6.0 V12 Engine (race)

How do you build the Worlds Fastest Jaguar?

Where do you find the parts to build the Jaguar V12 engine to power such a car?  Worse still, where do you find the money? Jaguar parts can be expensive. We may not end up with ‘the’ fastest Jaguar in the world, or the fastest C/PRO car in land speed racing. BUT, we will break the 200 mph mark, and hopefully, funds and good fortune permitting, give a good run against the current world record. The heart and soul of such a refined growler is going to be a Jaguar V12 engine, with the best parts we can find, based on the limited availability and the shallow depths of my wallet.  Here’s the story of the building of our engine which will be added to as the build progresses

There are two basic variations of the Jaguar V12 head/combustion chamber design.  The original Heron Head, commonly referred to as the  “Flat Head” design, and the more recent “HE” design. Each engine had its strengths and its weakness. To build the best Jaguar V12 performance race engine, the right decissions have to be made on which platform and components to use and build on.

When Jaguar developed the HE engine, they were desperate to improve the highway fuel efficiency of the early V12 flat head engine.  The end result of Jaguars efforts was the development of the HE design, used from 1981 on.  The HE (High Efficiency) design, recessed the exhaust valve deep into an oval shaped combustion chamber in the head which is where the spark plug was located.  As the head now had a combustion chamber, the HE design used a flat top piston to compensate and bring the compression back up.  On the compression stroke, intake gasses are forced into a vortex, swirling into the  combustion chamber around the exhaust valve.  Jaguar has continued to develop and improve both performance and efficiency in engine design to compete in todays high efficiency/performance market.

This creates a much improved environment for burning lean mixtures at higher compression, resulting in the improved fuel efficiency Jaguar was seeking.  While the resulting production HE V12 cars power compared well to the best production flat head engines, the HE design limited the power potential to about 400 b.h.p.

The original head design from 1971 to 1981 is referred to as the ‘Flat Head’ design.  This design has the intake & exhaust valves alongside each other in a flat combustion chamber area.  One might consider this early design as a reversed hemispherical design in that the combustion chamber area was a hollow bowl top piston.  This design had performance benefits as the valve area was unobstructed which allowed excellent flow capability.

The problem with this design was the part throttle fuel efficiency.  But, when the objective is focused on high performance and racing V12’s use the early flat head design.

In order to make the most power from the earlier flat design heads, improving the breathing capabilities by enlarging the valves is mandatory. The largest valves you can fit into the stock flat head casting is 2″ on the intakes, and 1.6″ on the exhaust.  Any more than this and the valves run into each other. Naturally, porting and polishing to allow the air to get to and from the valves is a must. But again, there are always limits, and in the porting category, wall thickness runs out before you are able to make monster ports, although you can get a reasonable size out of them.  Fortunately, the speed gods have smiled upon me.  When it comes to the heads, it’s hard to get luckier than this.   Jaguar had built out the back door a very limited number of special casting performance flat heads specifically for the Group 44 race team.  It is with these heads, that Group 44 was able to make over 800 hp with their best engines.   I have been blessed with a set of these  irreplaceable heads for on top of the block. These special castings pushed the flat head as far as the design would allow, with much larger valves and ports larger than a stock casting could facilitate.  Sealing the heads to the block is handled by 0.80 thou solid copper head gaskets.

For our purposes, we need to get well past the 400 horse mark if we want to have any sort of shot at the current record of 234 mph.  So, we will combine the best of both worlds, or engine designs in this case.

Engine Specs: Race

Type: OHC 6 litre V-12

Displacement: 6092 cc / 371.8 cu in

Bore x Stroke: 90.0 x 78.5 mm (3.54×3.1 inches)

Compression ratio: 16 : 1

Hp @ rpm net: to be determined

Kw @ rpm net: to be determiend

Torque @ rpm lb/ft net: to be determined

Fuel Injection= 6 –  2bbl 45mm TWM throttle bodies

The base engine block assembly selected for the competition 6.0 liter engine will be a 1994 V12 which was essentially the most refined of the production 6 liter line.  This is an aluminium 4 bolt main block with a forged crank shaft, with the added benefit of the full flow oiling system of the later design.

Now remember, the flat head design engine used a recessed bowl top piston, while the HE design used a flat top piston.  Combining the flat topped HE piston with the Flat Head design heads results in a compression ratio of 16:1.  This compression will be required in order to make power in the thin atmosphere found at the altitude of the Salt Flats.

