Our main stock holding of Pistons are from the Nural / AE range. We do have other brands in stock and can source Mahle & KS available for next day delivery. We also have access to forged pistons for performance applications.

Pistons UK
How do Pistons work in a engine?

How do Pistons work in a engine?

Pistons are located in the engine block and move up and down the cylinder. The distance travelled is set by the crankshaft & conrod length, this measurement is known as the 'Stroke'. The piston and its rings perform a gas-tight seal. When the piston moves upwards, the air & fuel mixture inside the combustion area is compressed. When the piston meets the top of its stroke the fuel mixture combusts, in a petrol engine, the air / fuel mixture must be ignited by the spark plug. The explosive force of the combustion forces the piston downwards which in turn rotates the crankshaft resulting in power output.

Piston Rings

Piston rings are located on the side of the piston and run around the circumference of the piston forming a gas-tight seal. When piston rings are worn compression can be lost and you may notice blue smoke from the exhaust. The blue smoke indicates that oil is being burnt in the combustion area. This is a common sign of either worn valve stem seals or piston rings. We stock Goetze, Schottle, Hastings, Tarabusi & NE Europe rings. On conventional modern car & light commercial engines it is likely to have three rings per piston. The top 2 are the compression rings and the bottom is the oil control ring. Certain engines have more or less rings depending on the piston design. Great care should be taken when assembling new piston rings that any tapers, keystones & cutaways match that of the piston ring lands.

piston rings
piston liners & kit sets

Cylinder Liners

We stock Goetze & Tarabusi Liners. Not all engines have a typical wet liner and do not have to be replaced. The engine reconditioner will know this and can often bore your block to an oversize. Always check that we have stock of the oversize pistons before having the block bored. Some engines like the Rover K-Series have a wet liner that is removed from the block and replaced with the piston. In some cases, the block may be to badly damaged to be bored or oversized pistons may not be available. In this case, the engine reconditioner could sleeve the original block with a dry liner to bring it back to a specific size.

Diesel Piston Failure Chart - Troubleshooting

Piston seizure, with severe damage to the top land
piston seizure

Symptom: Loss of power. Engine noise. Fumes from the engine breather.

Cause: Exceptionally high combustion temperature. Malfunction of piston oil cooling jets (in engine incorporating this equipment.) These cause seizure close to the piston crown, which may result in piston ring damage and progression of seizure down the piston skirt.

Remedy: Check adjustment of fuel injection equipment and correct as necessary. Rectify or replace damaged cylinder components. Ensure any piston under crown cooling jets are functioning correctly

Fracture of the Cylinder Liner under the flange area
cylinder liner crack under flange

Symptom: Combustion gases ventilating to coolant, Engine noise, Eventual destruction of liner.

Cause: Incorrect distribution of pressures on liner flange as may be caused by:

• Cylinder block distortion • Incorrect tightening of cylinder head studs.

• Misaligned block counter bore.

• Foreign material assembled under flange.

• Incorrect location of cylinder head gaskets.

• Incorrect liner assembly procedures.

Remedy: Establish cause and take corrective action. Replace cylinder liner and any other affected components

Pitting & Erosion of Liner Outer Surface
cylinder liner corrosion

Symptom: Loss of coolant.

Cause: High frequency vibration resulting in cavitation erosion. This may be promoted by general engine wear or repetitive use for long periods at higher than normal engine loads.

Remedy: Clean and check sealing ring grooves and contact areas. Replace cylinder liner. Ensure that the coolant system is operating at the correct pressure. Use coolant inhibitors as recommended by the engine manufacturer.

Erosion of Piston Skirt adjacent to the Piston Pin Hole & Damage to Cylinder Bore
piston skirt damage

Symptom: Engine noise. Oil consumption.

Cause: Incorrect assembly of circlip. Fitting of used circlips. End pressure transmitted via the piston pin, possibly associated with connecting rod misalignment, tapered crank journals, or excessive crankshaft end float. Foreign material assembled in piston pin bore.

Remedy: Correct any cylinder bore damage. Check for and correct any connecting rod or small end bush misalignment. Check for and correct any crankshaft end float. Replace piston assembly, ensuring that the circlips are correctly located.

Piston Seizure, with severe damage concentrated in the lower area of piston skirt
piston seizure / skirt damage

Symptom: Loss of power. Engine noise. Fumes from engine breather.

Cause: a. Damage concentrated on one face: Lack of lubrication. b. Damage on both faces: Progression of damage caused by lack of lubrication. Insufficient piston to cylinder clearance. Cylinder bore distortion. General engine overheating. Restricted coolant circulation.

Remedy: Inspect cylinder bores and coolant circulation. Correct as necessary. Replace damaged cylinder components.

Cylinder Liner Bore Distortion. Scuffing or Seizure of piston & rings. Carbon deposits on the outside of the liner.
liner distortion

Symptom: Loss of power. Oil consumption. Fumes from engine breather. Piston seizure in extreme cases.

Cause: Cylinder block distortion. Cylinder head distortion. Damaged or incorrectly fitted cylinder head gasket. Incorrect liner fitting.

Remedy: Thoroughly clean the engine block bores. Check for block bore distortion and rectify if possible.

Cracks radiating from the combustion bowl
combustion bowl cracking

Symptom: Cannot be detected during normal engine operation.

Cause: Extremes of temperature applied to piston crown, resulting in thermal shock. May be promoted by exceptionally high engine load when operating in low ambient temperature.

