Which HG??

[Miasma]

Hey, I'm just wondering which head gasket some of you would recommend for my engine.

My build consists of:

2.4 Long Rod 4g64
OEM Crank Shaft
Manley 156mm H Plus Rods
Manley Pistons 9.1:1
ARP Head & Main Studs
ACL Race Main & Rod Bearings

EVO 8 Cylinder Head
OEM Valves, Guides, Rockers, and Lifters
Cosworth Single Springs
Cosworth M2 Camshafts 272/272

HX40 twin scroll

I will be running 30+ psi

 

[WES_393]

If you already have the engine torn down, then you might consider getting the head and deck resurfaced for a MLS head gasket. I would suggest the OE MLS gasket over something like Cometic. Just be sure to let the machinist know your going to be using an MLS gasket and want the surface finish to be at least 50 RA.

However, the option of a Composite gasket is still open. The upsides are price, ease of install, and the idea that a composite gasket will blow out under extreme pressure and potentially save the engine. The downside is that they won't put up with knock/detonation so proper tuning is a must at high power.

 

[Boostdriven]

Like WES said, I would choose OE MLS over Cometic but either one would work. Currently I run OE MLS on my car with L19s torqued to 120. May be 120 is a bit much but I thought just in case I don't know what others do but I like to use a little bit of copper spray on both sides of the head gasket, it has never failed me. The only time that I didn't use copper spray I blew some top brand $200 dollar head gasket that I bought from slowboyracing. Since then I installed OE MLS and it works to this day, daily driven and holds 40 psi on HX52.

I've used a Cometic gasket on my brother's car with factory surfaces on both head and block. After cleaning up both surfaces I checked them for straightness, the block was 100% straight but the head had a slight crown in it. It would touch the block on the outside but the center had a slight gap, maybe .003-.005 thousands. So I installed a head stud in the center and tried to tighten it down to see what it will do. With very little effort of a wrench it tightened down and sat perfect. So some copper spray and regular ARPs torqued to 105 and a car is still on the road. This was about a yeah and half ago, car is daily driven running 30 psi on HX35.

Some people have great success with composite gaskets but they are less forgiving. Allot of it will depend on tuning, so if you know what you're doing on the laptop then I wouldn't use a composite gasket, I would use MLS instead.

 

[bastarddsm]

#### MLS. The head moves around on the block and abrades the gasket. Have a surface with a low Ra, and run a felpro composite gasket.

I'm making enough power to push a 3400lb car 137 in the 1/4, and I run a felpro composite ($35) and standard ARP's. No leakage at all. I finish my block and head with 320 grit paper by hand. I torque to 90 ft*lbs with ARP lube. It is a 6 bolt with 12mm studs.

It has enough "give" to "pop" before a ####ed tune hurts the shortblock.