Keeping older cars and bikes running in their later years can be a testing experience; one of the most irritating issues old engines can develop is lifter tick, AKA noisy lifters.
In this article, I will explore the options when working out how to quiet noisy lifters, and cover the available solutions to solving the problem.
Luckily the vast majority of lifter noise is caused by a simple and easy to solve the issue which you can buy off-the-shelf treatments for.
So, read on and your engine could be purring quietly again in no time, and without too much cost.
What is a valve lifter?
Firstly, it makes sense to explain what a valve lifter (or tappet) actually is so you can gain some context on why your engine, and your ears, might be suffering from lifter tick in the first place.
You probably know the basics of how internal combustion engines work, mixing fuel and air and then igniting it with a spark to accelerate a piston. If you really break it down to the basics, it’s just a nice way of converting fire into a rotating shaft.
When we refer to valves in the context of an internal combustion engine, we are talking about the system designed to open and close passageways which allow airflow into and out of the combustion chamber (or cylinder) where the piston travels up and down.
It’s important that these valves open and close the right amount, at the right moment, and for the right length of time while the engine is running.
The intake valve opens as the piston descends which allows the air and fuel mixture to be drawn in, the mixture is then compressed by the piston as it comes back up the cylinder, it’s then ignited by a spark forcing the piston back down the cylinder, and finally, the exhaust valve is opened again as the piston comes back up to push the exhaust gasses out ready for the cycle to repeat.
The thing that controls valve timing and lift is the camshaft. This rotating shaft has precisely machined cam lobes, shaped to maximise efficiency. The cam lobes actuate the valves as it turns with a lifter as an intermediary to fill the slack.
To keep the valve stem contacting the lifter with no slack, between the lifter and valve is a valve spring, the force of which returns the valve to the closed position when it’s not being actuated by a cam lobe.
Modern-day engines are highly complex by design, and at no time is this more obvious than when you’re looking at a valve train.
Engineers have been refining the mechanical system described above for many years. Now we have such a huge focus on efficiency, reducing emissions, and maximising performance, so the tolerances have become much tighter for valve trains.
A valve lifter is just one small part of the complex arrangement. The lifters job is quite simply to act as an intermediary between the cam lobe and valve, picking up the slack and lifting the valve out of its seat following the cam profile.
It sounds like a very simple job, and to the main extent, it is. Valve lifters come in a few common formats which I will explain below.
Solid valve lifters are the original solution to lifting valves. The clue is in the title with these, they tend to be solid metal cylinders which are bucket-shaped to allow for a metal shim to be securely positioned.
This shim needs to be replaced as a service item as it wears to maintain the optimal tolerance as it can wear down below the optimum thickness for smooth engine running.
Solid lifters are still used today on high-performance engines for the precision they allow.
Being solid, they are not susceptible to being compressed so can be used with particularly aggressive cam profiles and stiff valve springs to return them. These allow for a more efficient valve sequence, preventing valve bounce at higher rpm.
With solid lifters comes the opportunity for higher performance and faster valve movement to get the timings absolutely precise for optimum performance.
The drawback is that engines with solid lifters require regular valve train maintenance which is very labour intensive.
If not appropriately serviced then the performance of the engine will suffer, the lifters will become noisy and tick loudly, and this could lead to more serious engine damage if left unchecked.
The maintenance on solid lifters involves stripping the head on the engine and measuring the clearance of each valve with a feeler gauge replacing each individual shim to meet the correct clearance for the engine.
- Allows for high revving performance engines
- Allows for greater efficiency
- Simple design
- Low original cost of manufacture
- Inherently noisy valve lifters
- Requires regular, labour-intensive maintenance
An example of a modern engine with solid lifters is the S54 inline-6 found in the E46 M3.
Hydraulic tappets are very common in modern engines; they were designed to both reduce maintenance and reduce valve lifter noise which is inherent with solid lifters.
Hydraulic lifters have a simple but clever design. They are effectively two buckets, open ends facing, one tightly slotted inside the other so able to expand or contract.
There is a tiny hole on the side of each tappet which allows oil to flow inside the hollow chamber inside, effectively turning it into a small oil reservoir.
When the engine is running, the oil pressure from the pump keeps these hydraulic tappets inflated and full of oil, when filled with pressurised oil they expand to fill the gap between the cam lobe and the valve to pick up all the valve train slack.
This ingenious solution removes the need to measure and replace valve shims as the lifter can fill whatever size of gap it needs to, effectively self-adjusting.
The hole in the side of the hydraulic lifter which lets oil in or out is very small, so as oil is hard to compress when the camshaft lobe pushes down on it, it behaves almost as though it were solid.
