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Westwood
Westwood for Porsche
The company originally started as Westwood Trading over 19 years ago, and then merged with its sister company, to form Westwood Cylinder Liners Ltd. Duncan Andrews and his late father Paul Andrews have over 40 years experience in the engine remanufacturing industry. Our family have been involved with the rebuilding of engines since the 1930’s. Duncan Andrews Great Grandfather, Billy Andrews started an engine rebuilding company after the First World War. Our customers include leading Porsche engine reconditioners and rebuilders and race engine builders.
Choosing the Right Fit for Your Porsche
Where Westwood is listed for Porsche, use the supplied model coverage and OE references to confirm suitability. Check details that commonly affect fitment such as model year, side/position, and connector type where relevant.
- Typical reasons people replace these parts include completing scheduled maintenance properly, resolving internal wear, and refreshing related components during an engine rebuild so the engine remains dependable.
- Common symptoms that may lead to replacement are misfit parts, premature wear, poor sealing, and repeat issues after repair when the wrong variant is used or related consumables (seals, fixings, gaskets) are not renewed.
- Before ordering, match your Porsche model and year carefully, and cross-check any part numbers or technical notes supplied.
- Where possible, confirm the underlying fault with tests and inspection so you are replacing the correct components, not just symptoms.
Browse by Category
If you already know the area you are working on, start with the category and then filter by Porsche model. Where real-world symptoms and typical reasons to replace are provided, use them to keep the wording grounded.
Engine Rebuild Parts — Engine rebuild parts are typically chosen when a Porsche engine shows internal wear or damage, or as part of a planned overhaul where gaskets, seals, bearings, chains, and hardware are renewed while the engine is apart to restore reliability and performance.
- Confirm the need for a rebuild with compression and leak-down tests, oil/filter inspection, and bore checks before committing to major parts spend.
- When planning a rebuild, consider replacing chains, guides, seals, and hard-to-access wear items at the same time to avoid repeat labour.
Engine Bearings / Shells — Bearings and shells are renewed to restore correct oil clearances and protect the crankshaft and rods, especially after low oil pressure events, high mileage, or contamination where wear patterns are visible on teardown.
- Low oil pressure, rumbling noises under load, or metallic debris in the oil are strong prompts to inspect and, if necessary, replace bearings.
- Always measure clearances, inspect crank journals, and address root causes such as oil starvation or overheating during bearing work.
Piston Rings — Piston rings are replaced when wear causes low compression, blow-by, and increased oil consumption, often as part of a top-end or full rebuild to re-establish proper sealing between piston and cylinder.
- Use compression and leak-down testing, plus observation of smoke behaviour, to distinguish ring issues from valve guide or seal problems.
- Plan for cylinder inspection and appropriate honing or machining when fitting new rings so they can bed in and seal correctly.
Engine Cylinders / Liners / Pistons — Cylinders, liners, and pistons are changed when scoring, ovality, or damage prevents reliable sealing, or when upgrading displacement and strength for higher-output Porsche builds.
- Scoring found on inspection, persistent low compression, or oil consumption that does not trace to external leaks often indicates the need for cylinder and piston work.
- Always treat pistons, rings, and cylinder surfaces as a matched system, checking clearances, materials, and coatings as a set.
Cylinder Head / Camshaft Carrier — Cylinder heads and camshaft carriers are addressed when there are oil leaks, valve guide wear, top-end noise, or overheating-related distortion, and are a key part of restoring compression and oil control on many Porsche engines.
- Smoking on overrun, oil around cam covers, or rough idle with low compression can all point towards top-end inspection and potential head work.
- During head and cam carrier work, plan for new gaskets and seals and follow any recommended checks on timing components and cooling systems.
Explore Westwood at Design911
View the current Westwood range for Porsche at Design911, then filter by model and category to narrow down to the right parts.
- Porsche Boxster 981 S / GTS 3.4L 2012-16
- Porsche 991.1 Carrera C2 3.4L (350 Bhp) 2012-16
- Porsche 991.1 Carrera C4 3.4L (350 Bhp) 2012-16
- Porsche Cayman S / GTS 3.4L 981 2013-16
Engine 3.4L, 97.00mm Bore, Ductile Iron flanged liners (With Hole and cutouts machined)
Fits:
Porsche 991 3.4L Engine Only Price SET OF 6
Porsche 981 3.4L Engine Only Price SET OF 6
NEW Ductile Iron cylinder liners suitable for repairing damaged Alusil bores in 991 / 981 engines.
These New Ductile liners now have the cutouts and gudgeon pin hole already pre machined into the liners. The liners will only need to be bored and honed after fitment.
These liners are becoming very popular, with increasing numbers of cars suffering from scoring in the bores.
The liners will need to be fitted by a professional machine shop. You will not need to get special pistons or rings, as the original spec ones can be used with these Ductile liners.
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
6 sets per engine. Price is for 1 set.

