[1750racer]

Just wondering if anybody out there is racing or building an early style Autodelta 16v engine. This pre-70 style differs from the later Autodelta 16v in that it had unequal bore spacing monosleeve, exactly the same bore spacing as the GTAm engine. It was commonly used for motor boat racing. I recently obtained this rare head and a monosleeve block with a bore of 86mm and am trying to decide on which way to proceed. Should I go with the historically correct 86mm bore and build as a 1900cc, or prepare a 2 liter engine with a 84.5mm bore and standard 1750 stroke, or go for the smaller FIA legal 1300cc build??

I’m missing some of the small head items like lifters and some of the bearings so if you have a similar engine and have accessed some of the parts (cam bearing, lifters, new valves, etc) or just want to have a discussion about these engines, either add to this post or drop me a private message and I’ll reply by email.

 

[PSk]

What crank makes the 1900 engine, a 1600 one?

Anyway must be shorter stroke than the 1962cc one so that is what I would build. Awesome purchase.
Pete

 

[PAUGNUT1275]

1900 Monosleeve

Yes, a 1900 monosleeve engine had the 1600 stroke crank.

 

[PSk]

Thanks. You would need a short stroke to make the most of that 4 valve head and to keep piston speeds down.

I wonder what power and at what revs?
Pete

 

[kengta]

Serial Number

Hi, Just wondering what the block is, 1600 or 1750, and what the serial number markings are on the block, either on the pad on the intake side or on the bell house flange on the exhaust side.

Nice find BTW.

Regards

Ken

 

[Zagato_Olaf]

16v parts in the Performance Options Catalog

Hi, Just wondering what the block is, 1600 or 1750, and what the serial number markings are on the block, either on the pad on the intake side or on the bell house flange on the exhaust side.

Nice find BTW.

Regards

Ken

Dear Ken,

I suspect that you have checked the Performance Options Catalogs (POC) nr 1 to 4 to see what information was available for the pre 1970 16v heads? I couldn´t find anything in the first two catalogs. In POC nr. 3 from 1971 there is some info on the 4 cilinder Marine engine but it is scarce. And in nr. 4 there is some info on the 16v heads but they seem to indicate 116 instead of 105 heads.

Ciao! Olaf

 

[1750racer]

Hi, Just wondering what the block is, 1600 or 1750, and what the serial number markings are on the block, either on the pad on the intake side or on the bell house flange on the exhaust side.

Nice find BTW.

Regards

Ken

The only number on the block is 105001010 AD GR5
The deck height suggests it's based on a 1750 block.

 

[1750racer]

They are generally listed as having 240 to 250 hp at 8000rpm. But keep in mind that in those days it was common to quote SAE Gross horsepower whereas SAE Net horsepower is now used. 220 Net hp may not sound like a lot but I'm sure if a 16v engine was race prepared incorportating new technology cams, porting, valves, etc, the hp figure could be significantly improved.

 

[PSk]

They are generally listed as having 240 to 250 hp at 8000rpm. But keep in mind that in those days it was common to quote SAE Gross horsepower whereas SAE Net horsepower is now used. 220 Net hp may not sound like a lot but I'm sure if a 16v engine was race prepared incorportating new technology cams, porting, valves, etc, the hp figure could be significantly improved.

Would need a significantly shorter stroke (and larger bore) to make much more power. The bore stroke ratio is probably the hardest old fashioned part of these engines to resolve.

That is why the Sud engine can make considerably more power per cc than the Nord engine, even in 2 valve form.
Pete

 

[1750racer]

Which would lead one to consider rebuilding it as a 1600 or FIA legal 1300cc.
However i have heard of guys recently getting good hp out of them in 2 liter racing form although I can't confirm the bore/stroke ratio being used. I was hoping this forem would bring out one these knowledgeble racers.

 

[Zagato_Olaf]

Performance Options Catalog III from 1971

Dear 1750 Racer,

I checked the Performance Options Catalog III published in November of 1971. You can also check Performance Options Catalog IV published in February of 1977.

On page 2 of POC III, it mentions the crankcase with number 10500.01.010 AD/GR5 as the "1900" Prepared Crankcase, Monosleeve Type. It also mentions the "1900" Monosleeve with a bore of 86.0 mm as you quoted before.

Indeed the crankshaft 10532.02.010.99 "racing" with a 82.0 mm stroke is mentioned as the (1600)GTA/1900 crankshaft for such an engine. Pistons for this engine in the 16 valve configuration with a bore of 86.0 mm are mentioned as 10532.02.030.96.

It would be great in my opinion to see a "1900" 16 valve engine come back to live. Have fun deciding what to do!

Ciao, Olaf

 

[Alleggerita]

The relevant stroke/bores are:

1500 B: 83.4 S: 68.5
1600 B: 86 S: 68.5
1900 B: 86 S: 82

I am familiar with only one rumoured 1900 engine running with a regular twin plug head - it does seem to run very well. Otherwise no idea where the stories about making a lot of power out of types of engines come from - certainly there are not many around. They are quite different from the 1750/2000 GTAm.

