Many users and tuning shops encouraged us to start selling metal head gaskets, including for B6 standard (STD) bores and tempered metal head gaskets for turbo cars: B6 and BP lines.
We used to use 81.0mm diameter bores for STD pistons (78.0mm-81.0mm).
However, many users do not require compression down, and their requests are enough to change our bore diameters.
The improved bore diameter is 79.0mm, even though the STD cylinder bore is 78.0mm.
The reason why we have opted for 79.0mm is that the diameter ranges of the genuine pistons for O/H gaskets are up to 78.5mm.
The genuine head gasket, made with asbestos, actually has a 79.5mm bore diameter and a 1.3mm thickness, while our metal head gaskets have a more user-friendly spec than the genuine ones that are not good for tunings.
Maruha Metal Head Gaskets for B6 Lines
| Bore Diameter | Thickness | Gasket Type |
| 79.0mm | 0.8mm | Bead Type |
| 79.0mm | 1.0mm | Bead Type |
| 79.0mm | 2.0mm | Stopper Type (for B6 turbo) |
| 81.0mm | 0.8mm | Bead Type |
| 81.0mm | 1.0mm | Bead Type |
We emphasize that the bore thickness of the stopper types is 2.0mm.
This allows supercharger and turbocharger gaskets to be a superior stopper.
The stopper type gaskets can control compression ratios precisely and can prevent dropping gaskets caused by severe boost pressures.
Maruha Metal Gaskets for BP Lines
| Bore Diameter | Thickness | Gasket Type |
| 83.0mm | 2.0mm | Stopper Type (for BP turbo) |
| 86.0mm | 0.6mm | Bead Type |
| 86.0mm | 0.8mm | Bead Type |
| 86.0mm | 2.0mm | Stopper Type (for BP turbo) |
The list shows you that we have bead types and stopper types for Maruha
Head Gasket Lines.
Now, let us talk about the differences between the 2 types.
(Picture) stainless steel bead
Left: Maruha Metal Head Gasket (for BP of 86.0mm lines)
Keeping the sealing property by sandwiching a bead.
Right: The Genuine NA8 Head Gasket
Compared to Maruhafs gasket, it seems that there is no bead.
But in fact, a method to form a cored plate into a bead is being used.
Down: The Genuine B6 Head Gasket
Grommet type gaskets with carbon seats are adopted.
The bores are more than 79.5mm, which may suggest that they are not useful for tunings by judging their performance and compression.
The stopper is set on the single side of the gasket, which is different from grommet types.
And the other side is flat to increase sealing by fitting the bead gasket to stainless steel.
Metal head gaskets are all-purpose gaskets used as genuine parts as well as tuning parts.
They used to be pricey, but they became popular because their mass production can contribute to stable price levels and can prevent asbestos gaskets from causing air pollution and health damage.
The great point of metal head gaskets is the metalfs high conduction that avoids heat accumulation.
It conducts heat within the combustion chamber to the block side smoothly and the gasket blowing caused by heat fusion can be reduced.
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