What engine maintenance should I perform while the engine is out of the car?

The engine in my car ran very well, the only thing done to it was a new Holley 600, and a performance alloy manifold, recommended by a well known de tomaso expert, who has been a fountain of knowledge. I have removed the engine, to refurbish the engine compartment, so what would you do to a 40K mile engine before putting it back, it didn't smoke, and oil pressure was good. The clutch release bearing is shot by the way to give some idea of the only fault I have found so far.

please bear in mind that I don't want to improve power at all there is more than enough for my ability already, but cost is a problem the Money fairy doesn't come by each month anymore with a bag of gold but the Pension is the amount that is available, so I have to be a bit careful so what are the major points I should be looking at on a 40K mile motor to maintain performance for a further considerable amount of miles please, best Peter.

I am retired, living on a fixed income, I am completely sympathetic with the "money fairy" comment.

First of all its good to know that Peter's Pantera is a 1972 Pre-L, and if equipped with the original engine it should be a 1972 Cobra Jet, which outside of the 351 Boss version, is the best short block to start with. It has 4 bolt main bearing caps, flat top pistons, windage tray, Cobra Jet camshaft, etc.

Any US manufactured Cleveland engine is considered to have 4 weaknesses:

The lubrication system under-lubricates the crankshaft journals (especially the rod journals), it has compatibility issues with some tappets, and it tends to over-lubricate the valve train.
The connecting rod big-ends fail
The valve heads break-away from their stems
The cylinder walls crack under severe operation

I shall recommend remedies for the first 3 weaknesses. To remedy the fourth weakness requires replacement of the OEM pistons with round skirt pistons; it is less of an issue for you or I since our engines are operated below 7000 rpm, they are operated below 10.5:1 compression, and they are operated below 500 horsepower. A 40+ year old Cleveland also has a bunch of aging rubber parts. I'll cover those parts, plus I shall suggest three improvements in the engine's thermal efficiency.

Ignition

If the engine still has a breaker point distributor consider a Duraspark I or Duraspark II upgrade. Either ignition has more spark energy than a breaker point ignition, and they allow a wider spark plug gap. They improve thermal efficiency which you shall feel as smoother and stronger low rpm performance. Plus the engine's performance does not degrade with use because there are no more points to periodically adjust.

The Duraspark II ignition was merely a new name given to Ford’s original breakerless ignition which was phased into production during 1973-1975. It performs identical to a breaker point ignition in terms of having "fixed dwell" (dwell is the degrees of crankshaft rotation allowed to charge the coil), except it does not need periodical adjustment, and it has more spark energy (wider plug gaps are possible). Painless Wiring offers an aftermarket wiring harness for the Duraspark II ignition, thus it is a "plug & play" installation.

The “California-Only” Duraspark I ignition of 1977 to 1979 was Ford's fist high output ignition and the first Ford ignition to utilize "dynamic dwell". Dynamic dwell attempts to "perfectly" charge the ignition coil at any given engine speed by varying the amount of crankshaft degrees over which dwell occurs (based upon engine speed). Thus the time period of dwell (coil charging) remains constant from idle to the rev limit. Fixed-dwell ignitions overcharge the coil at low rpm and under-charged the coil at higher rpm. Dynamic dwell allowed Ford to use a higher output ignition coil, since the coil was never operated under a condition of being over-charged. Although it was not as accurate of an ignition as the TFI and EDIS ignitions that were introduced in the 1980s and 1990s, it was better performing, and had far higher spark energy at any engine speed than anything that had preceded it, including the Duraspark II ignition. Unfortunately an aftermarket wiring harness for the Duraspark I ignition is not available. The Duraspark II wiring harness available from Painless Wiring can be modified for Duraspark I applications, but this is only recommended for folks capable of understanding and performing those modifications.

The proper ignition timing for factory iron heads mated with flat top or dish top pistons is 16° to 18° initial advance, and 20° centrifugal advance which is “all-in” by 2800 to 3200 rpm, which adds-up to 36° to 38° total advance. Vacuum advance should be limited to 10° and connected to ported vacuum. Although some 351C engines can utilize more than 16° or 18° initial advance, the engine becomes too difficult to crank when it is hot if the ignition is set for more initial advance. If a Ford distributor is utilized a 10L/15L advance plate (installed in the 10L position) and replacement centrifugal advance springs shall be required. The MSD #8477 distributor makes a good substitute for a Ford Duraspark distributor; it employs a Ford magnetic pick-up, and is thus compatible with the Duraspark ignition modules.

