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3.0L 24v - S58B30
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3.0L 24v - S58B30
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Reinforced Athena and Cometic head gaskets, in O-Ring, MLX and DST. Sold individually, one gasket per engine.
The BMW S58B30 is the 3.0 litre twin-turbo inline-six petrol engine fitted to the BMW M2, M3, M4, X3 M and X4 M. Its bore is 84 mm with a 90 mm stroke.
This original gasket carries the part number 11 12 8 088 729. BMW lists it as a cylinder head gasket without stating its construction, with a thickness of 0.95 mm. The engine takes only one. It is rated for the original combustion pressure: as that pressure rises, clamping load fades, the cylinder head lifts and coolant passes into a cylinder.
A head gasket does not make the seal by itself: it holds because the fasteners press the head onto the block. A composite gasket ends up crushed for good beyond 100 N/mm² of admissible stress, whereas the 301 stainless steel of MLX gaskets withstands 517 N/mm², 5 times more, and regains its shape at every combustion. The O-Ring shares the roles differently: its stainless ring alone seals the combustion, the body handles the water and oil circuits, and nothing has to be machined in the block.
This page brings together the part numbers of two racing manufacturers, Athena and Cometic, in three constructions: O-Ring with a stainless ring, MLX with a chamber stopper and DST with a double stopper. Every gasket has an 85 mm bore, larger than the engine's 84 mm bore, and thicknesses run from 0.91 to 1.80 mm enough to adjust the compression ratio without touching the pistons or the cylinder head. As a rule, the gasket bore chosen is at least 0.5 mm larger than the actual cylinder bore. Each part number is sold individually, one gasket per engine.
| Gasket bore | Thickness OEM 0.95 mm | Gasket volume | Gasket type OEM not specified | Brand | Part number OEM 11 12 8 088 729 |
| 85 mm | 0.91 mm | 5.16 | MLX | Cometic | C15696-036 |
| 85 mm | 1.00 mm | 5.67 | O-Ring | Athena | 330213R |
| 85 mm | 1.40 mm | 7.94 | MLX | Cometic | C15696-055 |
| 85 mm | 1.60 mm | 9.08 | DST | Cometic | C14207-063 |
| 85 mm | 1.80 mm | 10.21 | DST | Cometic | C14207-071 |
Gasket volume is the free space left above each cylinder. It adds to the combustion chamber: the larger it is, the lower the compression ratio falls. Compare it only between gaskets of the same bore.
| Fasteners | Engines | Tightening torque |
| Original cylinder head bolts 11 12 8 644 675, M11 x 188 | S58B30 | As per the manufacturer's documentation |
Before fitting, check the flatness of the head and the block with a straight edge, and have them machined if needed. None of these gaskets requires sealant: Athena and Cometic both deliver them already treated.
| Cometic DST A stack of seven stainless steel layers: two integrated, precision-folded stopper layers combined with embossed sealing layers that carry Cometic's proprietary coating. The clamping force is spread evenly across the cylinder head and the block, which markedly reduces bore distortion and makes the seal more reliable. The DST is a direct bolt-on solution: no extra machining of the head, no grooving and no o-ringing, as is usually required in extreme forced induction. It carries on from Cometic's MLX stopper design. | |
 | Cometic MLX A multi-layer stainless steel stack whose centre layer, precisely folded, forms a stopper around the combustion chamber. The embossed outer layers isolate the oil and coolant passages. Local clamping increases without adding bore distortion. To choose when boost calls for a stronger all-steel gasket, in 85 mm only. |
 | Athena O-Ring / Cut Ring A steel plate coated with asbestos-free aramid fibre, with a stainless steel compression ring around each cylinder. The ring concentrates the clamping on a reduced diameter, where the seal is won or lost, and a silicone bead protects the water and oil passages. It is the construction that withstands the highest pressures, and the only one that suits a head already prepared with a compression wire. |
Gasket bore. The Athena O-Ring, the Cometic MLX and the Cometic DST all come in 85 mm, and in that bore only.
Thickness. The original gasket is 0.95 mm thick. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.
| Your goal | Thickness to choose |
| Keep the original compression ratio | 0.91 mm or 1.00 mm, the two values closest to the original 0.95 mm |
| Skimmed cylinder head, make up the lost height | 0.91 mm or 1.00 mm + what was removed |
| Forced induction build, lower the ratio | A thickness above 1.00 mm |
| Naturally aspirated build, raise the ratio | 0.91 mm, the thinnest offered: no thinner option exists on this page |
With the 0.91 mm, thinner than the original gasket, measure with a dial gauge how far your pistons stand above the block: it sets the clearance left between piston and head.
 | Athena S.p.A. is an Italian maker of engine gaskets and components; its head office and main plant are in Alonte, in Veneto. The group also manufactures in Spain, the United States, Brazil and India. Its multi-layer gaskets equip car manufacturers as original equipment, and its racing range is entirely designed and made in Italy. |
 | Cometic Gasket, Inc. was born in 1989 in Concord, Ohio: this American manufacturer designs gaskets and sealing solutions for engines. Its speciality is the gasket made to order, in the bore and thickness wanted. All its production stays in the United States, using American materials. |
| Criterion | Original gasket 11 12 8 088 729 | Reinforced gaskets |
| Construction | Construction not stated by the manufacturer | Multi-layer stainless steel, or steel and aramid fibre with a stainless ring |
| Gasket bore | Not stated | 85 mm |
| Thicknesses available | 0.95 mm | 0.91 to 1.80 mm, 5 values |
| Compression ratio adjustment | None | Through the thickness chosen |
| Resistance to overpressure | Limited to standard output | Designed for forced induction |
| Model | Engine code | Power | Years |
| M2, M2 CS, M2 xDrive (G42, G87) | S58B30 | 460, 480 and 530 hp | 2022- |
| M3, M3 Competition, M3 Competition xDrive, M3 CS xDrive (G20, G80, G28) | S58B30 | 480, 510, 530 and 551 hp | 2020- |
| M3 Touring Competition xDrive, M3 Touring CS xDrive (G21, G81) | S58B30 | 510, 530 and 551 hp | 2022- |
| M4 Coupé, M4 Competition, M4 Competition M xDrive, M4 CS xDrive, M4 CSL, 3.0 CSL (G22, G82) | S58B30 | 480, 510, 530, 551 and 560 hp | 2020- |
| M4 Cabriolet Competition M xDrive (G23, G83) | S58B30 | 510 and 530 hp | 2021- |
| X3 M, X3 M Competition (G01, F97, G08) | S58B30 | 480 and 510 hp | 2019- |
| X4 M, X4 M Competition (G02, F98) | S58B30 | 480 and 510 hp | 2019- |
OEM part number: 11 12 8 088 729.
Important: the part numbers on this page fit only the S58B30: check your vehicle's engine code before ordering.
The reinforced gasket keeps its shape instead of being crushed when combustion pressure exceeds what the original gasket can hold.
When power climbs, through a turbo, a supercharger or a raised compression ratio, the head gasket is the first link to fail in the top end. Choosing a reinforced one is therefore a matter of reliability rather than comfort: it avoids the breakdown and the head removal that comes with it.
