348 crank in 308/328 motors

Sounds interesting, and I guess it depends on what generating some serious power translates into, as a stock 348 only puts out 300hp.

 

There is a lot more to making hp than just increasing displacement. Normally, the only thing boring or stroking an engine does is increase the torque and shift the peak down, the hp then stay about the same. To increase hp, the flow needs to be increased, normally by porting and increasing valve size...but ferrari didn't leave much room for that...300ish.

 

Mark is quite right. the 348 heads have larger valves on both intake and exhaust, and a better port design, thus provideing the necessary flow to feed the larger motor. I would not tend to think that the output would be what one wants, and IMO would not equal the 348 HP output.
A couple of years ago, I did the project feasability analysis on the 4 litre motor, and my conclusion was that the Maximum safe bore was 86mm due to the thin sealing area between the cylinders. The 3x8 blocks that I measured calculated out at a 94mm bore centerline, so there just isnt much room to seal when you bore that far over. 86mm would be a stretch, due to the total gasket seal area of 8mm total. The use of 88mm sleeves only leaves 6mm , or 3mm (.118") wall thickness per sleeve. Not enough to O ring the motor succesfully to insure seal. Then there is the matter of feeding that large of a motor, with ports and valves that were designed to work with 3 litres. IMO, the increase in output will never be as expected, even if it could be successfully run. Then there is the matter of cooling. As we know, the 3x8 motors tend to be a problem in that area, especially when modified. This motor is designed to have the coolant flow between the cylinders, closeing that off in the gain of more displacement seems a bit counterproductive.
To go to such lengths to gain power seem a tad contradictory, when in reality, Belt Driven superchargers, such as Mark's stunning example, or the addition of turbo fed induction would give the same if not more power without the obvious expense of all that machine work.
I would be suprized if the 4 litre motor lasts for any appreciable length of time, JMO.
Kermit

 

good post.

 

I agree Charles, that is what my calculations came out to as well.
I would not be suprized if that combo turned out to be a real screamer, with the stroke remaining the same, one would not lose RPM capability, and would be even more oversquare. Bore centerlines being what they are, the 85mm sleeve does leave a bit for coolant flow, so that issue is not the difficult part.
Quite frankly, that would be my choice if I were to go with an oversize bore. Aftermarket sleeves ( Darton preferably) would be a preferance, as opposed to the aluminum Nikasil lined ones due to a far more rigid sleeve resulting in a superior seal.
IMO, that much of an increase in total displacement would produce more power than stock, especially if combined with better cams, and porting, induction improvements, etc. An aftermarket Aluminum radiator would help in handling the heat issue, so it would be a viable, no doubt responsive unit. There is a lot of differance between 3.3 Litres, and 4 Litres however, and that is what I was speaking to.

 

This post is in response to the insinuation that a 308/328 motor cannot be reliably increased in displacement to 4-liters. For those who continue to hold on to this misguided belief, I would direct your attention to the following website:

http://www.nicksforzaferrari.com/forzaferrariwebsite1_029.htm

Not only is it possible, it has been done. It was first successfully engineered in the late 1970’s by a former Ferrari factory race mechanic, and substantially refined with state-of-the-art technology by others with decades of race and engine design experience.

The good news is that a high torque, large displacement, eight-cylinder Ferrari engine, is a legitimate alternative for anyone that currently owns an either a 308 or 328. The express purpose of this engine program is to create a 308/328 Ferrari that is truly a contemporary “Super Car”, which also possesses the ability to be a daily driver. It cannot be overstated that the 4-liter engine program is specifically designed to eliminate most, if not all, of the maintenance nightmares referenced daily on this chat line. A Ferrari shouldn’t be a piece of art that is simply unveiled during a few sunny days each year. These cars should be driven…driven hard, and maintained at reasonable service intervals with a minimum of cost. It is not only a noble goal, but also the inevitable outcome of this project.

In should be noted that this thread has misrepresent the current state of art of engine development.

1. Specifically, one post proposes an arbitrarily limit of an 86 mm sleeve diameter. Why make such restrictions in sleeve thickness, when BMW and Ford are running race tolerances that are a fraction of that specification without problems? If they can run at what would be the equivalent of a 89 plus mm sleeve, why not a 308? The key to running thinner sleeves is directly related to the techniques employed to machine the block and sleeves for the type of head gaskets used. These machining techniques are not readily available at a typical machine shop.

Also critical to the success of this design is the use of the highest quality studs and fasteners. The 4-liter engine program currently makes these units available to the general public as a stud kit engineered to aerospace standards for less than replacement cost of the OEM equivalent. There is no justification to reuse critical hardware that has been heat cycled as often a 308/328’s head studs. The bottom line is that a 308/328 can reliably use an 89 mm sleeve without blowing head gaskets.

2. Why restrict Ferraris from using the same technology that is being successfully being used in Corvettes, Vipers, and Hondas? Some of these engines are producing in excess of 1000 hp. In short, if someone still wanted to super or turbo charge a 4-liter motor it would be a superior candidate than that of a stock block 308/328. Frankly, the question is not if it can be done, but rather how is it currently being done? Most of the secrets to doing this correctly are proprietary to the 4-liter program.

3. If the only modification to a 308/328 engine is the addition of a supercharger then this well intended effort to boast hp will only exacerbate all of the other weak links in these motors...and there are plenty of them. The 4-liter has no weak links. Every mechanical system has been carefully evaluated and if necessary re-engineered.

