Big-Block Ford Engine Inspection and Parts Cleaning Guide

At this point, you should have what would appear to the uninitiated as a large number of random, very dirty auto parts. The various components of your engine rebuild project now need a thorough inspection and cleaning to reveal any damage and to determine which parts will need to be replaced and which may be returned to within manufacturer specification through machining.

During the disassembly phase, the engine has been separated into four major components:

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• Intake manifold and cylinder heads
• Valvetrain, consisting of camshaft, lifters, pushrods, and rocker arms
• Rotating assembly, consisting of the crankshaft, connecting rods, pistons, damper, and flywheel
• Cylinder block

And while the average back-yard mechanic is fully capable of visually inspecting and cleaning the rocker arms, pushrods, and camshaft, I would suggest you place the other  engine components into the hands of professionals who are better equipped for the task.

 

The crankshaft, rods and pistons, and cylinder heads have finally arrived at the machine shop, where they will be carefully examined, measured, and cleaned prior to machining.

The bare cylinder block sits in the bed of my pickup awaiting the muchneeded attention it will receive at Jordan Automotive Machine. At this point, we have removed all the core and freeze plugs to prepare the block for cleaning and machine work. While we’ve noted no obvious damage or defects in the block, only a thorough cleaning and checking with specialized tools will tell the entire tale.

 

I personally take exception to the theory that you can achieve the same results with a rented power washer or steam cleaner as a machine shop that is equipped with a baking oven and hot chemical bath. Media blasting is an effective means of cleaning engine components other than the cylinderblock. A session in the blasting cabinet  will usually remove almost all traces of rust, corrosion, and paint from your parts. However, the media used to blast the parts consists of aluminum oxide or glass beads propelled by high-pressure air, so parts that have been media blasted will require additional cleaning with a liquid solvent such as Acetone to remove any leftover media residue that may have collected in out-of-the-way places.

 

Step-1: Visual Inspection

Master Machinist Gil Jordan conducts a preliminary visual examination of a bearing insert, connecting rod, and piston assembly and determines that the pistons will need to be replaced as a result of wear indicated by scuffing of the skirts. We’ll select a modern aftermarket piston of superior design to replace the OE parts.

 

Step-2: Note Any Wear (Critical Inspection)

While examination of the connecting rod bearings from the 429-ci shows the wear of nearly 100,000 miles of service, no obvious problems are detected during the visual inspection. The “reading” of bearing inserts for wear patterns or gouging may reveal potential problem areas that will need to be addressed. When reading bearings, one should be aware that the top connecting rod inserts (those seated in the rod) will show wear first, while the main bearing inserts in the cap are the first to show wear. This is due to the loads placed on the bearing while the engine is running.

 

Step-3: Note Casting Number

The D0VE-A casting on our cylinder block shows that it is indeed a 429 Cobra Jet part and correct for the car it was removed from. Casting numbers and date codes are important when authenticating collector cars, but also assist the machinist in determining the proper dimensions and ordering the correct replacement parts for   your engine.

 

The casting date on this block is located in the lifter gallery and indicates that it came out of the oven at the Dearborn Iron Foundry (DIF) on May 19, 1969.

 

 

 

Step-4: Check VIN

The car’s VIN stamped on this machined surface at the back of the 429-ci block leaves no doubt that the car still has its original engine in place. In the collector car hobby, this is referred to as a “numbers matching car” and has greater value than a similar car that does not have correctly date coded cast or stamped parts.

 

Even Cobra Jet blocks that are not drilled for 4-bolt main caps are cast and machined so that they may be installed. Later 2-bolt-only blocks have a large shoulder cast where the extra main cap bolt would be.

 

Step-5: Inspect Valves

Visual examination of the valves removed from the 429’s cylinder heads reveal no evidence of burning. However, the exhaust valves were obviously loose in their guides and the stems show signs of galling, which will dictate valve replacement. Both the intake and exhaust valveguides will be replaced during cylinder head reconditioning as a matter of course.

 

Step-6: Inspect Oil Pump Pickup

The oil pump pickup and screen show little sign of sludge or debris,  indicating that this engine received oil changes at regular intervals during its lifetime. It is recommended that the oil pump be replaced during any engine rebuild and in this case, we’ll opt for a high-volume replacement pump as an overall aid to lubrication.

 

Step-7: Inspect Oil Pan

Close examination of the oil pan reveals surprisingly little sludge buildup. You can the factory baffling and the holes drilled into the sides of the pan to allow oil to flow into the unique “wings” welded onto the pan as part of the 1970 Torino pace car modification. This modification to the oil pan increased its capacity and  prevented the engine from being starved for oil when the car was driven on racetracks with highbanked turns.

