part two...
The main caps and their hardware need little more than thorough cleaning and chasing of all threads, internal and external. Then correctly torqued and Loctited have always given trouble free service in 1300’s all the way up to 9000rpm.
The X19 sump is finned alloy and has a removable steel baffle plate. I would recommend the fabrication and installation of a windage/baffle plate. A new oil pump, and oil pump drive gear are recommended. I would also HEAVILY recommend the installation of an oil cooler, with an in line thermostat, and the pick-up, which comes from a sandwich block, mounted behind the oil filter. An ACCUSUMP would also be a consideration. Following these recommendations I feel that the oiling system would be adequate for mild competition use.
Engine bearings that are usually forgotten in SOHC and DOHC engines are for the Auxiliary Shaft.
These are full circle bearings that are supplied Ex-Fiat as a semi-finished bearing, meaning that you have to line-bore and ream up a blind hole. I sourced in Italy a company that makes these as a finished full circular bearing and have these available in standard and 10 thou under-size. These should be renewed, as excessive clearance here will adversely affect oil pressure everywhere else.
There are also the front/rear crankshaft seals and the cam/aux seals. I recommend using the best quality seals available. (Silicone or Viton) They do cost more but they handle higher temperatures and circumferential speeds than Neoprene rubber or Poly-acrylic rubber, which tend to go hard with age and temperature.
Finally on the bottom end are the flywheel, clutch assembly and the front crankshaft pulley. The brand of clutches I prefer is Fitchel and Sachs (F&S). The front pulley should be a 1300 type as it is lighter and is a slightly smaller diameter, which will slow the alternator/water-pump down. It should also be accurately indexed for TDC, BDC and for as many degrees in-between as possible.
Basic short-block preparation is certainly important for reliability and durability, but when you talk about improving the output of an engine, you primarily consider the path of the intake / exhaust gases as they dynamically cycle through the cylinder head. The Regata 1500 and X19 1500 heads are basically the same. To develop its potential in horsepower and torque this engine needs the benefit of separated inlet runners. The entire length of the inlet tract needs to be very smooth and have an even taper all the way to the back of the valve, so the cylinder head and manifold need to be considered as a single unit at this point.
Both DCNF and IDF type manifolds available. My preference would be for the DCNF type manifold, because of its much straighter ports, the IDF manifold tends to twist two of the ports quite badly. I also believe that downdraft configuration carburettors are preferable to side-drafts, for the increased torque and quicker throttle response offered by the down drafts. 40 DCNF carburettors use a maximum of 36mm venturis, which is the same size as our inlet valve!
Consistent with the improvements in the carburetion and the related increase in fuel demand, a suitable electric fuel pump will need to be mounted in the engine bay. It needs to have a capacity of at least 1.5 litres per minute. The pick-up in the tank should also be relocated to a lower position, a quality fuel filter with a replaceable/cleanable strainer is recommended, as is a fuel pressure regulator. The fuel pump position on the cylinder block will need a blanking plate. This can incorporate a fitting for additional engine breathing a point often overlooked in basic preparation.
Next to be considered are cylinder head modifications. I propose using standard sized valves. Larger valves would be nice but the additional cost of oversized valves, the valve seats and having them installed is not justified by the expected gains. Realistically more can be gained by reworking of the original valves and valves seats and match porting the cylinder head to the inlet/exhaust manifolds. 1300 and 1500 use the same valve seats/ throat sizes. The intake/exhaust valve seats can be throated out by several mm. Std throat size is only 30 - 30.2 mm intake and 26.75 - 26.95mm exhaust. Improvements can also be made to the back of the intake valve heads for flow. They should also be made as light as possible, as this has a measurable effect on the valve trains maximum RPM. Valve shim thickness should be kept to the minimum, as this also greatly influences weight. The valves can be seated very close to their periphery, effectively a bigger valve. There is plenty of scope for improvement in flow through the head, by hand finishing the intake / exhaust ports and the combustion chamber. I use German made TRW valves and valve spring sets
An improved camshaft is mandatory for real horsepower gains. A decision on which cam to use would have to be made before commencing work on the engine, as just about everything works around this component. The extent of the porting work, which carburettors are used, exhaust modifications and the final compression ratio, all need to be taken into consideration.
Hand in hand with the camshaft is a Vernier adjustable cam pulley, as it enables us to accurately phase the camshaft to the crankshaft. It’s essential to phase the cam / crank accurately.
Next to be considered is the exhaust system. If extractors are to be used, they will really need to be custom made and designed to suit the C/R, cam timing, inlet manifolding and expected rev range for optimum results. A suitable muffler of at least 2 ¼” I.D. will be necessary. I would also recommend wrapping of the extractor tubes with heat retaining wrap.
Finally, the ignition system, the standard points type ignition is not suitable for performance use. The Regata 85S uses a Marelli Plex 201 ignition system, with no vacuum advance, for the European market. It differs from the conventional point type, in that the coil trigger is provided by a four-pole reluctor (this is integral with the distributor shaft) which sweeps past a fixed stator pole. (this is mounted where you would expect the points to be) As the reluctor rotates and passes the stator, a magnetic pulse is created, breaking the coil primary circuit (low tension) via a transistorised electronic module thus generating the (high tension) voltage in the secondary winding.
This system has no electronic control over the timing of the spark but it does deliver the spark consistently and reliably. It works 100 % or not at all. The 2 components that fail, usually heat related, are the stator and lead, and the electronic control module. I feel this is the best system to use, providing 28 degrees of centrifugal advance, usually set @ 10 degrees BTDC, giving 38 – 40 degrees of total advance.
Ignition leads should be spiral wound stainless steel cored, as these minimise a phenomenon called Inductance. As an electrical pulse moves along a wire, it can induce a secondary (though considerably smaller) pulse in a second wire that is close by. This can cause cross firing leading to serious engine damage. The leads should always be separated from each other by at least 15mm, separators should be made by passing the leads through non-conductive plastic card
SteveC