Fits:
Porsche 996 3.6L 002>>
M96.03 Engine ø96 mm, Ringe 1,20 x 1,50 x 2,00mm
997 3.6L M96.05
These piston rings are suitable for original Locasil bores and our own Cast Iron / Ductile cylinder liners. These are manufactured to the Original OE Specification, so will fit OE Pistons.
Click 'Zoom in' for large parts diagram.
Diagram Ref No 2.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610305304
The product you are viewing cross references to these numbers
- Porsche 997 MKII Carrera C2S 3.8L 2009-12
- Porsche 997 MKII Carrera C4S 3.8L 2009-12
- Porsche 997 MKII Turbo 2010-13
- Porsche 991.1 Carrera C2S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Carrera C4S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Turbo 3.8L (520 Bhp) 2014-16
- Porsche 991.1 Turbo S 3.8L (560 Bhp) 2014-16
- Porsche Cayman GT4 3.8L 2015-16
6 sets per engine. Price is for 1 set.
Fits:
Porsche 997.2 3.8L 2009-2012 MA1.01 Engines
Porsche 997.2 Turbo 3.8L 2009-2012 MA1.70 Engines
Porsche 991 3.8L Carrera S MA1.03 Engines
Porsche 991 Turbo 3.8L
Porsche 987C Cayman GT4 2016
ø97 mm,
Click 'Zoom in' for large parts diagram.
Diagram Ref No 2.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
9A110307502
The product you are viewing cross references to these numbers
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
Cut outs and circlip insertion tool holes need to be machined after fitting. Ductile Iron Material.
Fits:
Porsche 997 3.8L Price is Each
Inside Diameter 99.00mm / 3.898inch
Outside Diameter 104.20mm / 4.102inch
Length 128.00mm / 5.040inch
Flange Diameter 113.50mm / 4.469inch
Flange Depth 46.00mm / 1.811inch
The liners will need to be fitted by a professional machine shop. You will not need to get special pistons or rings, as the original spec ones can't be used with these cast iron liners.
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche Boxster S 987 MKII 3.4L 2009-12
- Porsche Cayman S 3.4L 987C 2005-08
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
Note:
This liner has the Insertion Tool hole already machined. Suitable for Cylinder 6. Standard Spun Cast Material.
Fits:
Porsche Cayman 3.4L Price is Each
Porsche Boxster 3.4L Price is Each
Inside Diameter 96.00mm / 3.779inch
Outside Diameter 101.20mm / 3.984inch
Length 128.00mm / 5.040inch
Flange Diameter 106.65mm / 4.199inch
Flange Depth 5.00mm / 0.197inch
The liners will need to be fitted by a professional machine shop.
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche Boxster S 987 MKII 3.4L 2009-12
- Porsche Cayman S 3.4L 987C 2005-08
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
Note:
This liner has the Insertion Tool holes already machined. Suitable for Cylinders 4 & 5. Standard Spun Cast Material.
Fits:
Porsche Cayman 3.4L Price is Each
Porsche Boxster 3.4L Price is Each
Inside Diameter 96.00mm / 3.779inch
Outside Diameter 101.20mm / 3.984inch
Length 128.00mm / 5.040inch
Flange Diameter 106.65mm / 4.199inch
Flange Depth 5.00mm / 0.197inch
The liners will need to be fitted by a professional machine shop.
- Porsche 944 2.5L 8V 1982-87
- Porsche 944S 2.5L 16V 1987-88
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 944 Turbo 2.5L 8V 1985-88
- Porsche 944 Turbo 2.5L 8V 1989-91
- Porsche 944 Turbo S 2.5L 8V 1988
Price is for each cylinder. Four pieces required for complete engine set.
Wet Type liner, with semi finished bore for final finishing after fitting.
Fits:
Porsche 944 2.5L / 3.0L - 4 Cyl Engine
Please note: If you require a different size liner, please send us an enquiry.
- Porsche 944 2.5L 8V 1982-87
- Porsche 944S 2.5L 16V 1987-88
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 944 Turbo 2.5L 8V 1985-88
- Porsche 944 Turbo 2.5L 8V 1989-91
- Porsche 944 Turbo S 2.5L 8V 1988
Price is for each cylinder. Two pieces required for complete engine set.
2 x L2817
2 X L2823
Wet Type liner, with semi finished bore for final finishing after fitting, 2 flats on flange.
Fits:
Porsche 944 2.5L / 3.0L - 4 Cyl Engine
Please note: If you require a different size liner, please send us an enquiry.
- Porsche 944 2.5L 8V 1982-87
- Porsche 944S 2.5L 16V 1987-88
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 944 Turbo 2.5L 8V 1985-88
- Porsche 944 Turbo 2.5L 8V 1989-91
- Porsche 944 Turbo S 2.5L 8V 1988
Price is for each cylinder. Two pieces required for complete engine set.