The Components Easily Accessed

The coolant system’s design is very modern, it performs great when the correct parts are used. Make sure the correct 351C specific thermostat is installed (Robertshaw 333 series), and that the brass restrictor plate is installed below it. I would also recommend the small water pump pulley available from SACC Restorations. The pulley spins the pump about 10% faster, speeds up coolant flow, which is one of the Pantera's design issues.

This is also a good time to replace the fuel filter and any rubber hoses associated with the fuel system.

Now is the time to inspect the flywheel and ring gear. If the ring gear is chewed-up then it will need replacement. If the flywheel’s clutch surface is flat but has the typical grooves and ridges, and can be cleaned up by removal of no more than 0.045” material, then a simple resurfacing may suffice, especially if the motor will only be used "conservatively". However, if the flywheel shows signs of stress cracking or heat checking, if it would require the removal of more than 0.045” material to clean it up, if it is warped or has excessive run-out, then the flywheel shall need to be replaced.

There is a pilot bearing installed in the rear of the crankshaft, now is the time to replace it.

All but the 351 Boss crankshaft dampers were too light for performance engines, and they were also unbonded. This means neither the damper's hub nor its outer ring were bonded to the rubber sleeve sandwiched between them. As the damper ages the elasticity of the rubber sleeve dimishes. The unbonded ring will eventually begin to move around on the hub, it may slowly spin on the hub in such a way that it is no longer clocked properly. This impacts your ability to properly time the engine, and in some cases it will throw-off the engine's balance (some dampers were balanced on the outer ring). The ring may also walk forwards or backwards on the hub until it hits something. If a spinning cast iron damper ring hits something stationary it will explode. For that reason alone the crank damper should be replaced if it is more than 20 years old. Purchase a replacement that is 100% steel (steel hub and steel ring), heavy (i.e. thick), and fully bonded; the 351 Boss damper was also heavy (thick) and fully bonded. Three excellent, readily available choices include:
(1) Romac #0203
(2) BHJ Dynamics #FO-EB351C-7
(3) ATI #918900

Removing The Timing Cover & Dropping The Oil Pan

The cam sprocket of the OEM camshaft timing set has plastic teeth, and those teeth get brittle with age. If those teeth should strip-off the cam gear while the engine is running bent valve stems and/or bent push-rods shall be the result. I am in full agreement with Chuck and Garth in regards to replacement of the OEM timing set with a timing set in which both gears are made of 100% steel.

To replace the timing set requires removal of the coolant pump, the timing cover, and the fuel pump. Anyone who has done this job will tell you its much easier to remove and reinstall the timing cover if you drop the oil pan too. While the pan is off there are several other issues you can address.

If the engine is equipped with the original coolant pump, its only a matter of time before the rubber seal will begin to leak, since you're removing the pump this may be a good time to consider replacing it. Some aftermarket coolant pumps have the coolant recirculation passage "plugged" as they come out of the box. If this is the case, drill the passage open. The Flow Kooler pump, which is advertised to increase coolant flow at low rpm, is a popular choice for Pantera owners.

If the engine is equipped with the OEM fuel pump, its only a matter of time before its rubber diaphragm cracks and begins to leak gasoline. If the gasoline leaks inwardly it will dilute the motor oil, and can lead to an expensive engine repair. Since you have to remove the fuel pump this may be a good time to consider replacing it.

The OEM 1972-1974 Cobra Jet camshaft and the aftermarket replacements are indexed 4° retarded from the camshaft’s originally intended 1970-1971 timing. Ford retarded the timing back in 1972 in order to reduce dynamic compression; this is not needed today however. For a nice improvement in thermal efficiency Cobra Jet camshafts should be timed straight-up; this means the timing of the Cobra Jet camshafts should require advancement by nominally 4°. If the camshaft's LSA is 117° (OEM camshaft) time it for 117° ICL; if the camshaft's LSA is 115° (replacement versions) time it for 115° ICL. That timing doesn't apply to any other camshaft however, just the Cobra Jet cam. A 9-keyway (multi-index) camshaft timing set makes this easy to accomplish. So when you replace the OEM camshaft timing set spend the extra money and purchase one with the 9-keyway crankshaft sprocket.

