The End Is Near! 10 Warning Signs Your Engine Is Near Death

This is just a sampling of our broken parts we’ve collected over the years. The broken blocks, torched heads, and melted pistons were too numerous and heavy to save. There are lessons to be learned from all of these broken parts.

This is just a sampling of our broken parts we’ve collected over the years. The broken blocks, torched heads, and melted pistons were too numerous and heavy to save. There are lessons to be learned from all of these broken parts.

Words And Photos: Jeff Smith

Break out the defibrillator and practice the internal combustion engine version of CPR (which stands for Cardio Piston Resuscitation). We’re about to embark on a journey that might save your engine’s life. The term Near Death Experience (NDE) is well documented in the human side of things. You’ve probably heard the stories: in near death a bright light emits from the dark tunnel of death and in an instant your entire life flashes before your eyes. We don’t know anything about those psychological traumas, but we’ve been through more than a few END experiences. Those are Engine Near Death experiences.

We should warn you – this is not a feel-good story. Nothing warm and fuzzy will be discussed here. All these points are signs your engine is in serious distress. But if you catch these warning signs early enough, you might just avoid the termination of internal combustion activity. If nothing else – caught soon enough after an END experience, you might be able to save a few parts and maybe a few coins along the way, too.

We’ve compiled a short list of 10 warning signs of END traumas in no particular order. All you have to do is recognize the signs and know what they mean. Once you do that, the engine life you save – just might be your own! Or at least you can recognize the symptoms and shut your engine down before it turns all those expensive parts to a steaming pile of junk!

1. Lash Changes

This might seem like a small thig, but it can be a subtle alarm. Mechanical lifter engines use lash or clearance between the rocker arm and the valve and despite a common misconception, if everything is working properly, warm engine lash clearance does not change. If the lash changes – something is moving. This is true for both flat and roller lifter camshafts.

Generally, if the lash increases, this means something is wearing which has increased the clearance in the valvetrain. This can be a flat tappet lifter that is in the process of flattening a cam lobe or it could mean a bent pushrod or perhaps a fractured rocker arm. With roller lifters, a minor increase of 0.003 to 0.005-inch of lash could be a warning sign that the lifter’s roller bearings are failing. This is just about the only signal you’ll get that something is wrong before the bearings begin to disintegrate. When that happens, their exit is quickly followed by catastrophic engine damage as those little needle bearings use engine oil to transport them throughout the engine. If you’ve never experienced this – consider yourself lucky. Those tiny little roller bearings end up between the pistons and cylinder walls – which can cause serious cylinder wall scoring. Or, they can find their way into the oil pump and cause it to seize, which is never a good thing.

2. Shiny Stuff in the Oil

Here’s the scenario. You’re at the drag strip and the engine is running great. You make a pass with a trap speed of 115 mph. You make a minor jet change and the car slows down 2 mph. You go back to the original jet and the car slows down another 3 mph. Now the car is slower by 5 mph. This is when you start looking for the cause. We like to start by pulling the valve covers.

That’s when you will see it. In the oil that’s still trapped on top of the cylinder head, there’s shiny stuff floating in the oil – like little silver and copper flakes. When you see this, the damage – unfortunately – has already occurred. What you are looking at is either connecting rod or main bearing material that has been stripped off the bearings and is floating in the oil. The only intelligent solution is to put the car on the trailer, take it home, and yank the engine.

This has happened to us on the dyno on a couple of occasions. In the most recent example, we put a centrifugal supercharger on a 502 big-block Chevy crate engine. After making 800-plus horsepower, the engine quickly lost power and we pulled the valve covers to discover shiny aluminum flakes in the oil. We discovered the Number 2 main bearing had begun to pull bearing material and had scratched the main journal. This occurred because the stock production big-block aluminum main bearings couldn’t handle the extra load of the added 300-plus horsepower and torque. This was a stock crate engine bottom end and the lesson there was that we should have replaced the stock aluminum bearings with softer tri-metal performance bearings before pushing this engine that hard. But we caught the problem before it did more serious damage.