The truth is that hydraulic lifters are not as solid as traditional solid tappets, there will always be some compression with hydraulic lifters, and at a certain level of engine tune, they can become a limiting factor.
But for the majority of cars and bikes, they are solid enough to do the job, and more than make up for it with reduced maintenance. An example of an engine that uses hydraulic lifters is the M42B18 inline-4 engine found in the BMW 318is E30.
The only other downside to hydraulic tappets is their tendency to get gummed up with oil deposits over time reducing their ability to expand and maintain their correct size.
If you end up with sticky lifters which fail to expand, then lots of slack will be present in the drive train leading to some serious loud ticking lifter noise.
- Self-adjusting to greatly reduce maintenance
- Inherently quieter valve lifters
- Noisy lifters when worn or gummed up
- Reduced performance when worn or gummed up
- Limiting factor on highly tuned engines
What causes lifter tick?
The source of the lifter tick is almost always some form of slack in the valvetrain. Where there is slack, there are moving metal components clacking together with too much clearance between them.
As previously mentioned, there are two main types of valve lifters. If your engine is suffering from noisy lifters which create a constant knocking, tapping or ticking sound then the source of the problem very much depends on which type you have.
If you have a modern engine, either a petrol or a diesel which features hydraulic lifters then it is most likely that your lifters are gummed up with oil deposits preventing them from functioning correctly.
What tends to happen is that the oil deposits build up inside and around the hydraulic tappet preventing oil from entering them to inflate them to size. If they are not inflated to fill the slack, you will experience noisy lifters.
Even if your vehicle has a full service history with all of the manufacturer’s recommended oil and filter changes ticked off on time, if it has hydraulic lifters then at some point in its life it will likely suffer from lifter tick.
This is partly due to pressure on manufacturers to offer their customers engines with minimal maintenance obligations.
With this in mind, it’s recommended to give your car more regular oil services than the manufacturer suggests, and consider flushing out your engine every so often to get rid of deposits.
One of the early signs to look out for is noisy lifters when you first start the engine from cold. As the engine sits with no oil pressure, hydraulic lifters will deflate as oil escapes out of their hollow reservoir.
Hydraulic lifters in good health should reinflate very quickly when the oil pump is running, even from cold. Gummed up or worn out lifters can take a while to inflate and may only do so when the engine oil has warmed up.
Be aware that hydraulic lifters can simply wear out over time, sometimes they can just be past their best and become noisy in older higher mileage engines.
However, if left gummed up and ticking for long periods of time, they can be damaged, or other even more expensive parts of your engine’s valve train can instead lead to the same noise as noisy lifters make.
If your vehicle is an old classic or is sporting a high revving performance engine then you’ll likely have solid valve lifters.
Noisy lifters or a constant ticking sound coming from your engine can be inherent with these types of engines and they run louder and more ticky in general with more valvetrain noise.
This is partly because there’s nothing to take the shock out of the moving metal parts which hydraulic lifters somewhat do.
However, if your noisy lifters are especially loud or have become louder over time then it is definitely signs of a problem.
It can often be that your engine is due a service which involves checking valve clearance and adjusting by way of shims.
If your engine has solid lifters and has been poorly serviced or maintained and run for long periods of time with poorly adjusted valves, then it can lead to excessive wear on other more expensive engine parts which will again lead to that noisy lifter sound.
How to quiet noisy lifters
Prevention is often better than the cure so the best method to quiet noisy lifters, or rather, keep lifter noise from becoming a future issue, is to keep your engine properly serviced.
I would recommend oil servicing more regularly than the manufacturer recommends as they are motivated to extend service intervals to (and sometimes beyond) the sensible limit to make their vehicles more attractive to customers.
I also believe that they are happy to accept the resulting reduced engine lifespan as it works out to be planned obsolescence for them. You need a car, so you’ll be back to purchase another new car in the future when your current one’s engine wears out.
Giving it a good run
If your car or bike is just starting to have noisy hydraulic lifters despite proper servicing, it can quite often be down to the way you use it.
Many cars, both diesel and petrol-engined are used exclusively for shorter journeys or even worse, short and infrequent journeys.
It may seem counter-intuitive but if this describes your scenario then fixing noisy lifters might be as simple as taking your car or bike on a long journey.
You might find that a thorough warming up of the engine for a prolonged period of time can quiet noisy lifters considerably by effectively flushing warm oil through the whole system helping to prevent lifters from gumming up.
Of course, to use this trick most effectively it should be combined with an oil and filter change beforehand.
Be aware that if your car or bike has solid lifters which are suffering from lifter tick then no number of oil changes will quiet noisy lifters that are already noisy.