To replace the stock Jaguar connecting rods with something more capable of handling the few extra thousand rpm the engine will provide, required going to the performance aftermarket to meet the demands.  CROWER forged ‘Sportsman Premium’  model connecting rods on a Chevrolet forging are custom machined to specification with full floating wrist pins and using a small block Ford rod bearing.

SPORTSMAN ® First introduced back in 1987, the Crower Sportsman rod was the original high performance stock replacement rod. Features traditional thru-bolt and nut fasteners for stock legal classes.  All Sportsman aircraft quality rods are forged using dies, dedicated to a specific length (5.7″/6.0″). This forms a more uniform molecular grain flow for a stronger, more reliable rod than other brands using one die for several lengths, then cutting to size.Includes 3/8 – 8740 bolts and nuts rated to180,000 p.s.i..

VALVETRAIN, cams, springs, retainers

In the camshaft department, the decision was made to go with a known and proven cam, the XM-2 grind from Isky.  The XM-2 grind is considered a ‘combination’ cam, having the characteristics to provide great top end breathing and performance, while retaining a reasonable level of bottom end characteristics with a .404 lift and 2580 duration

When building a high rpm race engine, you want to upgrade from steel to titanium valve spring retainers.  You gain speed and power, because titanium retainers are up to 50% lighter, and three times stronger than steel reducing your reciprocating mass, creating a faster-revving engine and reducing the risk of valve float. Being stronger than steel these retainers will hold your valve train together at high rpm.  These titanium retainers are CNC machined from the finest 6AL 4V alloy and heat-treated and processed to a stringent tolerance for maximum accuracy, performance and reliability. Titanium components are available for most domestic engines. If you can’t get what you need over the counter, you can make it, or have it made. One source is Titanium Metal Supply to purchase surplus titanium for industrial or hobbyist needs.

FUEL INJECTION, throttle bodies

Fuel Injection Systems and Accessories

We’ve selectedIDF style throttle bodies from TWM.  These are compact, downdraft, two barrel units  They are available in 40, 45, 48, 50 and 55 mm bore sizes. For use on the 6 litre, we’ll be using the 45mm units.  TWM machines all four of the injector pockets during manufacture, supplying plugs for the unwanted pockets and removing the unwanted rail brackets at the time of ordering.  Air horns, also known as velocity stacks, will be going on our bodies as this is a race, not street application.  Here’s what a full set looks like sitting on top of a V12, in this case, with filtering for the street.

You’ll soon see what they look like with the stacks on top of our engine.

Engine Management System

We’ve selected the TEC³  system which represents the current in state-of-the-art fuel injection and direct ignition control integrated into one package. The TEC³ is a PC-programmable engine control system featuring   Windows-based tuning environment.  The benefits of a distributorless ignition system that not only is infinitely adjustable, accurate, and powerful, but also gives you improved firewall clearance and freedom from all those ignition amplification boxes. If you are running an aggressive profile camshaft, idle control has always proven to be problematic for engine management systems, but not for the TEC³.  For ultra high output engines, the sophistication and power of the TEC³ system simply out-performs other production and aftermarket systems. With full control of the engine over all possible operating conditions,  new rev-limiters with Triple Smooth technology, and On-Board Data Acquisition, the TEC³ gives you Total Engine Control.

The TEC³ Engine Control Unit

The new TEC³ ECU incorporates the winning features of the previous TEC-2 system while adding an abundance of new features and a powerful new processing platform. Electronic Fuel Injection (EFI) control and patented digital Direct Ignition control is standard hardware for every TEC3. The anodized, laser-etched ECU with waterproof OEM style connectors and harness may be mounted under the hood or in the passenger compartment and will activate separate multi-coil DFU (Direct Fire Units) mounted adjacent to (or on) the engine.

Standard features built in to the TEC³:

New On-Board Data Acquistion

SAFETY BELL HOUSING

No matter what transmission you select for your application, you have to get it connected to the engine. There are after market manufacturers of complete conversion kits which will make your life a lot easier. But, if you are going racing, the odds are you will need components meeting the SFI standards. This means you may have to scrounge, modify or build what you need to piece it together. When it comes to the bell housing, we will use a Lakewood bell housing, also known as a scatter shield. These SFI certified housings are hydroformed from 1/4″ steel plate so that if you disintigrate a clutch, the odds are, all the shrapnel will remain within the confines of the housing, rather than seperating your feet from your legs. Fortunately, the later engine design, shares  alignment pin locations with the Chevy bolt pattern. It’s easy enough to modify the remaining holes to match up by drilling the bosses and notching holes, thus solving your problem. An additional bonus is that these housings can even be found used at swap meets etc. for a pretty cheap price thus keeping some of those precious dollars in your pocket.

