In Chapter 1, we told you about our subject engine, a 1965 289-2V engine removed from Jeff Fischbach’s Mustang convertible. When Mustang Monthly decided to target this engine for a “Budget 289 Build-Up,” they invited us to follow to gather information for this book. The engine had failed coming off of a Los Angeles freeway. Suddenly, it had no power and developed a horrible knock in rhythm with the crankshaft. When Mustang Monthly Senior Editor Jim Smart was troubleshooting the noise, he knew it was serious. He started by shorting each of the spark plugs out one at a time. When he pulled the number-4 spark plug wire, the knock stopped – a bad sign. He also did a compression check. All cylinders checked healthy except for number 4 which came in low. Pouring some oil into number-4 cylinder and checking compression showed a big improvement – another bad sign. Cylinder sealing on number-4 was poor for a reason. The piston was cracked, which allowed compression to escape. That cracking also caused the knock.
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Jim also learned in the course of the teardown that number-5 cylinder on the opposite bank was in all kinds of trouble, too, even though compression checked within limits. Coolant was leaking into cylinder number-5 from a defective head gasket while the engine sat. Compression from the number-5 cylinder undoubtedly leaked into the water jacket, aggravating overheating issues already caused by the right-bank cylinder- head gasket being installed backwards during the last rebuild.
What we learned from this teardown is something we hope you’ll learn from this book – what not to do when you rebuild your small-block Ford. Because our 289 engine experienced a really sloppy mass-production-style rebuild at some time in its past, it was not properly machined and assembled, which led to the failure. We’re going to talk about this failure in great detail to help you avoid the same mistakes. We’re also going to address common mistakes that cause a lot of engine failures.
Jeff’s 289 engine failed for two fundamental reasons – the water pump wasn’t installed properly (no backing plate), and the right-bank cylinder-head gasket was installed backwards. The backward cylinder-head gasket is an easy mistake to make because it isn’t very apparent at first glance. It happens whenever we’re not paying attention to what we’re doing during an engine build. Each and every head gasket has “FRONT” stamped in the surface to ensure proper installation, but people mix it up all the time building Ford V-8s. Cooling passages in the cylinder- head gasket must always go at the rear of the block to ensure proper cooling. This allows coolant to circulate completely through the block and heads on its way to the thermostat and radiator.
Whenever we install both head gaskets backwards, trouble begins the minute we fire a new engine. If we get both head gaskets backwards, overheating will become apparent immediately. Whenever you install a small-block Ford cylinder-head gasket backwards, coolant flow is cut off to the rear of the block and cylinder heads. Coolant then circulates only at the front of the block and heads, causing a large percentage of the engine to overheat. In this case, only the right bank ran hot because a significant percentage of the coolant was allowed to circulate and cool normally.
In time, engine oil broke down on the extremely hot surfaces – cylinder walls, pistons and rings, bearings, valveguides, and more. Because cylinder number 4 suffered the greatest amount of thermal abuse, it failed first. Extreme heat cracked the piston from the crown to the skirt. It probably wasn’t noticeable until the piston cracked all the way through, when a horrible misfire and knock developed.
Jeff’s engine failure wasn’t something that happened overnight. It happened over a period of many years. Heat went to work on the rear of the right bank of cylinders, resulting in eventual failure. Had he continued to drive the car the way it was, the engine would have seized due to total number-4 piston failure. Had that not done him in, cylinder number 5 on the left bank would have finished the engine off by drawing coolant into the cylinder bore.
Step by Step: Tearing Down the Engine
Step-1: Remove and Inspect the Flywheel
Jim Grubbs Motorsports is going to rebuild our 289 engine. Disassembly is organized, with all parts being cataloged and properly stored. Knowing which parts came from where helps us to determine why this engine failed. First, we remove the flywheel, which needs resurfacing. The flywheel suffers from heat cracking because the clutch disc was improperly installed.
Step-2: Remove the Separator Plate
The separator plate slides off the alignment dowels on the back of the block.
Step-3: Put the Engine on an Engine Stand (Special Tool)
Once the separator plate and flywheel are removed, the engine is fitted to an engine stand for the teardown. You can buy an affordable engine stand from Harbor Freight for around $75. We suggest one with four casters for the best stability. Notice the rebuilder’s overheated detector at the freeze plug on the righthand cylinder head. It indicates an overheat (the dot) – actually the rebuilder’s fault in this case.
Step-4: Remove the Water Pump
Engine failure happens for all kinds of reasons. Here’s one. When the water pump was replaced, someone forgot to use the steel cover that goes on the back of the water pump. That’s why the impeller ground this circle into the timing cover. Not only is impeller contact with the timing cover unacceptable, but coolant flow was also hindered by the absence of the plate. This is one reason why this engine ran so hot.