3. If the Engine Squeaks – Shut it Down

This might sound weird but it happens more often than you might think. There are several reasons for this and none of them are good. The above-mentioned mechanical roller lifter failure can cause an engine to squeak. A friend with a radical, 650 hp 434c.i. small-block Chevy street car called me one day and asked “My engine started squeaking last night on the way home – what do you think it is?” It turned out he had lost the bearings in a mechanical roller lifter and they went all through his engine. The squeaking was the roller follower banging against its axle.

I’ve also heard engines squeak when suffering from disintegrating main bearings. In this case, it was a newly-rebuilt 406c.i. small-block where the balance shop neglected to put the dowel pin in the crank and balanced the assembly with the offset weight in the wrong position. When we assembled the engine, we placed the flexplate in the proper orientation and the engine seemed to vibrate slightly. When the car didn’t run well at the track, the engine began squeaking just as we returned home. The last few miles put so much heat in the mains that the block’s main webbing turned blue, which destroyed the block. If you hear a loud squeak – consider yourself warned. Or you can do what Westech’s Steve Bule’ says and “perform the sign of the cross over your heart and sprinkle that motor with holy water ‘cause it’s dead.”

4. Sudden Oil Pressure Drop

This is enough to give anybody a heart attack, but for once, this might not be a fatal flaw. In cases where the oil pressure does not drop to zero but instead falls 10 to 20 psi at higher engine speeds, there is a possible fix. The logical assumption is that this is caused by low oil level that allows the pump to suck air. This is a common problem with high rpm LS engines with stock oil pans because the oil pump spins at engine speed compared to previous designs where the pump spins at camshaft or half engine speed. The solution to this dilemma is probably a deeper sump oil pan with more oil. But let’s float an alternative solution.

We’ve seen this oil pressure drop happen often with big-block Chevys but it can occur with any engine. In most cases, the engine is fitted with a larger capacity aftermarket oil pan. For this example, we’ll use a seven quart capacity. The engine builder fills the engine with seven plus another for the filter. Later, with the engine running at high rpm, this extra oil turns into foam, which is easily compressed in the oil pump – which creates the lower oil pressure. The solution is to simply reduce the capacity by a half-quart at a time until the oil pressure stabilizes at high speed. That’s the engine’s way of telling you what it wants. It’s that simple but it’s amazing the number of engines running right this moment with over-filled sumps.

5. Improper Flat Tappet Cam Break-In

This can be potentially deadly to your engine because of the metal debris that wears off the dead lobes and lifters. Once this occurs, the common response is “all you have to do is change the cam, lifters, oil, and filter and you’re ready to go.” That is not even close to what you have to do. When a lobe failure occurs, you won’t realize there is a problem until the engine has run for at least 15 to 20 minutes. The first indication might be when the rockers start clattering due to lost preload or excessive lash. By this time, quite a bit of metal has circulated throughout the engine for long enough that no number of oil changes will repair the damage.

More importantly, the rod and main bearings have been subjected to all this debris in the oil and it’s a guarantee that the bearings are damaged enough that they will need to be replaced. But even with a tear-down, you must remove the cam bearings (at least with most engines) in order to ensure that all that metal has been removed with a thorough hot tank cleaning.

So how do you avoid suffering from FLS – Flat Lobe Syndrome? We have a procedure that begins with using high-quality break-in oil like the stuff from Comp, Driven Oil, Lucas, Amsoil, or others. Next, we pressure lube the engine just before startup, ensuring that all 16 rocker arms have oil. Next, we use lightweight valve springs or low ratio rockers to prevent excessive spring pressure on the lifters. This means removing the inner spring on dual springs until the cam is broken in. Then the inners can be re-installed. It’s also crucial to vary the engine speed between 2,000 and 2,500 rpm for the first 20 minutes of engine run time and never let the engine idle in those first crucial minutes. The reason for this is to improve the splash oiling of the lifter/cam interface. Higher engine speeds ensure that plenty of oil is splashed around to lube the lifters. Following these suggestions along with correct ignition timing and air-fuel ratio during break-in will drastically improve that flat tappet cam’s chances of survival.