 

Step-8: Check Cylinder Bores (Critical Inspection)

Gil Jordan uses a dial bore gauge to check the cylinder bores of the block. Measurements are taken parallel to the crankshaft at the top and bottom of the bore to determine if the bore is concentric and not out of round due to wear. These measurements are then repeated at the same heights in each bore, perpendicular to the crankshaft. Each cylinder bore is also measured to determine taper from top to bottom. If the out-of-round and taper limits listed by the manufacturer are exceeded, the cylinders will need to be bored oversize to return them to specification.

 

Step-9: Check Journals (Critical Inspection)

Following a visual inspection, the crankshaft’s main and rod bearing journals are checked with a micrometer to determine wear and if they have previously been machined. In this case, the crankshaft checks standard but shows enough signs of wear to warrant cutting .010 off the journals to bring it back to within factory specification.

 

 

Step-10: Prepare for Cleaning (Important!)

The cabinet on the on the left is a Peterson hot tank. The one on the right is a Bayco oven. Parts placed in the oven are slowly heated to 700 degrees F and then slowly cooled. This process turns sludge into ash and makes it easier to remove. All core plugs must first be removed from a cylinder block before it goes into the oven. Otherwise, ash may collect behind the plugs and eventually find its way into the oil and destroy your newly rebuilt engine.

 

Step-11: Prepare for Cleaning

The Peterson hot tank/jet sprayer exposes the parts to a sodium hydroxide solution heated to 180 degrees F. This removes dirt and grime from engine parts more effectively than cleaning in a home shop environment. Our cylinder block, heads, and crankshaft will be treated to a thorough cleaning before the next step in the rebuild process.

 

 

 

 

 

Step-12: Parts in Sprayer

The disassembled 429-ci cylinder heads are secured to the vertical rack in the jet sprayer and made ready for the first step in their path to reconditioning. Once cleaned, the heads will be checked for defects then further cleaned prior to machining. The 429’s crankshaft joins an assortment of other engine parts in the jet sprayer. A good hot bath in sodium hydroxide will ensure that all the oil passages in the crank are free of built up sludge and debris.

 

Step-13: Cylinder Block Done in Sprayer

The cylinder block has finished its turn in the jet sprayer and will now be cleaned and checked prior to being machined.

 

 

 

 

 

 

 

 

 

Step-14: Watch Out for Surface Rust

All oils are removed from the cylinder block during chemical cleaning, and it will begin to show surface rust very quickly. The remaining factory applied color on the exterior of the block is a testament to the quality of paint used by Ford in 1970.

 

 

 

 

 

 

 

 

Step-15: Magnaflux Check

The block undergoes a Magnaflux check to detect hidden cracks or defects it. This process consists of securing a strong electromagnet to the part and spraying a metallic dust onto the areas to be checked. The area around the main bearing caps and webbing is critical and susceptible to cracking, thus it is checked carefully.

 

 

 

 

 

 

 

 

 

 

 

Step-16: Check Lifter Galleries

The lifter gallery is also susceptible to cracking. Areas of the block that have sharp edges are checked very carefully since cracks often appear where castings are narrow, thin, or in areas of stress.

 

 

 

 

 

Step-17: Note Any Cracks

A crack exposed by the Magnaflux process appears as a yellow line (middle right of this photo). The bad news is this block has a crack in the lifter gallery and may not be able to be saved. The good news is this is a Pontiac block, and not our 429-ci, which checked out fine at this stage.

 

 

Step-18: Check for Gasket Residue

Even after all the heat and chemical cleaning, there are still remnants of the original head gaskets stuck to the surface of the block. It is obvious that additional attention will be needed to clean these surfaces completely.

 

 

 

 

 

Step-19: Remove Gasket Residue

Light tapping with a brass mallet will help loosen the baked-on head gasket material without damaging the deck surfaces of the block. One way or another, getting this block clean enough for the next step will be labor intensive.

 

 

Step-20: Remove Gasket Residue

After softening things up with the brass mallet, we used a carbide tipped scraper to remove the larger pieces of gasket material. The deck surfaces are finally starting to show signs of progress.

 

 

 

 

Step-21: Remove Remaining Gasket Residue

A pneumatic tool mounting a soft wire brush is used to remove any remaining head gasket material from the deck, leaving it clean and unmarred.

 

 

 

 

 

 

Step-22: Determine Machining Steps (Important!)

With the deck surface cleaned, we’re ready to continue the checking process to determine what machining steps will be necessary. Note: The 385 series Ford engines have three different deck heights. Your deck height should be checked and noted prior machining. The 1968 to 1970 deck height is 10.300 inches, 19701⁄2–1971 blocks have a 10.310-inch deck, and 1972-up deck height is 10.322 inches.

 

Step-23: Check Line Bore (Critical Measurement)

To check the line bore, you must first replace the main bearing caps and tighten them to factory torque specifications. Prior to replacing the caps, run a fine tooth flat file over the mating surfaces of the caps and their registers in the block to remove any small burrs that might interfere with fit.  After filing, clean the caps and registers with solvent to remove any foreign material.

