Information Related To LS1, LS2, LS3, L76, L98 & L77
The LS engine range consists of modern pushrod V8s, known for their reliability. However, when issues do occur, car owners may ask questions such as “What caused the problem?”, “What could have been done to prevent it?” and “How can it be prevented from happening again?” This article aims to help car owners understand some problems they may face with these engines. If you are looking for prices for LS engine reconditioning look here
Lifter Problems
One of the most common problems LS engines face, especially in older, modified engines, is hydraulic lifter failure. The first symptom may be a knocking on one cylinder while idling or a squeaking sound. If this happens, the car should be minimally driven. Or even better, transported to a workshop or back to the place where the work was done. That is likely the cheapest place to have it fixed.
Don’t keep driving with lifter noise.
Driving a vehicle like this can harm the camshaft lobe. This damage can lead to costly repairs. The squeaking noise you hear is metal scraping against metal. The metal spread through the engine will also lead to cam and main bearing damage and metal deposits in the oil pump. This metal buildup damages the oil pump and further increases damage to the engine.
Sometimes, cars are driven for weeks with a knocking sound or aggressively to fix the problem. This can turn a basic problem into a situation where the engine must be completely taken apart and rebuilt. This can cause what started as a $2000 repair to turn into a $9000+ repair. In addition to cam lobe damage, the lifter can break apart. The roller wheel may bounce around the engine. This can cause damage or even crack the engine block. Sometimes lifters can break, and the tapping can progress to the fall apart stage on the day the tapping is first noticed.
Possible causes of lifter failure
Lifter failure often happens for several reasons. A worn lifter is a common cause. Ineffective lubrication can also lead to problems. This can occur due to engine oil deterioration. Low oil pressure, whether temporary or permanent, may be a factor. Worn bearings can contribute to low oil pressure as well. Additionally, dirty oil can cause lifter issues. Faults in the engine block tunnels may also play a role. Worn or faulty lifter buckets can lead to failure too. High RPM when the engine is cold can cause damage. Lastly, softened valve springs that need replacing can contribute to lifter failure. Sometimes, the tapping noise can come from a spring-loaded lifter. If its spring mechanism gets jammed, it becomes solid. This issue is most common in older engines. At times, the surface of the lifter roller wheel can fail. This often happens due to poor oiling in the lifter bore. When this occurs, it creates friction on the cam lobe. This friction can cause a squeaking noise and damage the cam lobe.
Replacement Lifters
Aftermarket high-performance lifters can be used as replacements. However, they tend to fail more often than expected. The best way to avoid expensive damage is to be alert and take your car in for repairs when issues arise. Please do not drive the vehicle. Doing so may cause more damage. Even if the engine is still under warranty, it will not cover any damage. This is especially true if you keep using the engine after it has failed.
The best preventative action is to listen for new noises often and don’t ignore any new tapping noises. When the engine has done over 100,000 km, change the lifters immediately. Changing them requires the heads to be removed, which means the engine will also need new head gaskets and cylinder head bolts.
All high-lift aftermarket camshafts with a lift over 560 thou (thousandths of an inch) will have a higher lifter failure rate. This is because these require higher spring pressures to prevent valve float, which puts extra pressure on the lifter. Using light-rate springs is not a solution. There is an increased rate of problems that result from valve float, which creates hammering of the valve train. The main message is if you want to enjoy the benefits of a cam upgrade that gives you significantly more power. It compromises the overall engine reliability because of the extra rpm range. Once a car is modified for better performance, the driver must pay attention to new noises. They should also protect the vehicle from any additional damage.
Link-bar Lifters
We use them in our Sports Sedan because it needs to rev to 7500rpm reliably for 300km races. But road cars we find are better off with LS7 Lifters and new buckets.
Link-bar lifters are not a solution; they may help with very high rpm valve float, but that’s all. The bars prevent the lifters from spinning in the bores. Some engineers believe that the lifter guide system from GM is better at controlling lifter vibration. If the guide and buckets are not worn, the lifters cannot spin. The link-bar lifters let the lifters vibrate much more than the factory system. This can contribute to reliability problems with link bars.
Noisy hydraulic lifters can be caused by several factors.
None of these issues are due to a defective lifter. Therefore, they are not covered by the manufacturer’s warranty.
Particles in the oil getting stuck between the lifter plunger and the lifter body.
This is the most common issue and this can cause the plunger to become stuck down.
The clearances between the plunger and body of a Hydraulic lifter can be as little as .00012″, .003mm. or 3 Microns (1/30th of a Human Hair). Any particle larger than this circulating in the oil can flow through the lifter and jam the plunger in the body. This is especially common after a rebuild. Particles can be left in oil galleries or crevices. These particles may then find their way into the lifters. Replacing the lifters usually solves the problem. The lifters or the filter have likely captured all the initial dirt.