6. Spark Plugs with Melted, Damaged Electrodes or Aluminum Flakes

This is mainly for power-adder engines like nitrous, supercharged or turbocharged engines but we’ve seen nasty looking spark plugs even with normally aspirated engines that foretell evil doings in the combustion chamber. Mangled spark plugs have been called the fusible link in the combustion chamber, but often the damage to the plugs is quickly followed by greater carnage to soft aluminum pistons, combustion chambers, deck surfaces, head gaskets, exhaust valves, and other consumables when the heat is on. This is usually the result of an incorrect tune with too much timing, insufficient octane, or a too-lean air-fuel ratio. Other causes can be traced to the use of an incorrect spark plug. The most common error is using a projected nose spark plug where the longer ground strap becomes a glow plug – which can cause pre-ignition that is often instantly fatal.

Reading spark plugs is a bit of an art form and there are several tuners who are very good at it. But anyone with a willingness to pull a plug and put it under a strong spark plug magnifier can learn a few things and also perhaps save their engine. Tiny black specs on the white ceramic insulator are indications of detonation. If you see little shiny specs of metal – that’s most often aluminum that has melted off the piston or combustion chamber. If caught soon enough, you can calm this cylinder down with more fuel, less timing, higher octane fuel, a cooler plug, or a combination of all of the above that might prevent further damage. But the only way you’ll know is to pull all the plugs and look at them – often. With enough experience, you will soon learn which cylinders are the trouble-makers.

7. When it Rattles – Lift!

Detonation can be a deadly result of some kind of tuning problem or perhaps just low octane fuel and too much timing or compression. Whatever the cause – the best thing you can do is lift off the throttle. Detonation is an uncontrolled, high-pressure spike in the cylinder that can cause significant engine damage. Forged pistons can handle a little bit of detonation – but cast or hypereutectic pistons are especially vulnerable. We’ve seen hypereutectic pistons physically separate right below the oil ring land. It’s happened to us and the result is damage that requires a complete rebuild – and that’s only if we’re lucky. Essentially that pinging that you hear is the pistons slapping hard into the cylinder walls. That is not pretty and certainly not conducive to making power.

Some enthusiasts tend to down-play detonation but that’s not smart. Even if we discount the potential damage, engines don’t make power when they’re detonating. Regardless, detonation is a serious threat to long engine life. Causes of detonation are multiple. If the engine’s too hot, the heat will increase the temperature of the incoming air and require a higher octane fuel than you have on board. Every 25 degree increase in inlet air temperature requires a full point of octane to control. Think about that when the inlet air temperature is 135 degrees. Other causes can be too much compression, not enough octane, over-advanced ignition timing, poor mixture distribution, and at least a couple dozen more causes.

In some cases, you may not even hear the detonation – but that doesn’t mean it doesn’t exist. I know a few older enthusiasts who physically can’t hear the rattle – their hearing in that audible range has long-since disappeared. In that case, the quick fix is to bring along a younger friend who can hear what the engine is saying. It’s talking to you but you have to listen. The engine is telling you it’s hurting. It’s up to you to fix it before it breaks.

8. Hydraulic Lockup

You’ll notice this when the starter motor begins to turn the engine and then suddenly stops. Like the old wheeze that it’s not the fall that kills you but the sudden stop at the end – the same is true with hydraulic lockup. That sudden cranking stop is a clear message your engine is suffering. We recently spoke to a friend who had just taken on the challenge of repairing a big-block engine that the customer wanted to run with a complete Hilborn mechanical fuel injection. The owner’s claim was the engine “used to run, but lately we’ve had problems.” Later, the customer admitted they’d suffered two bent connecting rods. My friend quickly realized that was due to the crankshaft attempting to push the pistons past a load of incompressible liquid.