Step-5: Remove the Valve Covers
Both valve covers are removed. This engine, for all the heat damage we found, was surprisingly clean inside.
Step-6: Remove the Intake Manifold
The intake manifold bolts are removed next. Place these bolts in a plastic container and label it so you can find the bolts when you need them. Remove the intake manifold.
Step-7: Remove the Rocking Arms
Next, remove all rocker arms as shown. Keep them lined up with the cylinders they came off of. This enables you to examine wear patterns. Here’s one result of sloppy massproduction rebuilding – incorrect valves. On one bank, we have the correct valvestem length, short and flush with the top of the retainer. On the other bank, we have longer valvestems, designed for mid-1966 to ’77 small-blocks with rail-style rocker arms. Note the longer valvestem tip, designed for the rail-style rocker arm. This throws the rocker-arm geometry off with 1962 to early 1966-style rocker arms.
Step-8: Remove the Cylinder Heads
Remove all of the cylinder head bolts and put them in a labeled plastic container. Take your time. You need an organized teardown, with all fasteners properly cataloged for proper assembly later on. Cylinder heads are pried from the block. Hold onto the cylinder heads when you are prying them loose. They can slide off the block dowels and land on your feet. Take extra care when you are removing the heads, and keep track of which bank each head came from.
Step-9: Inspect the Head Gaskets
This 289 sat for a year after it failed. Look what coolant leaking into cylinder number 5 from a defective head gasket did. Electrolysis between the aluminum piston and iron cylinder, via the coolant, caused the piston to corrode badly. Coolant came from this water jacket into the bore.
Step-10: Measure the Bores (Precision Measurement)
Measuring the cylinder bore with a micrometer (called “miking” the bore) brings bad news. Jeff’s block has already been bored .040-inch oversize. We could bore it to .060- inch oversize, but this would be a risky practice. We need a replacement block.
Step-11: Inspect the Bores
Our 289 engine didn’t live very long after its previous rebuild. There are no ridges at the tops of the cylinder bores, which happens as piston rings wear into the cylinder walls short of the top of the cylinder. These are cheap cast .040-inch oversize pistons.
Step-12: Disassemble the Intake for Cleaning
The C5AE four-barrel intake manifold is disassembled for cleaning. The manifold heat stove cover is removed as shown. Then, the manifold goes into a cleaning machine, which tumbles the iron with steel shot for a “like-new” appearance.
Step-13: Clean the Intake
This is the cleaning machine composed of a rolling carrier that exposes the iron pieces to steel shot, which is blasted against the iron. When these parts come out, they will look like brand new iron.
Step-14: Inspect the Harmonic Balancer (Important!)
The harmonic balancer is 40 years old and needs to be replaced because the rubber has deteriorated. We will toss this one and replace it with a new one.
Step-15: Remove the Harmonic Balancer
The harmonic balancer is removed next using a puller. Remove the large crankshaft bolt first. Then, screw the bolt back in a couple of threads for the puller to work against.
Step-16: Removing Timing Cover and Set
Remove the timing cover and timing set. Examine the chain for stretching. Excessive stretch tells us something about wear patterns in the chain, gears, and block.
Step-17: Removing the Oil Pump
After you have removed the oil pan, remove the oil pump and shaft. We suggest replacing the shaft and pump. An oil pan with a stripped-out drain plug should be replaced.
Step-18: Remove the Rods and Pistons
Piston and connecting rod removal is next. Remove the rod bolt nuts and gently tap the rod bolts as shown with a hammer, pushing the piston and rod out through the top of the block. As with the rocker arms mentioned earlier, keep the pistons and rods with the cylinders they came out of for wear inspection purposes.
Step-19: Inspect the Rod Bearings
Close inspection of this rod bearing reveals some bad news. Look at the damage to this rod bearing from excessive engine heat and oil breakdown. With oil breakdown came excessive friction, grinding the bearing down to the copper.
Step-20: Remove and Inspect the Main Caps
The main bearing caps are removed next. Like the rod bearings, close inspection of the main bearings tells a story about poor engine assembly technique. Look at this badly scored main bearing. A piece of dirt got in there during assembly. When the engine was started, the grain of dirt was ground into the bearing. A close study of the main bearing journals shows excessive heat damage. Oil breakdown here caused excessive scoring.
Step-21: Remove the Crankshaft
The crankshaft is removed next. Remember what your mother (and OSHA) always told you: Lift with your legs – not your back – to prevent back injury.