 

 

 

 

 

 

 

 

 

 

Step-24: Lubricate Main Cap Bolts

After being thoroughly cleaned, the threads and the area under the heads of the main cap bolts received a light coat of motor oil. This is to ensure accurate torque readings.

 

 

 

Step-25: Seat Bearing Caps

Put the main bearing caps into place in their registers, using a soft mallet to seat them, and then torque to factory specification.

 

 

 

Step-26: Check Dial Bore Gauge

The dial bore gauge is set and doublechecked prior to checking the align bore.

 

 

 

 

 

 

 

 

Step-27: Measure Bearing Bores (Critical Measurement)

The dial bore gauge is inserted into each main bearing bore and measurements are taken in the same fashion as those taken in cylinders. Sizes and any deviations are recorded. 385-series engines are not known for align bore problems, but should a problem exist, it can normally be corrected through honing.

 

 

 

 

 

 

 

 

Step-28: Surface Rust

Once they have been chemically cleaned the cast-iron cylinder heads begin to surface rust just like the block. They heads will have to be rusty just a little while longer as the next step in their resurrection is performed.

 

 

 

 

Step-29: Magnaflux Check

Both cylinder heads receive a Magnaflux check before we precede any further. Areas of particular cracking concern include the area around the valvesprings and the spaces adjacent to the exhaust valve seats in the combustion chambers. If a cylinder head shows a small crack, it isn’t the end of the world. In many instances, welding can repair them.

 

Step-30: Media Blasting

Once chemically cleaned, an assortment of parts—from the cylinders heads and intake manifold to brackets and fasteners—all have a date with the blasting cabinet. In this step we use an abrasive under air pressure to remove paint, scale, and other foreign material, leaving the part stripped back to bare metal. If parts are not going to receive primer or paint soon, they should be coated with WD-40 to prevent rust from setting in again.

 

This freshly cleaned 429-ci cylinder head (left) is shown next to a cylinder head from a Ford small-block V-8. Note the huge round intake ports that are a trademark of the 385 series engines.

 

 

 

Step-31: Inspect Cylinder Heads

A close-up of the intake port of a 429 Cobra Jet cylinder head shows a little more casting flash that needs cleaning up for maximum flow.

 

 

 

 

With back lighting you can see that even the mighty 429 Cobra Jet cylinder head suffers from the inefficient exhaust port design that limits performance. This weakness evolved as a result of Ford engineers being tasked to configure the engine to fit between the shock towers of midsize passenger vehicles. Efficiency and power were compromised for fit. In the case of the 351-ci  Cleveland 4-V and 429 CJ heads, the huge intake ports actually create more of an imbalance when combined with their anemic exhaust side.

 

Step-32: Prepare for Re-Facing

Chemically cleaned, Magnaflux checked, and bead blasted the cylinder heads now await the machining processes required for installing new valveguides and re-facing the seats to make them as good as new.

 

 

 

The 429 Cobra Jet’s closed combustion chambers house huge valves for maximum performance. Of particular note is the fact that the intake valve seats are cut at a 30- degree angle, which allows the valve to seal better but restricts flow slightly at higher cam lift. The exhaust valve seats are cut at the more conventional 45 degrees, obviously in an attempt to offset the poor exhaust-port flow characteristics.

 

Step-33: Clean Intake Manifold

The intake manifold has been through the hot tank and the blasting cabinet and will soon be ready for primer and paint. All threaded holes will be chased with a tap prior to replacing any external fittings such as the temperature sender and choke stove.

 

 

On some engines, the intake manifold cover is held in place by common bolts, but on 385 series engines, it is affixed by rivets, which must be carefully removed and replaced. Should you not be able to replace the rivets, the hole in the intake may be threaded and a bolt installed.

 

Step-34: Clean Manifold Cover

Before cleaning the intake manifold, remember to remove the stamped steel cover attached to the bottom. Not only can dirt and sludge accumulate this area, it can collect abrasives from the blasting cabinet as well.

 

 

The cover for the bottom of the intake manifold has been cleaned separately in the bead blaster and is now ready to be reinstalled.

 

 

 

 

Step-35: Clean Oil Pan

The specially modified oil pan for this particular 429-ci has been hot tanked, media blasted, and then hot tanked again to remove any particulate matter. It now awaits primer and final engine color.

 

 

 

 

 

I use a two-pronged approach to inspect components to determine if they remain within factory specification and to detect any flaws. While a set of micrometers, dial indicator, and a dial bore gauge are within most home shop budgets, it might be hard to justify the expense of the equipment needed to Magnaflux parts for hidden cracks and other specialized tools found in a professional automotive machine shop. Both methods of inspection are necessary.

 

Written by Charles R. Morris and Republished with Permission of CarTech Inc