A sure indication of trouble is when water or coolant leaks out of the spark plug hole. That’s a bad sign. The most likely causes are either a blown head gasket or a cracked cylinder head or cylinder wall that’s allowing coolant into the engine. When head gaskets fail, you must do more than just replace the gasket. To prevent a reoccurrence, the search must include locating the source of why the gasket failed in the first place. Common issues include incorrect torque loads or perhaps uneven deck surfaces. The latest generation of multi-layer steel (MLS) gaskets is an excellent choice for engines with head gasket sealing issues. But regardless of the source of the problem, liquids in the combustion space are universally a bad omen – unless your idea of fun is burning monster loads of nitromethane.

9. Noise at Startup

It’s that clanking or banging sound when the engine first fires that might be a very serious warning sign. Most everybody knows what a rod knock sounds like. It’s that heavy thumping sound that comes from deep inside your engine. Some performance engines will do this when they are cold – and the noise can be traced to piston slap. The original ZZ350 Chevy crate engines from 20 years ago had this problem and customers were afraid the rods were banging around when it was, in fact, piston slap. We built a 355c.i. small-block with 2618 alloy forged aluminum pistons with 0.005-inch of piston-to-wall clearance and that engine was incredibly noisy for the first five minutes of cold running time. The engine was so noisy we actually took it apart only to learn it was the pistons making the noise as the rod and main bearing clearances were fine.

We’ve also had a hydraulic flat tappet lifter sound exactly like a rod knock when the lifter had pumped down and the extra clearance caused a heavy knocking sound. But apart from these anomalies, a heavy knock after engine abuse can often let you know there is a problem, especially if the noise is accompanied by a loss in oil pressure and shiny bits in the oil. That combination of a heavy thumping and a loss in oil pressure is a notice written in bold letters that your engine may need emergency surgery.

10. Death Smoke

They say that smoking isn’t good for humans and the same can be said for a smoking engine. A building cloud of blue engine oil smoke is the engine’s way to telling you that something is amiss. The way the engine smokes can often also be used to help diagnose the problem. If the engine smokes on startup and also tends to puff on deceleration – then the engine is trying to tell you that the valve guide seals have gone bad – perhaps exaggerated by loose valve guide clearance. We’ve also seen intake gaskets that are not sealed properly at the bottom of the manifold that can pull oil from the lifter valley into the intake port and cause the engine to consume oil.

If the smoke is more pronounced under acceleration, that tells you that the rings may be the source of the problem. Generally, this is a common problem with high mileage engines and not entirely the fault of the rings because the cylinder bores are probably worn rather badly as well which will contribute to the oil consumption issue.

Also falling under the category of gases emitting from the tailpipe, steam or white smoke usually means head gasket or cracked heads are admitting coolant into the combustion chamber. This can be caused by detonation – or – almost as often is the result of heavy detonation that can cause serious engine damage such as broken cylinder walls. We’ve lost an engine that way, too. It’s not pretty.

11. Catastrophic Oil Pan Failure

We thought we’d toss in an extra one just for fun. In this case, no diagnostics is necessary. When the connecting rod or piston are hanging out of the side of the pan, or there’s a giant hole in the pan and oil is splattered all over the undercarriage of your car, the problem – as they say – is obvious. There’s not much left to do except mop up the oil and yank the motor. This is when you transition from a END (Engine Near Death) experience to using DeForrest Kelly’s iconic line from Star Trek: “He’s dead, Jim…”

About Jeff Smith

A clue into how long Jeff Smith has been writing technical automotive stories might be his following of second generation readers. Writing continuously for nearly 40 years, his focus with Xceleration covers all things technical. His collection of cars includes a bevy of Chevelles and El Caminos. When not writing about cars, he likes to spend time with his wife Valerye, children Amber and Graham, and granddaughter Celeste.