In the case of solid lifters, I would also advise against taking any long-distance journeys prior to having your valve clearances adjusted.
Doing so could lead to unnecessary wear on the engine which could be easily avoided.
Engine flushing to clear oil deposits
Regardless of what type of lifters your engine has, it’s a great idea to run some engine flush through your engine along with an oil change from time to time.
Oil deposits can build up over time in your engine leading to various issues down the line.
Engine flush contains specially formulated detergents which help to break up these deposits so they can escape along with the oil when it’s drained for replacement.
If you have noisy hydraulic lifters then engine flush can be particularly effective when it comes to trying to fix noisy lifters.
As pointed out, oil deposits are one of the main sources of noisy tappets and engine flushing is a good way to keep tappets from becoming gummed up.
There are a couple of great off-the-shelf engine flush products which are readily available to buy. See a couple of my recommendations below.
Wynn’s Engine Flush: http://ebay.us/vT3q7y
Forte Engine Flush: http://ebay.us/EoXZyw
Best additive to quiet lifters
Another neat trick to quiet noisy lifters is to use special oil additives to reduce lifter noise. This is another one which is aimed at those with noisy hydraulic tappets rather than solid ones.
There are a few companies that have developed additives specifically formulated to reduce noisy lifters.
These additives are intended to be added to engine oil each change and modify the properties of the oil slightly to make it more hydraulic lifter friendly.
These additives are intended to keep hydraulic tappets clean and clear of oil deposits, ensuring the duct which allows oil to flow in and out is free.
As a side effect, they can also keep various other oil passageways clear to ensure your engine is being effectively lubricated to avoid wear.
As far as the best additive to quiet lifters is concerned, the main one I’d recommend is Liqui Moly Hydraulic Lifter Additive. This one, in particular, is formulated very specifically for fixing noisy lifters rather than being a more general additive.
The only thing to be aware of with this additive is that it is not for use with wet clutches (found on some motorbikes). If you’re looking to reduce lifter noise on your bike, then make sure you check this first.
Liqui Moly Hydraulic Lifter Additive: http://ebay.us/jqo3TG
There are a couple of other good additives which have a similar effect but they are designed for more general use in mind.
They are intended to improve your oil’s ability to lubricate and reduce engine wear too.
These can be ideal for older engines or engines with solid lifters as they will act as a prevention for noisy lifters. Sadly though, it will not fix noisy lifters on an engine with solid lifters.
STP Synthetic Oil Treatment for Petrol & Diesel Engines: http://ebay.us/vWo4bC
Wynn’s Super Charge Oil Treatment for Petrol & Diesel Engines: http://ebay.us/pwqCAL
Valve clearance adjustment
If your car or bike has solid lifters then you will need to follow the manufacturer’s recommended interval for valve clearance adjustment.
As covered earlier in the article, solid lifters rely on the clearance being set correctly manually using shims which wear over time causing noisy lifters.
Unfortunately, when it comes to high-performance engines with dual overhead camshafts this can be a very involved process which in most cases is best left to an experienced mechanic. It often involves specialist tools for each different engine which can also come at a high cost.
If your car or bike is a classic with a single overhead cam or a pushrod design, then it may be a job an amateur mechanic can take on DIY style with a feeler gauge.
Generally, you can expect an engine with solid lifters to require a valve clearance adjustment at around every 20-30k miles.
If you have hydraulic lifters, they would not benefit from a valve clearance adjustment as the lifters are designed to be self-adjusting and cannot be adjusted manually anyway.
If all else fails and none of the above solves your noisy lifter problem, the last resort will certainly fix lifter tick. However, it comes at a high cost.
If you have hydraulic lifters and all of the above hasn’t worked, it may be a sign that your valvetrain is simply worn out. If you can’t quiet noisy lifters then the only remaining option is to replace them.
Replacing hydraulic lifters can be very involved and usually involves a full top-end strip-down and rebuild of the engine with many new replacement parts.
With solid lifters, a sign that you’re in need of a full top end rebuild is when you can no longer adjust valve lash to spec with shims.
Lifters being worn to this level can usually point to poor engine maintenance in the past and it’s unlikely that other more expensive components in the top end of the engine, such as the camshaft will have avoided damage.
A top-end rebuild is a similar job for both engines with hydraulic and solid lifters and with the man-hours involved mean the bill can be unexpectedly large before the cost of parts is even totted up.
If you are in a situation where your top end is showing signs of wear, it could spell wear to the bottom end of your engine too such as the crank.
At this point, it’s worth considering a full engine rebuild or it will likely be more cost-effective to undergo whole engine replacement using a lower mileage donor car which has been involved in an accident for example.
Disclaimer: This post contains affiliate links.