Here’s a picture of the modified housing bolted onto the engine.  You get enough of an idea to determine this works with a little effort.

Here you can see you must notch the housing to clear the starter nose, and provide access to the top starter mount bolt.  Yes, it’s a bit of a hack job at this point, but, it was just the removal of material to obtain clearance.  Once things fit, you can close the housing up to cover the openings, and leave access to the bolt as required.  When finished, it will look factory.

FLYWHEEL, CLUTCH & PRESSURE PLATE

For connecting the power to the transmission, we’ll be using a custom billet flywheel and a 10.5″ diaphram pressure plate from RAM .  RAM Products stand out from other manufacturers with loads of features other companies either don’t have or are just adding.  Perhaps more importantly, they will work with you to find or create the solution you need.

CUSTOM BILLET FLYWHEEL

Reducing the rotating mass is HUGE in getting the most out of your engine.  Or perhaps I should say in not wasting the power you’ve got.  Going to a billet aluminium flywheel does just that.  Not all billet flywheels are not created equal! Make sure you are getting the features you pay for. RAM billet steel and aluminum flywheels are fully machined and assembled in house. That means when you get your flywheel, it is already surface ground, already balanced, and ready to install out of the box. A key feature of RAM aluminum flywheels is the steel insert. A flywheel insert must have enough mass to wick heat away from the clutch without distorting. RAM uses a .250-inch thick inset that is riveted in before the flywheel is surface ground. This assures a parallel friction surface with no run out, and enough material to adequately wick the heat while maintaining flatness over time that thinner inserts simply cannot do. All RAM billet flywheels are SFI certified.

 PRESSURE PLATE

Safety

You only need to know one thing to determine the general safety of a pressure plate. It must have a ductile or malleable iron pressure ring.  Most replacement pressure plates are gray iron and subject to bursting at elevated RPM. (Read: EXPLODING at high rpm.)  If your parts supplier is not able to confirm his product is ductile iron and meets industry safety standards (SFI), STAY AWAY FROM THAT PART!  Ductile or malleable iron is required for SFI materials certification. It must meet 60,000 psi tensile, 40,000 psi yield, and 10% elongation specifications to pass SFI testing and assure you maximum safety.

Performance

The pressure plate is the third element of the clutch system. (1 Flywheel, 2 Disc, 3  Pressure Plate.)  The most important issue for you is that the unit you are purchasing actually has the pressure increase you need for your application. If you look at the pressure plate listings under COMPONENTS on the RAM website you will see the pressure ratings for pressure plates. These listings are static pressures. That means this is the pressure load supplied at all times regardless of the engine rpm.  If you have built up an engine, and fail to use a cluth/pressure plate up to the task, you WILL be burning out discs and replacing assemblies on a regular basis if you are putting any of that horse power onto the ground.  Do it right, do it once!

THROW OUT BEARING

I wish hydraulic clutches had been invented years ago, when I was still struggling to create all the brackets, levers and linkage to get a cluth to work smoothly. Thankfully, our clutch pedal assembly is configured for hydraulics, we’ve selected a self sligning race performance throw out bearing # 82870 by HOWE, available from most performance suppliers.  We grabbed ours online from Summit Racing.  You get what you pay for.  This bearing is fully serviceable, and all parts available from your favorite supplier.  If you haven’t been down the hydraulic road before, it doesn’t get much simpler.  These hydraulic throw outs are a small precision hydraulic ram, bearing, bleader, adjuster, all rolled into one unit.  Slide it onto the transmission, a little shimming adjustment connect a hydraulic line from the clutch master, and you’re pretty much done.

TRANSMISSION

For those following this aspect of the build, and probably thinking I’ve abandoned ship, or parked my butt in a recliner.. I’m still here.  But, as things have proceeded, I now find the need to get the engine onto a stand, to both get it off the floor, and to facilitate assembly and set up of the associated systems prior to installation in the car.  With that need, I am currently detoured with another project, the building of an engine test stand, listed under the projects page.  So, if you get bored, jump over to that project to see how things are proceeding.  Once complete, unless something else gets in the way, this article will start to move forward again, so don’t run away.  The writing of the article is somewhat behind where the engine is in reality, as is the engine stand article.  But, if you pay attention while viewing the live shop web cam, you might catch a glimpse of the engine, bolted into the stand.

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