Cometic MLS Base Gasket for Porsche 996 & 997.1 turbo Big Bore

What size are these?

The Cometic MLS Base Gasket for Porsche 996 & 997.1 turbo Big Bore are for 109mm spigots.  This is larger than the OEM size liner base, so these will fit 103.6 to 105mm liners that are machine fit and have 109mm bases.

• While these are available in 0.010″ thick like the oem base gasket on 996 turbo. we also offer 0.027″ thick like the oem base gasket on 997.1 turbo and even 0.040″ thick to lower compression, or give more room in a stroker engine.
• Our Base Gaskets will fit over big head stud kits.   7/16″, 12mm and even 1/2″ head studs.

Why shouldn’t I use OEM base gaskets?

• If you’re building your engine for high power you want to use the best base gaskets available. Cometic has made a tremendous name in racing and high powered street engines with their MLS base gaskets.
• If you’ve put in big head studs, you’ll be needing these.  OEM base gaskets are about impossible to drill out and oversize, therefore you’ll save shop time and excessive labor by purchasing the correct base gaskets for your build.
• If you’ve installed big bore pistons with machine fit liners you’ll need these as well!

Can I use these on a stock engine without big head studs?

Eh…  in a pinch you could, but you’re better off using the correct gasket.

how many do I need?

You’ll need a quantity of 2 for a full build while 1 is adequate for a single bank repair.

What is MLS?

MLS stands for Multi-Layer Stainless steel gaskets.  A type of gasket commonly used in high performance applications.  The exterior of the gaskets are coated for a perfect seal.  The important sealing areas are embossed for higher pressure and improved sealing.

Need help with your build?

Check out Protomotive Engine building and Protomotive consulting service.