Note that some “Racing” oil filters only filter down to 27 microns and may not be suitable for hydraulic lifter engines.
Aeration of oil in the pressure chamber of the lifter can cause noise.
This may be the result of air in the high-pressure chamber of the lifter affecting the valve train lash. When this occurs, valve closing velocity is increased, which causes the noise. Air can be present in the lifter at shutdown due to an aerated oil condition. Or it can be ingested into the lifter during a cold start from a suction side leak at the oil pump or oil pump pick-up tube o-ring. The level of oil aeration affects lifter noise. Oil viscosity also plays a role. Additionally, the time it takes to reach oil pressure is important. Engine speed can influence the noise as well. Finally, the design of the lifter is important as well. When air enters the high-pressure chamber, it will slowly escape through the tight clearance between the plunger and the body. Aeration can be caused at high RPM by low oil levels or an incorrectly designed oiling system. This will make lifters “spongy” and significantly affect the valve train operation.
Lifter Roller Wheels are Damaged
This can be caused by impurities in the oil starting the surface to be scuffed. Or the valve spring and high rpm allowing the pushrod to bounce the lifter. So,n weak valve springs can be the cause. Or a mechanical over rev may have damaged the springs and/or caused the lifter wheel to bounce.
Dropped Valve Seat
An event we have seen happening more frequently lately is dropped valve seats.
The valve seats are cast iron and pressed into the aluminium heads. The seat can drop because cast iron and aluminum expand at different rates. This often happens after many heat cycles and possible overheating. This makes the valve protrude, and the piston hits it. It can cause catastrophic damage, e.g. rod out the site of the block. It often happens on startup after the engine has cooled slightly. In some cases, owners may only have a bent valve.
There is no way to predict the occurrence of this problem. It can’t be identified until it happens. When heads are CNC ported, the seats are optional, which isn’t a cheap extra, or new heads can be purchased. LS3 Heads are still available for reasonable prices. We offer new LS3 heads, CNC-ported LS3 heads, and CNC-ported used heads with new valve seats fitted.
Cam Bearings
Valve Spring Problems
Broken Valve Spring
The benefit of a dual spring is that if one spring breaks, the other spring will keep the valve up. This helps prevent the valve from falling into the engine. If a single spring breaks, a valve is commonly dropped, which causes considerable damage. Sometimes, the valve is held up by the valve locks, and the spring collapses.
Damage caused by a Broken Valve Spring
The damage from valve spring failure depends mainly on when the spring breakage is detected and how it is driven after the breakage. If an engine is driven for weeks or thrashed on a broken spring, extra damage is likely done. The most common issue is a bent valve. This problem requires removing the cylinder head. A new valve must be installed, along with a new head gasket and head bolts. If the valve head breaks off, this will result in much more damage. It is important that you do not drive the vehicle at the first signs of a broken spring. If you must drive it, keep the engine speed below 2000 rpm. This is much safer for the engine, especially at low RPM.
Symptoms of a broken spring
Symptoms can vary. One common sign is an instant change in the engine. This change often shows as a noticeable loss of power, especially above 4000 RPM. It may sometimes be apparent as a miss under load. Other times, there is a constant miss. If a valve has dropped, it will be far worse than that: the engine will seize, i.e., it will not be able to rotate.
Springs break at all stages of their life.
Some new cars have broken springs within 5000km, and some with factory springs last 300,000 km without breakage. It depends mainly on luck, but one thing that can help spring life is avoiding high rpm on cold springs, i.e. Always warm up the engine by driving gently until it’s at full operating temperature.
Valve Float
Valve floating occurs when the valve springs lose control at very high RPM. This can happen, especially during burnouts, when the engine hits the rev limiter. The shock harmonics from this action can severely affect the springs. This ages them fast and will cause much more frequent breakages.
Engine Overheating Effect on Springs
Another cause of trouble is a spring severely overheating from an overheated engine. If the motor is ever severely overheated, replace the valve springs.
Mechanical Over-Rev
Damage can also occur from "mechanical over-rev events. These events happen when a driver downshifts into the wrong gear. This mistake can push the engine’s RPM well above its rev limiter. There can be damage from the valves floating severely and hitting pistons, as well as a range of other things, including valve seat damage. A race team in the USA discovered something interesting. They found that valve springs in race engines that were not overrevved lasted 10 times longer. In contrast, the valve springs that were occasionally overrevved did not last as long. This highlights the importance of managing engine revs for better performance and longevity. Valve springs can become worn out from just one over-rev. This can cause them to lose pressure and become more likely to break.
