not 60.
Takis.

Takis,

I respectively think you are wrong regarding the 45 degree valve angle of the GTAm head ... have a look at this post by Papajam: Autodelta GTA 1300 Junior

Catalogue indicates 60 degrees. Maybe the later twin spark head (75 and 155) are 45 degree ???

Pete

 

[Jim K.]

All 105's were only 80* production heads (and 90* for the 102 series) and then there were the 46* GTAm heads. They are even wrongly listed as 60* in the Competition Supplement catalog (~1970).
Jim K.

 

[Takis]

Please allow me to add to Jim's answer :
from the "Alleggerita" book on the chapter of the GTA 1300 Junior: ...from January 1st 1971 onwards the GTA Junior with Spica or Lucas injection is allowed to race in Group 2 and therefor a new cylinder head is developed with valves placed in at 45* angle...
from the same book on the chapter of the GTAm: ...valves were enlarged from 41.15mm to 45mm for the inlet and from 37.2 to 41mm for the exhaust valve respectively.They for an angle of 45*.
Jim I also think that the 75 2lt TS head has the valves at 46* , I saw it written inside your book , please correct for this.
Takis.

 

[Jim K.]

Yes, the TS has a 46* valve angle (from many AR sources). This is also valid for the 155, 1,7/1,8/2,0 engines.
I don't think there ever was an AR 60* head, production or competition.
The 60* error was propagated many times in the NON-factory literature.
Jim K.

 

[OldAlfaGuy]

GTAm Head specs

The included valve angle issue is driving me nuts.

OK, I will accept that all post-102 series PRODUCTION single plug four cylinder heads are 90 degrees.

But I can't let go of the GTAm valve angle. It's not that I think I'm right, or want to be right. I don't really care what the angle is. My problem is that ALL official Alfa Romeo printed material distributed in the United States back then referred to it as "60 degree." It wasn't a one-time error in a non-official publication. In fact, the technical people who were employed at Alfa Romeo and supported racing efforts at the time always called it either "the 60 degree head" or simply the "Am" head for short. It was always referred to as 60 degrees, never 45 degrees.

I have scanned a page from a bulletin that Alfa sent to its dealers notifying them that the GTAm head had been homologated for use on the Alfetta models (116 series). In the bulletin, they included a photocopy of the document that Alfa Romeo filed with the FIA. Hopefully, my scanned page gets attached to this message. On it, you can see the FIA document/page number (FIA 5497/1/1V). And on it, the head is described as "Twinplug with 60 degree valve angle."

BTW, anyone got an "Am" head laying around? It should be easy to measure included valve angle. It's not that I question anyone's expertise (only my own!). I just can't believe that everyone at Alfa Romeo in the U.S. got it wrong so completely for so long.

OldAlfaGuy

P.S. - The file of the scanned page is too large (over 439.7 KB and it says the limit is 150 KB). Sorry. Anyone got any ideas on how to get it sent to the Alfa Romeo BB?

 

[vintageveloce]

Uhm, I don't know anything about this.... but I note that geometrically, if the included valve angle was 60 degrees, the angle would be 45 degrees to the head/cylinder surface. Could the 60 and 45 degree terms mean the same thing? Do the documents ever say "45 degree included valve angle" or just 45 degree head? These could be construed to mean the same thing...
Just a silly thought.
C

 

[PSk]

Uhm, I don't know anything about this.... but I note that geometrically, if the included valve angle was 60 degrees, the angle would be 45 degrees to the head/cylinder surface. Could the 60 and 45 degree terms mean the same thing? Do the documents ever say "45 degree included valve angle" or just 45 degree head? These could be construed to mean the same thing...
Just a silly thought.
C

Hmmm, not sure I follow you here; I guess one valve could be 45 degrees to the head/cylinder surface but that would mean the other was only 15 degrees off the vertical. I think (while not dead even) that Alfa Romeo heads are close to symmetrical, ie:

Pete

 

[vintageveloce]

PSk, Hmm... I swear I wasn't drunk when I wrote that, but the numbers don't add up. Sorry about that!
C

 

[jpv]

I don't want to confuse more this subject but I'm going to leave here the info that I have:

The original 1900 engine had a 90º head;

The first bertone coupe, the Giulia Sprint GT, had a 1600cc engine with the 90º valve angle head;

When Alfa released the GTA, it had designed the twinplug head with an 80º valve angle and aplied this valve angle to the rest of single plug heads. Hence the model Giulia Sprint GT Veloce, this car had a 1600cc engine with 80º valve angle single plug head.

I don't know very well the other GTAm and Junior heads, but all the other single plug engines since the GTA have an 80º valve angle.

The reason for a narrower angle is to improve the combustion chamber, the flat piston and a hemispherical chamber is the best solution as proved by cosworth in the DFV and Twin Cam Lotus.

The pent roof 4 valve design is a compomised solution due to costs of making a hemispherical 4 valve design.

There are engines with a 4 valve hemispherical design, I've seen mono cylinder motorbike engines with this solution, and F1 cars use this solution.

Hope this helps.

JPV

1969 GT 1300 Junior (GTA replica with 2 liter engine)
1972 2000 GTV
1976 Porsche 924
1991 Mazda Miata MX5

 

[alfatwincam]

On valve angles dont always presume that the inlet angle is the same as the outlet .It was different on AUTODELTAS special narrow valve angle heads.Example on the 1300 junior GTA in 1969 it was 22.4* inlet & 24.7* outlet bringing a total of 47.1*. On later 1300 junior narrow valve angle heads it was made even closer to 20.10* inlet & 20.20* outlet bringing a total of 40.30*.The illustration above by PSK is the correct way to determine valve angles on a cylinder head.