Multi Layer Steel Head Gaskets (MLS)
We get a lot of curiosity and questions from customers about the use of a multilayer steel head gasket...
At VAC we have found the MLS Gaskets to be much more durable than older style OEM gaskets and have had great success with them in all the engines that we have installed them in be it Race, Street, N/A and especially Forced-Induction.
MLS gasket technology is a proven winner in countless scenarios and its success is based on proper care and procedure when installing. Rumors spread when MLS gaskets were first introduced in the aftermarket are just that: rumors. MLS is good enough for many of the new, state of the art engines today including those from BMW. With proper installation MLS gaskets consistently out perform other gasket types.
The flexibility of a standard type head gasket allows for 'gross imperfections' in the mating surfaces during assembly, but this is exactly why it can fail under high performance use. When using the multilayered steel head gasket it is important to note that these gaskets are more rigid than standard gaskets and therefore the head and block need to be flat & clean,preferably resurfaced, to maintain a correct and quality install that prevents leaks better than a standard gasket.
Leaks, Problems, Copper spray?
MLS head gaskets go on dry because they are coated with a sealant. Each MLS head gasket is coated with a .001" thick viton rubber that is bonded to the outer stainless steel layers. Adding an additional sealer can hinder the performance of an MLS head gasket. Typically when people complain about their MLS gasket weeping, either:
The surface finish is not up to spec (50 RA or better).
They did not have the timing cover bolted to the block when it was resurfaced, or...
They did not put a dab of sealant where the timing cover meets the block.
It is important to note that if your block has been resurfaced then it is vital that the timing cover be resurfaced with the block otherwise leaks may occur. Do things properly and you will be rewarded with great success... We have built many engines with MLS gaskets and we do not use a copper spray.
How to Install:
When applying torque to the head stud nuts or OEM bolts always use a torque wrench!
We highly recommend using our head stud kits as these provide a much better method of fastening. We have the highest quality ARP and Racetech head studs available for all BMW models and suggest you use them as they offer the most reliable seal with the MLS gasket.
1. Make sure that the surfaces on the gasket, block and head are clean and dry. (We strongly recommend having a qualified machine shop test and resurface the head. This is what all professional engine builders do.)
2. Place the head gasket on the block making sure it is aligned correctly and that it is the correct gasket and bore size for your application.
3. Place a small bead of gasket sealant on the top and bottom part of the gasket around the timing chain cover area.
4. Then carefully place the head on top of the gasket.
5. If using the factory bolts follow the factory instructions. Always torque the bolts in the correct BMW order. Again we highly recommend a VAC head stud kit with the MLS gaskets.
6. If using the (ARP) Head Stud, USE ONLY ARP's Moly lube to the head studs and thread through the cylinder head and into the block until hand tight. Find ARP's specs by clicking here
7. Place the washers onto the studs. Apply Moly lube to top of studs.
8. Thread the nuts onto the studs until finger tight.
9. Torque the nuts in the correct sequence to approximately 1/3rd of the final torque value. (Be mindful: In the case of ARP, of their torque specifications. BMW OE specs are commonly a different value)
10. Repeat step 9.
11. Torque the nuts in the correct BMW sequence to approximately 2/3rds of the final torque value.
12. Repeat step 11.
13. Torque the nuts in the correct BMW sequence to the final torque value
14. Wait for approximately 1/2 hour minimum, the longer the wait the better the result.
15. Re-torque the nuts in the correct BMW sequence again to the final torque value of the respective hardware manufacturer.
If for any reason you have difficulty understanding these instructions please call us!