Change your springs occasionally.
When upgrading your camshaft, it is advisable to replace the springs every 50,000 kilometers. Additionally, check the springs when they reach 40,000 kilometers to ensure they are maintaining proper pressure. If the engine is regularly revved over 6400rpm, it is best to check and change springs more often. The main thing to recognise is that valve springs have a finite life and a variable lifespan depending on their treatment.
Rocker Trunion Bearings
The rockers sit atop the valve train and transfer energy from the pushrod to the valve. They can develop a sideways slop from their bearings, which can cause problems with valve spring breakages due to harmonics. They can also fly apart with their needle bearings falling out and ending in the oil pan. It’s best to inspect them for signs of sideways slop.
Rocker bearing upgrade
We use CHE bush kits that you can buy and install in the factory rockers. These kits reduce sideways slop and improve the vertical motion of the rockers. This is an excellent modification to the stock rockers.
Timing Chain Tensioners – VE-VF
Many early model timing chain tensioners can break. This often causes few symptoms. Usually, the issue is only noticed during a cam upgrade. But it isn’t good, the bits from the tensioner can be scattered around the engine.
Some people change timing chains when doing cam upgrades, but it is rare for LS timing chains to snap. But if they do, it can cause a lot of damage. Replacing the timing chain is not a simple job at the front of the engine. It requires the sump to be removed and a fair bit of extra work to be changed. Often, the oil pump is also replaced at the same time, so the cost is around an additional $1500. Timing Chains can snap, but it’s rare and usually from severe situations like a mechanical overrev.
Cracking Cylinder Sleeves
Please read our article about Core Shift and how it happens at the factory. The LS blocks are aluminium with cast iron sleeves. When manufactured, these sleeves are bored where they sit, often resulting in thickness variations from side to side.
This presents a weak spot in the cylinder wall, prone to cracking when pushed hard or with a boosted engine. They may also crack when the engine is overheated or after significant cylinder sleeve wear.
Sleeving at Oztrack
We can remove the old sleeves and install higher-quality ones in the exact “blueprinted” position. This can then give an engine a new life.
Clutch VE V8 2006 To Around 2009.
Holden changed all the clutches to the LS7 Clutch in September 2010, and likely all LS3 manuals have it. Before that, the factory slave cylinders commonly fail. This issue causes the clutch pedal to stay down after high load and high RPM. When it starts to fail, the clutch will slip at high RPM under load. The fix for this is not to replace the clutch alone but also the slave.
Vigilance
We cannot emphasize enough the importance of vigilance with your LS engine. Maintain the car’s oil in top condition <8000 km old and top-level synthetic oil of around 5w-30. If there is a new noise, get the engine checked straight away. Having a car towed off the road to a workshop can be inconvenient. It takes time and money. However, it can also save you money in the long run. This is true even for vehicles that have warranties for the parts that fail. The person in charge must take all reasonable steps to reduce damage to the engine and its parts when a failure is suspected. Using the vehicle after a defect or fault has occurred will void the warranty for any needed repairs.
Engine Abuse And Its Effects
No engine can withstand abuse from long stints near or on the rev limiter, e.g. during burnouts. In circuit racing, engine oil and gearbox temperatures often exceed safe levels. This happens unless special coolers are installed. As was explained above, the frequent use of the engines near the rev limiter will age their components much more quickly. Even an engine with all new parts could have any of them fail in the early period from harsh usage. This issue can be quite simple. It happens when an engine does not reach its full operating temperature. If you use the engine at full load and across its RPM range before it warms up, it can cause problems. Thrashing an engine early in its warm-up cycle will age its components much faster.
Overheating can cause lasting damage.
If the engine is overheating, shut it down immediately. Allow it to cool, regardless of your location. Arrange for assistance, and do not continue driving. Continuing to drive can cause damage to engine parts. Even if the car cools and seems OK, it isn’t. It is one significant step closer to failure. Many vehicles have issues with faulty radiator caps. Blocked coolant recovery pipes are also common. Some cars use low-quality replacement radiators.
Additionally, cracked radiators can occur near the cap and at the bottom. Bad thermostats, bad quality replacement water pumps, air bubbles in the coolant (cars never setup correctly with coolant levels). Never replace your water pump or radiator with items that are not highly recommended. We aim only to use GM genuine water pumps or NATRAD radiators.
Oztrack offers an engine rebuild service for the LS range of engines.
We commonly rebuild with far better-than-standard parts and do cam upgrades. We also have in-house engine machining services, including a Sunnen Honing Machine and a CNC Boring & Surfacing machine.
These are priced from $9900, and we can complete these jobs precisely and quickly.
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