The (one and only) '0846' Debate Thread

Same engine block and cylinder liners/pistons can actually have different dispacement if the crankshaft/connecting rods are different. The swept volume may come with the piston hub variation, not only with the bore change. On a different note, modern diesel engines ( which implicitely are ALWAYS turbocharged ) do adopt sequential ( multisprayed in fraction of seconds ) high pressure direct fuel injection which allows for efficient combustion. By pairing high pressure , cooled air feeding ( via multistage turbocharging/supercharging + intercooler ) with high pressure fuel injection ( +2000 bar ), the specific power output of a diesel engine has virtually no limit but the mechanical stress of the block itself. Due to gasoline phisical properties like self-ignition point , that cannot be done with petrol engines, as the charge air pressure ( i.e boost ) is limited. Can elaborate and provide detail /examples on a separate thread if it may appeal to the f-chat community.

 

Very interesting. Add cupping or dishing the tops of the pistons and you've got it. Making the changes you and Krowbar spoke of is a lot less costly than casting a new block.

The R 10 will be very interesting as well.

Best

As an aside are you in the automotive Bussiness in Turin? I'm working with pf on a project that I think fchatters may find interesting and travel there often. Turin is a wonderfull city There will be a small hint of what we're up to in the pf TV video that will be presented at Awards Giving of the upcoming Olympics.

 

FYI, the cars ran both with and without the superchargers. Fusi, the "Alfa bible" also says 4 cars, but there only appears to have been two built, chassis numbers 412151 with motor 412037 and 412152 with motor number unknown (one car is in Schlumpf, but there is an overstamp on the motor number, making it impossible to see what it was). The car that was rebodied by Vignale and ran in the 1951 MM was offerred in the early 1960s in Road and Track, and there was also an article around taht time about the car being stored at an etceterini garage in Milan and being driven through the city. The car was offered to Henry Wessels for around $10,000, but he turned it down. It disappeared in the mid 1960s, but has been rumored to exist (in part) in Argentina. I have talked to all the Alfa people I know there and no one knows of it (or isn't talking). I mentioned this to Bill Noon a few years ago, when he had one of the Alfa 12c37 GP cars.

 

Cal Morr,

Cupping and dishing pistons will alter compression ratio if the bore or stroke are not altered. Installing liners which provide a narrower bore but use the same crankshaft will alter the bore stroke ratio considerably. Generally, I agree that the heads would be interchangeable, especially considering the level of understanding of swirl and tumble back then.

Altering crankshaft and connecting rods + new pistons with lowered mounting points + cylinder liners makes sense, but still requires a disassembly. If we are saying that the same block can be built up into engines of different displacement then, I agree. Altering the displacement of a given engine still has me confused - seems like too much effort - not a quick change.

On the topic of new technologies: CIDI (Compression Ignition, Direct Injection) combined with an air pump (turbo or supercharger) does eliminate the displacement issue, but I do not see how it bypasses the restrictor plate issue (you are not suggesting supersonic intake flows are you?). By the way, SIDI (Spark Ignition, Direct Injection) still has a lot of promise for running gasoline engines in a stratified mode at part load - if they can overcome the teething pains.

Regards,

Art S.

PS. A separate technical thread would be interesting but unfortunately, I rarely leave the vintage section and probably would not find it .

PPS. Jim G. if you are casting a batch of blocks, why not cast one more? The engineering and design effort is the majority of the cost and you can't reuse the guts anyway.

 

On the topic of new technologies: Six Stroke ..... yes, that's what it's called.

The following is an simplified description of the combustion process of the Beare Head, and is designed for non-technical types.

INTAKE

1. The intake stroke happens when the piston is on its downward path with the intake valve open. This action creates suction, drawing atomized fuel, in this case gasoline mixed with air, into the combustion chamber.

This is exactly the same action when liquid is drawn into a syringe.


COMPRESSION

2. The compression stroke happens as the piston begins its upward stroke with all the valves in the closed position. This compresses the air-fuel mixture causing it to become more volatile, or explosive.


IGNITION

3. The power stroke begins at a critical moment, just as the air-fuel mixture is at its most compressed. A supercharged voltage is delivered to the spark plugs from the ignition coil, at which point it ignites the fuel mixture. The valves in the engine are still closed during this period. Thus the explosion forces the piston down to turn the engine's crankshaft, delivering the power via the gearbox and clutch to the driving wheels.


EXHAUST

4. The final of the four strokes, as you have not doubt guessed, is the exhaust stroke.The piston is now on its second upward path, and the exhaust valves are now opening, allowing the spent gases to exit the engine via the exhaust pipes. At the top of this stroke the exhaust valves close, the intake valves open, and the whole process repeats - quite rapidly.