Now is a good time to replace both crankshaft seals. A replacement for the rubber OEM front seal shall be included with the timing cover gasket set. The OEM rear crankshaft seal is made of rope, and an upgrade to a neoprene rubber version is highly recommended (Fel-Pro #BS40042). The rear seal can be replaced without removing the crankshaft from the block. Be sure to remove the small sharp pointed pin in the seal groove of the #5 main bearing cap when installing a split-rubber rear crankshaft seal.

The oil pan sump should be cleaned while it is removed. Don't be surprised if you find ribbons of babbit lying in the sump. This is one possible complication arising from the first of the engine's three weaknesses, i.e. the big "ports" in the sides of the tappet bores. I consider the improvement to the lubrication system's performance realized by the installation of tappet bore bushings well worth the $400 USD the installation kit costs. Unfortunately to install them requires the complete disassembly of the engine. Admittedly there are many 351C engines in operation without them, operating just fine in spite of the eventual bearing wear that occurs. I won't tell you the tappet bore bushings are "must haves" ... but if you find ribbons of babbit lying in the sump you may begin to feel differently about the necessity of tappet bore bushings.

Replacement of the OEM rod nuts with ARP #300-8371 nuts is a beneficial precautionary measure to alleviate the possibility of connecting rod failure. The connecting rods fail from time to time because the threads strip out of the connecting rod nuts. When the big-end cap of a connecting rod loosens while the engine is running it mangles the connecting rod, inflicts damage to the crankshaft's rod journal and to the cylinder wall. Valve train parts are also bent and mangled. It can be quite costly to repair, if not entirely ruining the short block. This is the second of the engine's three weaknesses. Installing the ARP nuts does not require complete disassembly of the engine; installing them can be accomplished by simply dropping the oil pan.

The engine should have been equipped with an oil pan with a built-in windage tray, and the good high volume oil pump inlet tube, from the factory. Those are the same parts as installed in the 351 Boss version of the engine. The only way to improve the oil pan would be to install a 9 quart racing oil pan having baffles and hinged doors. However, the racing pan is not a "must have" if the car is only driven conservatively. Now would be the time to replace the oil pan however if you were considering doing so.

Removing The Intake Manifold & Heads

This brings me to another problem mentioned by Chuck and Garth. The heads of the OEM valves crack off their stems every once in a while because the valves are brittle. When a valve head falls off while an engine is running it usually cracks the cylinder wall, punches a hole in combustion chamber, beats up the piston dome, and bends the connecting rod. It can destroy an engine, which is why people recommend valve replacement so adamantly. This is the third of the engine's three weaknesses. The OEM valves are also designed for multi-groove locks which are frowned upon for performance applications. The precautionary measure to take for both issues is to replace the OEM valves with valves which are “non-Ford" and "non-brittle" and which have single groove valve stems, i.e. valves designed for single groove style split-locks, such as the 351 Boss valves. The single groove split-locks are not designed to allow valve rotation; they grasp the valve stems tightly and are considered a better choice for high performance or high rpm. Unfortunately, valve replacement involves removal of the intake manifold and heads. I am sure this is a "bigger job" than you were contemplating. If you decide to replace the valves you'll need new single groove style "split-locks" to complement those single groove valve stems. I'd advise you to use "steel" valves similar in material to the OEM valves unless you plan to install bronze valve guides, cast iron is not considered a good valve guide material for stainless valves ... although its considered OK for the valve seats.

Now is also the time to replace the valve stem seals ... more brittle rubber parts.

Since you're replacing valves, now would be an ideal time to replace the open combustion chamber head castings (D1ZE) with quench combustion chamber head castings (D0AE or D1AE, preferably D0AE), thus raising the engine's nominal compression ratio from about 8.7:1 to either 9.6:1 or 10:1, depending upon which castings you install. This is compatible with 95 octane petrol (equivalent to 91/92 octane in the US & Canada). I am not making this suggestion for the increase in horsepower, but for the improvement in "snap" it gives the engine. Obviously not a "must have", but the improvement in the engine's performance (thermal efficiency) is well worth the money, it is the single best improvement you can make to the engine, and as I said, it is an ideal time to do it while the heads are off for valve replacement.

You can visually inspect the camshaft lobes & tappets for wear while the intake manifold is removed. Be sure to return each tappet to the same "bore" it came out of. Replacements for the Cobra Jet cam are available from several suppliers:
Blue Racer #972227
Melling #SYB-29
Clevite #229-1883
Sealed Power #CS-650
Manley #MS700
Lunati #11104LUN
Crane #C580

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