4. Concerns voiced regarding head gasket sealing fails to take into consideration the use of MLS style head gaskets in conjunction with perfectly machined decks. The actual quality of machining on the 4-liter motors cannot be overstated in comparison to a stock rebuild. Machined O-rings in the deck are not necessary, nor a move in the right direction.

5. Sleeve design and the use of contemporary O-ring systems in the cooling should not be discounted before they are understood or examined. Cooling this motor is critical and to this end there are several upgrades in the cooling system of the 4-liter. I would simply refer you to the diagrams in Nick’s website.

6. Simply adding displacement by making the engine even more “over square” does not address the 308/328’s obvious absence of torque. The 4-liter engine remains over square while lengthening the stroke to provide a lot more low-end torque without sacrificing hp. Darton supplies sleeves to most of the top fuel and funny car teams. For the readers that don't know what a top fuel or funny car is, you can mention that these engines produce close to a thousand horsepower per cylinder. That should eliminate any doubt about the sleeves.

7. Darton Sleeves have been previously referenced in this thread. It would be unfair not to acknowledge that the sleeve in the website is a blank Darton Sleeves after extensive machining and that the machinist is same person that currently doing the Vipers, Hondas, LS1’s and Ferraris. Darton supplies sleeves to most of the top fuel and funny car teams. For the readers that don't know what a top fuel or funny car is, these engines produce close to a thousand horsepower per cylinder. That should eliminate any doubt about the sleeves.

For more specific information, I would suggest that you contact Nick directly.

 

I doubt it is as easy as swapping the crank, the pistons and rods. (and gaskets)

Is it? (in reference to the original question, not the 4L question, which requires much more 'tinkering')

 

Actually the 4-liter engine program will be as easily as either ordering a completely assembled long block or a laundry list of performance parts and custom machined pieces. It will be no more difficult than for those that are currently doing similar things with Vipers, Corvettes, and Hondas.

All subsequent machining will be done on state of the art CNC equipment, so each engine will maintain the same high level of professionalism as the prototypes.

If you have more questions, call Nick.

 

dyno sheet??....I just find it hard to believe you are getting 50% more air through the heads to feed the thing...10% or 15% I'd believe, but 50%??...sound like a cool project though.

 

Mark, while I commend your goals, I must stand quite firm on the issue. While I was doing the preliminary project feasability study as a subcontractor for the Forza, I spoke at great lengths with the Darton people. I recall very clearly their policy on wet type liners was a wall thickness minimum of .150".
This was one of my criteria for limiting the bore diameter of the concept. Now that it has been reduced to .118" on the mating sides, the further reduction I see from the pictures seems to have been yet further cut to allow the flow of coolant. A minimum cut to allow any volume of flow would to me be at least .030" per liner, allowing a total flow area consisting of a gap .060 wide, marginal, but perhaps functional. However, that leaves the wall thickness at .088" in the area that is exposed to the greatest pressure upon combustion. To compound the liners problems, the use of the stock length rod will result in far greater side loads the piston places on the walls.
Rather than go on, I would suggest for the good of all, rather than directing questions onfurther information to us calling Nick, why not invite him to answer the questions on the forum?
BTW: I did in my research find that Ferrari did a prototype vehicle with an actual 4 litre motor. To the best of my recollection, it was based on a F117 series motor not a F105 or 106.

 

Charles, back on topic as well, can you provide more details? I would love to know. When I do it though I would like to put higher quality gaskets in as well. It seems like a good upgrade to do when the next major rolls around....

 

Power increase numbers? Pistons and CR were changed as well?
Very interesting.

 

You say the power increase was very substancial, do you know what the numbers where? I just don't think I've ever seen a displacement increase alone add much hp, if there were other changes as well, then the the numbers should be compared to a stock stroke engine with similar changes. The stock compression is pretty low, increasing the stroke will increase the CR, I suppose that will add something, 10-20 hp maybe. I guess just pulling the CIS off gives you something like 30-40hp, adding cams and pistons will bring you to 300-320hp, add some port work and it's 320-340 maybe.

 

Mark, CIS? Do you mean the stock ignition system? or stock emission system?

 

348s have the flywheel and clutch on the back of the gearbox. I am not sure that there is a manner to fasten a 328 flywheel to the end of the 348 crank?

 

I just can't see that a 2 mm stroke increase would increase the horsepower at all and would increase the torque an insignificant amount. Numbers gentlemen, numbers!

 

The stock mechanical fuel injection system. The air metering valve is very restrictive to air flow, so replacing it with EFI or carbs adds quite a bit of hp. Also oncew the stock injection is gone, more aggressive cams can be used.

Sorry. Back on topic. Do you know if the bore centers are the same? journal sizes? A 348 manual should have that info which will tell you if it is possible, it would be a good start to confirming what you were told anyway. You would need custom pistons with a raised wrist pin or shorter connecting rods at the very least. I do truely believe you could hit your 320 hp goal pretty easily with your 3.2 liter engine. You already did the EFI conversion so I'd be surprised if you're not at 290 or so right now. Add a set of cams and you should be pretty close I would think...but I guess there is no replacement for displacement, it sure can't hurt.

 

I hear tale that a rabbits legs can be swapped out for a turtles legs,
and that all you have to do to make that old turtle go faster is fuse the bone from the rabbit to the turtle's joint ends.

Hey I wonder if I gaff the tendons of a cheetah on the the rabbits legs,
do you think it will be faster than....

 

Alhough I have never had the opurtunityto study that particular block (yet), I can tell you I have peronally dropped a set of 348 heads onto a 308 4 valve block. They slid home like they belonged there, so I would deduce that the bore centerlines are the same.
HTH
Kermit