LS Head gaskets for boost

Looney Duner

Looney Duner

Well-known member
Joined
May 9, 2021
Messages
620
Reaction score
513
Finally getting around to building my engine. Ls2, with a blower. Looking at head gasket options, and there is a ton to choose from. So what are you guys running with success? This is my first LS build, so I'm learning as I go. I have built many engines over the years, but never one of these.....
 
Buddy just went through an issue. Had a blown head gasket from the engine builder.
After doing some research into what the motor was built with and what is preferred with boost, he went with Cometic, 5 layer gasket. The gaskets that the motor came with were only 3 layer.

Also, make sure you are using all ARP stuff. ARP 234-4345 is what he put into his LS2.
 
LS9 gaskets from GM Performance or Cometic Multi Layer Steel. You can choose the thickness of the Cometic to help with CR.
 
So looking at cometic website, the MLX series are 5 layer, and are built slightly differently then the standard MLS, better for boost. The closest bore size they have to my engine is 4.060 and my bore is 4.010. Anyone see a problem with that?
Also, I like that I can get it in various thickness to lower my comp. Just a little more, I believe I'm at 9.3:1 with a .053 gasket, I'd like to go with .075 to drop it a hair more and be a little more comfortable. Any downside to going with a thicker gasket?
Thanks for the help so far
 
How much boost are you trying to run? For me with a dune car I’d keep my compression at 10.5:1. Especially if you’re not running 20lbs. No need to gut the motor down low to only pick up where you’re gonna have to shift anyways.
 
I agree with Jtmoney. Both of my boosted motors have been built at 10:1 compression. On purpose since I knew I wasn’t going to run crazy boost.

That being said.
That bore size will be fine.
I would for sure get the MLX gaskets.
 
Ok, sounds like I will be leaving it at 9.3:1. The bottom end is already assembled, so no going back now. I'll go with the MLX gasket in a normal thickness.
 
I set the comp low cause it's a pump gas motor, the pulley on the blower should be around 10 psi. We will see how it goes. May have to go lower, or switch to race gas or possibly meth injection. Built a vw back in the day, with 14 psi, on pump gas, with a heavy dose of meth injection, but it was 8.5 comp ratio.... where I used to work we did a ton of turbo engines, (NOT VW) and those ran on pump up to 14 psi or so, again with low comp ratio. Around 9.5 or less, if I remember correctly. But that was 20+ years ago. Admittedly, this is my first time fooling around with a blower... I'm excited to see how it plays out
 
Modern engines are pretty damned detonation resistant under boost. Healthy quench, better head cooling, engine management, etc.
 
You must log in or register to reply here.
Back
Top