Remedy: Replace damaged components

Piston Ring Scuffing or Localised areas of Pistron Ring Seizure
piston ring scuffed

Symptom: Oil consumption, with possible fumes from engine breather.

Cause: Excessive cylinder surface temperature. Marginal lubrication, particularly during early engine life. Cylinder bore distortion.

Remedy: Rectify any cylinder bore damage. Replace piston rings, also the piston, if necessary. Ensure the complete engine lubrication system is fully primed (oil pump, filter, etc.) Observe running in procedures as recommended by the engine manufacturer.

Piston Ring Land Fracture
piston ring land fracture

Symptom: Loss of power. Oil consumption. Emission of fumes from engine breather.

Cause: Exceptionally high combustion pressures, as may be caused by advanced injection pump timing, overuse of aerosol starting aid, increased compression ratio.

Remedy: Establish cause and take remedial action. Replace piston assembly.

Erosion & Burning of Piston Crown
burnt & eroded piston crown

Symptom: Loss of power, emission of fumes from engine breather. Exhaust smoke.

Cause: Incorrect fuel injection, injection timing, over fuelling, damaged or incorrectly located injector.

Remedy: Inspect and correct fuel injection equipment and timing. Check and correct any damage to cylinder bore. Replace piston.

camshafts, hydraulics, lifters & tappets

Cams & Followers

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Camshafts & Followers

We stock camshafts, cam followers, cam buckets, shims, hydraulic lifters / tappets and rockers arms for vehicles from all over the world, whether it be a car, commercial or marine. We keep high O.E quality products made by Ajusa, Freccia, AE.

engine conrod & main bearings

Engine Bearings

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Engine Bearings

We have a massive range of bearings for same or next day delivery. We stock Glyco, ACL, ACL Race Series, King, Vandervell, AE & Glacier. We also have a huge range of oversizes to suit damaged crankshafts. Camshaft bushes are also available.

gaskets, seals & bolts

Gaskets, Seals & Bolts

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Gaskets, Seals & Bolts

Our extensive range of gaskets, seals and bolts for American, European and Asian vehicles is the best in the UK. Whether it be Car, Commercial, Plant or Marine. We only supply quality gaskets that match the OEM specification or even exceed it. We supply Ajusa, Glaser & Payen

pistons, liners & rings

Pistons, Liners & Rings

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Pistons, Liners & Rings

We have stock of a wide range of pistons and piston rings whether they are standard or oversized. We can supply Goetze, Nural, AE, Hastings, Tarabusi & NPR. Mahle, KS & Forged pistons are available by special request.

timing belts & chains

Timing Belts & Chains

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Timing Belts & Chains

Making sure your timing belt / chain and tensioners are replaced at the correct intervals is vital to the reliability of your motor. A cambelt / chain failure can be catastrophic to your engine. We have a good range of belts, belt kits, chains and chain kits on a same or next day basis.

valves, Guides & Seats

Valves & Guides

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Valves & Guides

We have a massive range of valves and guides on our shelves for European and Asian motors. Our stock is of the highest quality and is produced in Italy & Germany. Components are also available for vintage and classic cars by special request

Water & Oil Pumps

Oil & Water Pumps

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Oil & Water Pumps

We keep a good range of Oil Pumps & Dayco water pumps included with Timing belt kits. Water pumps can be arranged to order separately at special request.

Technical Support

If you can't find what you are looking for or would like any advice on what components you may need, our experienced sales staff are happy to help. We can provide technical information about parts and applications. We are dedicated to the engine parts sector and the majority of our team have been with us since we started in 1987.

Fast Delivery

We offer a same-day delivery service to exclusive areas of England on our internal van service. For areas outside our van delivery area, we offer a guaranteed next day delivery with either UPS, Parcelforce, DSV or DPD to ensure your car parts are delivered quickly. Please see our information page for more details


We only stock components from the World's leading brands. All of our parts have a minimum of 12 months of manufacturers warranty and are of OEM standard or higher. We have built our reputation over the years by selling good quality products at a very competitive price with fast and reliable delivery.

Our Brands

Our range of Engine Parts manufacturers from all over the World. These are the leading brands of engine components supplying the World's OEM &aftermarket sectors.

ACL bearings

Engine Bearings

ARP Bolts & Fasteners

Racing Spec Bolts, Nuts & Studs

AE bearings, Camshafts, Valves, Pistons & rings

Camshafts, Followers & Valvetrain

athena gaskets

Racing Head Gaskets

dayco timing belts / cam belts

Timing Belts & Kits

dayco timing belts / cam belts

Piston Rings

Freccia engine valves, guides, cam followers, rocker arms & hydraulic lifters

Valves, Guides, Rocker arms & Hydraulic Lifters

FP Diesel

Heavy Duty, Industrial & Commercial Engine Parts

Goetze Piston Rings

Piston rings

Glyco engine bearings

Engine Bearings

Glaser gaskets, seals & bolts

Gaskets, Seals & Bolts

Hastings piston rings

Piston Rings

king bearings

Engine Bearings

Nural Pistons

Pistons & Liners

Osvat engine valves, guides, shims & pre-combustion chambers

Valves, Guides, Shims & Pre-combustion chambers

Payen gaskets, seals & bolts

Gaskets, Seals & Bolts

Tarabusi pistons & rings

Pistons, Liners & Rings

Mahle Pistons & Valves

Valvetrain, Bearings & Pistons