Step-22: Inspect the Crankshaft
The crankshaft journals are measured with a micrometer. These journals have already been machined down .020 inch and are badly scored. We could machine this crankshaft to .030-inch undersize. Instead, we’re going to find another “1M” crankshaft.
Step-23: Inspect the Main Bearing
Remove all of the main bearings, inspect the wear patterns, and throw them away. We inspect wear patterns because we want to know the history of the crankshaft. If the crank is distorted or bent, main bearings will be excessively worn toward the sides and radiuses.
Step-24: Remove the Rear Main Seal
The rear main seal is removed and tossed. Wear issues are important here, too. Inspect the number-5 main journal and seal lip while you’re here. This, of course, does not apply to late-model 5.0L engines with one-piece rear main seals. It does, however, apply inspection-wise. Always check the seal contact areas. Scored seal contact surfaces mean oil leakage later on.
Step-25: Remove the Camshaft and Lifters
To remove the camshaft, you need to remove all of the lifters first. As you remove the lifters from their bores, inspect the cam contact surfaces for wear patterns. Once the lifters are removed, remove the front cam retainer plate by removing the two bolts. Then, gently slip the cam out of the block.
Step-26: Inspect the Lifters
Excessive and abnormal lifter wear tells us this engine suffered from oil breakdown, which happens with overheating.
Step-27: Remove Freeze Plugs (Important!)
Remove all of the freeze plugs and oil galley plugs. This enables the machine shop to clean out the water jackets and oil galleys. The block needs to be completely bare.
Step-28: Remove the Cam Bearings
Cam bearings are removed next using a cam bearing installation tool. Bearings are removed from the front of the block, working toward the back. We knock them out the same way we install them. These cam bearings were badly damaged during installation. Oil breakdown from extreme heat also did a lot of damage.
Step-29: Remove the Oil Galley Plug
There is an oil galley plug at the top of the block, located beneath the intake manifold. Remove this plug, which makes way for a more thorough block cleaning.
Step-30: Remove the Cam Plug (Important!)
The screw-in oil galley plugs at the rear of the block must be removed. Don’t forget to remove the cam plug.
Step-31: Remove the Oil Filter Adapter
Remove the screw-in oil filter adaptor.
Step-32: Inspect the Chambers
Inspection of the right cylinder head shows evidence of a troubled number- 4 cylinder (bottom chamber). Notice how dark the chamber is from a lack of compression and oil burning. The rest are normal, with white exhaust valves and tan chambers.
Step-33: Remove the Valves
Cylinder head disassembly begins one valve at a time. Each spring is compressed and the two keepers are removed. Sometimes, valvespring retainers and keepers become seized. It’s a good idea to whack on the side of the retainer with a hammer, and then compress the spring again when the keepers stick. All eight valves from each head need to be lined up for inspection to determine wear patterns that need your attention.
Step-34: Inspect the Valves
Each valve is inspected closely. This cylinder head has obviously been apart before and had a valve job. The valve faces show abnormal wear to the point that they were sinking deeply into the seats.
Step-35: Inspect the Valve Seats
When we look at the valve seats, the valve face’s condition makes sense. A bad valve job (improper seat and valve face angle) has caused the valves to wear deeply into the seats. All 16 valves and seats will have to be replaced.
Step-36: Inspect the Valve guides
Our cylinder heads send a mixed message. Some valveguides are bronze – some are not. We are replacing all 16 guides for uniformity.
Let’s take this idea a step further. Had the car sat for several months, coolant would have filled cylinder number 5, causing a nasty hydro-lock the first time Jeff tried to start the engine. Hydrolock is what happens when we try compressing fluid in the area above the piston. Because fluid cannot be compressed, more fragile elements (piston, rod, and block) are compromised instead. Typically, the piston and rod both fail – even causing the cylinder wall to crumble in the process. We have seen hydro-locked engines in which the cylinder wall failed right along with the piston and rod, causing coolant to flood the oil pan. In this case the hydro-lock would have bent or snapped the number-5 connecting rod, and even could have broken the crankshaft.
Jeff probably noticed his Mustang’s temperature gauge running on the high side, especially during hot weather, but it was never quite hot enough to boil over. As Jeff, and earlier his uncle, drove the Mustang, the right bank of cylinders ran very hot without notice. Adding insult to injury was the fact that the water pump was installed without a backing plate, which further aggravated cooling issues. Without the steel backing plate, coolant was never properly channeled through the pump and the water jackets, making a hot-spot situation even worse. In this case, the water pump impeller contacted the timing cover due to the missing plate. Why anyone removed this plate in the first place is beyond us. In any case, it all contributed to engine failure.
Written by George Reid and Republished with Permission of CarTech Inc
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