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ArtS,
The question was around obtaining different displacements ( swept volume ) by same engine bloc, in the topic 3.3L vs 4.0L. This is technically possible just playing with the cylinder bore/hub arrangement. Compression ratio does not change with the displacement but relates to the combustion chamber geometry ( cylinder head and top of piston ) . So that by just looking at engine outside you would not feel or see the difference, you need to actually measure the volume of the cylinder. It means also that by just looking at the car outside you cannot know if is the 3.3L or 4.0 L engine inside unless you have evidences which proof the displacement. In the racing era of the`60thies engine dispacement had no upper limit for the category SP ( Sport & Prototypes ) so that the teams could set-up the most appropriate engine to the different races in same car body. Typically light and "torque" engines for Nurburgring, Targa Florio, Brands Hatch and larger "power" engines for Monza, Le Mans, Spa Francorchamps. In the P3/P4 case the 4.0L engine had also different combustion chambers ( see Wax`s post ) so that feel the head outside should have been different as the 3.3L version.

 

well said. a pontiac 350, 389 ,400, 421, 428, and 455 used the same block castings. the crank, rods, and bore diameter is what changed the motors from mouse into monster. several of the head castings are interchangable, but the results are not always favorable.

 

I agree. Logic suggests that Ferrari (as a manufacturer of engines) would simply build another engine, and then swap them over. If you've already got 3L or 3.3L engines sitting around then why bother rebuilding any engine as a different type/size? And as no one has provided any evidence that 330P4s ran anything other than 4.0L engines there's not much point.
Nathan

 

Yes, but have we proven that the P3s or the P3/4 never ran a 3.3 liter??

 

Art

"Altering crankshaft and connecting rods + new pistons with lowered mounting points + cylinder liners makes sense, but still requires a disassembly. If we are saying that the same block can be built up into engines of different displacement then, I agree. Altering the displacement of a given engine still has me confused - seems like too much effort - not a quick change."

Art you of all people should realize why they had to use the same block.
The only block that fits into a P3 Chassis without modification is a 216B P3 block.

If you want to fit a P4 block into a P3 chassis you have to do a bit of cutting. Also if you fit another typo block/heads people could tell by looking at it and they may have not wanted people to know what they were up to.

They very well may have used spare blocks. That isn't the point. The point is the motor can be built up various ways and still look the same on the outside, assuming you know how to do it and don't use sandwich plates...

 

Can someone please post a list of all the p3/4 p4 sn#s and what the difference between them? I am getting confused. I was reading the march 2005 cavallino about 0856. They all look the same, but I don't know which is which.

 

When?

 

Hi Stu
Until this came up on FChat no one had ever suggested that the P3s or P4s ran anything but 4.0L engines. Therefore the onus is on those suggesting something new/different (if that is what is happening) to prove that everyone so far has been wrong.
So far there have only been theories about 275P3s (apart from an obvious captioning error). So let's have facts. Which car(s), which race(s)?
Nathan

 

off the top of my head

0844 P3/412P/412P Can Am/412P
0846 P3/ P 3/4
0848 P3/412P
0850 412P
0854 412P
0856 P4
0858 P4/ 350 Can Am
0860 P4/ 350 Can Am/ 350(?) P4

Wayne Sparling said that some of the above were run as 3.3 liters at some races where fuel economy was more important than high speed. Fact.

Both the P3 block and the P4 block can be set up with different displacements.
Fact.

0846 and the leading 2.2 liter Porches were on the same refuling stop at the 1966 Targa Florio just before Bandini flipped. Fact.

The Targa is a low speed/long lap race where fuel economy could matter. Fact.

The caption speaks for it's self. "275 P3" It may be incorrect but it is quite clear what it says. Fact.

Facts are what they are. No more. No less.

 

Thanks Jim!!!!

This helps a lot!

Are they all still around? (**NOTE TO OTHERS - THIS IS NOT TO DISPUTE JIM'S CAR- I AM JUST WONDERING ABOUT THE LIST ABOVE WHICH CARS ARE STILL AROUND)

 

Yes they are all still around.

 

Thanks again Jim.

 

Correct me if I'm wrong, I'm trying to go from memory.

0844 = Leventis, UK
0846 = Jim G., USA
0848 = Perfetti, Switzerland
0850 = Yeaggi, USA
0854 = Jim G., USA
0856 = Stoll, Canada
0858 = Medlin, USA
0860 = Bardinon, France

How'd I do?

 

Nathan:

As I said before I AM NOT a Ferrari expert. I know some stuff, especially about the pre-1960 cars, but my area of expertise is "etceterinis".

I am not sure the photo caption is an error. I believe it IS possible that P3s, the P3/4 and even the P4s ran with 3.3 liter engines. I simply don't know.

 

As Spice says you're a keeper.

 

She like the comment.

All the best.

 

While I am not aware of a P3 ever running a 275 engine, it is possible, although note reflected in the recorded entry and results information. Beginning with the 250 P series (0810, 0812 and 0814) engines of different displacement were used and swapped between races. The same was done with the 330P's (0818, 0820 and 0822), swapping between 330 and 275 displacement depending on the race. The spare units carried Roman numerals (I, II, III, IV) As ArtS notes, changing the internals is messier than swapping the entire unit. I would expect that the later cars continued this pattern of having more than one engine for each Chassis serial number like the earlier cars did. This is illustrated in the pictures of the Ferrari team changing a P4 engine at LeMans with the tried and true engine hoist of four guys, a 4x4 and a piece of rope.

 

This is very interesting. For example would the spare engine be stamped (0818 I) ?

 

I can't see a specific engine being numbered for a specific chassis, but almost anything is possible with Italian cars