2 x L2817
2 X L2823
Wet Type liner, with semi finished bore for final finishing after fitting, 1 flat on flange.
Fits:
Porsche 944 2.5L / 3.0L - 4 Cyl Engine
Please note: If you require a different size liner, please send us an enquiry.
- Porsche 997 MKII Carrera C2S 3.8L 2009-12
- Porsche 997 MKII Carrera C4S 3.8L 2009-12
- Porsche 991.1 Carrera C2S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Carrera C4S / GTS 3.8L (400/430 Bhp) 2012-16
Engine 3.8L, 102.00mm Bore, Ductile Iron flanged liners (With Hole and cutouts machined)
Fits:
Porsche 991 3.8L MA1 Engine Only Price SET OF 6
Porsche 997.2 3.8L MA1 Engine Only Price SET OF 6
NEW Ductile Iron cylinder liners suitable for repairing damaged Alusil bores in 991 engines.
These New Ductile liners now have the cutouts and gudgeon pin hole already pre machined into the liners. The liners will only need to be bored and honed after fitment.
These liners are becoming very popular, with increasing numbers of cars suffering from scoring in the bores.
The liners will need to be fitted by a professional machine shop. You will not need to get special pistons or rings, as the original spec ones can be used with these Ductile liners.
- Porsche 955 Cayenne S 4.5L V8 2003-06
Semi Finished bore 92.50mm
(Less 1.00mm for final finishing in bore)
Fits:
Porsche Cayenne V8
These liners are becoming very popular, with increasing numbers of cars suffering from scoring in the bores.
The liners will need to be fitted by a professional machine shop. You will not need to get special pistons or rings, as the original spec ones can be used with these cast iron liners.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
948100901XX
The product you are viewing cross references to these numbers
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche Boxster S 987 MKII 3.4L 2009-12
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche Cayman S 3.4L 987C 2005-08
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
- Finish Bore Size: 96.00mm Less 0.50
- Outside Diameter: 101.20mm
- Overall Length: 127.75mm
- Flange Diameter: 110.50mm
- Flange Depth: 45.21mm
Fits:
Porsche 996 3.4L Price is Each
Porsche 996 3.6L Price is Each
Porsche 997 3.6L Price is Each
Porsche Cayman 3.4L Price is Each
Porsche Boxster 3.4L Price is Each
NEW Cast Iron cylinder liner suitable for repairing damaged Alusil bores in 996 / Cayman 3.4 / 3.6 engines, especially with "D" Chunk Damage
The liners will need to be fitted by a professional machine shop. You will not need to get special pistons or rings, as the original spec ones can be used with these cast iron liners.
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche Boxster S 987 MKII 3.4L 2009-12
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche Cayman S 3.4L 987C 2005-08
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
Fits:
Porsche 996 3.4L Price is Each
Porsche 996 3.6L Price is Each
Porsche 997 3.6L Price is Each
Porsche Cayman 3.4L Price is Each
Porsche Boxster 3.4L Price is Each
Inside Diameter 96.00mm / 3.779inch
Outside Diameter 101.20mm / 3.984inch
Length 128.00mm / 5.039inch
Flange Diameter 106.65mm / 4.199inch
Flange Depth 5.00mm / 0.197inch
NEW Cast Iron cylinder liners suitable for repairing damaged Alusil bores in 996 engines.
These liners are becoming very popular, with increasing numbers of cars suffering from scoring in the bores.
The liners will need to be fitted by a professional machine shop. You will not need to get special pistons or rings, as the original spec ones can be used with these cast iron liners.
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
Engine 3.6L, 96.00mm Bore, Ductile Iron flanged liners (With Hole and cutouts machined)
Fits:
Porsche 996 3.6L Price SET OF 6
Porsche 997 3.6L Price SET OF 6
Inside Diameter 96.00MM / 3.779inch
NEW Ductile Iron cylinder liners suitable for repairing damaged Alusil bores in 996 engines.
These New Ductile liners now have the cutouts and gudgeon pin hole already pre machined into the liners. The liners will only need to be bored and honed after fitment.
These liners are becoming very popular, with increasing numbers of cars suffering from scoring in the bores.
The liners will need to be fitted by a professional machine shop. You will not need to get special pistons or rings, as the original spec ones can be used with these Ductile liners.
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
Engine 3.8L, 99.00mm Bore, Ductile Iron flanged liners (With Hole and cutouts machined).
Fits:
Porsche 997 3.8L Price SET OF 6
Inside Diameter 99.00mm / 3.898inch
NEW Ductile Iron cylinder liners suitable for repairing damaged Alusil bores in 997 engines.
These New Ductile liners now have the cutouts and gudgeon pin hole already pre machined into the liners. The liners will only need to be bored and honed after fitment.
These liners are becoming very popular, with increasing numbers of cars suffering from scoring in the bores.
The liners will need to be fitted by a professional machine shop. You will not need to get special pistons or rings, as the original spec ones can be used with these Ductile liners.