While I certainly would think that an engine like yours could make power, to develop it with current materials and technology (eg cams, pistons etc)would likely not be a cheap endeavour ...

BTW, what are the measurements on you liners and crank?

1500 and 1600 are based on a bored out 1300 block and 1900 on a bored out 1600 block. Crank should be fully counterweighted.

Which would lead one to consider rebuilding it as a 1600 or FIA legal 1300cc.
However i have heard of guys recently getting good hp out of them in 2 liter racing form although I can't confirm the bore/stroke ratio being used. I was hoping this forem would bring out one these knowledgeble racers.

 

[1750racer]

Thanks for the info.
Unfortunately no crank came with the engine.
Liners are 154mm tall (and 86mm ID).

 

[cstlhn]

From the look of it the head looks very similar to a Ferrari 4 Valve. I will look around to see if I still have some old cam followers I could dimensions from. Not sure if the valve lash caps sat on valve stems or in the cam followers (like Fiat & VW). I have found that there is a lot of interchange between Italian manufacturers.
I like the intake manifold and would love to find a slide valve manifold for a two valve motor?

 

[UlrichGTA]

16 Valve engine

Hallo 1750 racer,
nice to hear of one of this masterpieces from italian race technology.

i own and work with this typ of engine long time. I bought the engine apart of the car 1980 and the car 2011, a race prepared GTA 1300 ,driver war T.Zeccoli , and Autodelta as first owner in the Libretto. Is was one of four engines in the german speaking countries in that period delivered from C.Chiti over Klaus Steinmetz , the racemanager of Alfa Germany in that period. The pre-owner bought the car direct from him 1975 in Settimo Milanese with the usual trouble in Italy .Means: the car was not ready at former declared date, the engine blow the headgasket at the testdrive in Monza. Luccky, that the car was not payed before delivery as wished from Autodelta!!!After reparing , blowing the next gasket one day later same place. Than, he take the car to germany and prepared the engine with his owne correctness. But the engine never reached the declared and prised horsepower of 180 HP!!! So , he race the car with the narrow head 2 valve engine without trouble and forgot the 4valve- engine.
In the last 30 years, i collected some spareparts for these typ, so in the moment , i prepare the car for my son Max, he race my other GTA 1300 with Carb-engine with succes and wish more power.

 

[Alleggerita]

That was a 1300 engine you are talking about? Same head though.

Helmut Haehn quite successfully ran a 4-valve 1300 in 613124 for quite a few years.

Regarding crankshafts: Reproductions for both 1300 and 1600 fully counterweighted cranks are available from OKP.
OKP Parts & Engineering for Italian Cars - Die Alfa Romeo Spezialisten: Racing Kurbelwellen GTA / Montreal

Also there are American made fully counterweighted 1600 reproductions. Possibly SRGRAY on this board may be able to assist with supplying those.

Hallo 1750 racer,
nice to hear of one of this masterpieces from italian race technology.

i own and work with this typ of engine long time. I bought the engine apart of the car 1980 and the car 2011, a race prepared GTA 1300 ,driver war T.Zeccoli , and Autodelta as first owner in the Libretto. Is was one of four engines in the german speaking countries in that period delivered from C.Chiti over Klaus Steinmetz , the racemanager of Alfa Germany in that period. The pre-owner bought the car direct from him 1975 in Settimo Milanese with the usual trouble in Italy .Means: the car was not ready at former declared date, the engine blow the headgasket at the testdrive in Monza. Luccky, that the car was not payed before delivery as wished from Autodelta!!!After reparing , blowing the next gasket one day later same place. Than, he take the car to germany and prepared the engine with his owne correctness. But the engine never reached the declared and prised horsepower of 180 HP!!! So , he race the car with the narrow head 2 valve engine without trouble and forgot the 4valve- engine.
In the last 30 years, i collected some spareparts for these typ, so in the moment , i prepare the car for my son Max, he race my other GTA 1300 with Carb-engine with succes and wish more power.

 

[UlrichGTA]

Hallo Alleggerita ,

naturely a 1300 ccm, no other 4Valve was homologated in an GTA or GTAm ! The more successfull raceteam was Stahlberg Racing from Hamburg. See the book of Horst Resch.
I bought the last pieces from him 1981 in Winterhude .

 

[Andrew]

This head sealing surface had no cam bearing oil holes that I saw. Also, the cams have oil delivery holes it looks like. Is there an external oil line to the head?

Andrew

 

[PSk]

This head sealing surface had no cam bearing oil holes that I saw. Also, the cams have oil delivery holes it looks like. Is there an external oil line to the head?

Andrew

Two feed holes behind the cam chain opening outside of the first head stud holes, I think.
Pete

 

[Andrew]

Got it, in the two recessed holes? Maybe didn't depend on the common o-rings to seal? Oil-filled cams seems more oil-tight than six o-ringed holes.
Andrew