Headgasket

[1fast93tsi]

Will a oem headgasket hold 30 psi of boost with head studs?

 

[kronus]

I know of a guy running right around 30 psi on a composite HG w/ L19's. A lot of people will tell you to upgrade to the ARP head studs vs. OEM head bolts, and that's pretty good advice if you're not running lots of boost.

If you are running lots of boost, you'll stretch those standard ARPs like a wet noodle. The general consensus is (in terms of tensile strength): 7-bolt head bolts<ARP standards<6-bolt head bolts<L19s or A1s.

When I finally crank up the boost next spring, I'm gonna move to L19s just be safe. Mod cheap, mod twice.

BTW, once you stretch the ARP's they're done. So you're looking at one time usage on those head studs.

 

[1fast93tsi]

Well, I'm thinking about getting a Mitsu MLS headgasket or cometic. I'm not sure which would be better. I'm gonna go with the ARP headstuds on this engine as it's stock block, with 272 intake and exhaust cams. Just a temp fix to run 30 psi while I'm building my other engine. On the new engine I will be going with the L19's. I plan on running 40 psi+ when I get it built.

 

[kronus]

Well, I'm thinking about getting a Mitsu MLS headgasket or cometic. I'm not sure which would be better. I'm gonna go with the ARP headstuds on this engine as it's stock block, with 272 intake and exhaust cams. Just a temp fix to run 30 psi while I'm building my other engine. On the new engine I will be going with the L19's. I plan on running 40 psi+ when I get it built.

A few things to note:

I've heard enough bad things about the Cometic to not use it on my car. I would only run three HG's on my car.

-OEM Composite (Stock head bolts of boost under 25psi, L19s or A1s for high boost applications.)
-OEM MLS (L19s or A1s and an O-ring)
-Felpro Permatorque MLS (L19s or A1s and an O-ring) Jake Montgomery uses this setup.

I repeat, I WOULD NOT WASTE MONEY ON THE ARPs. Especially if you plan on running 30psi. That will definitely be a temporary fix. 1 month, a week, a day, who knows, but I guarantee you'll lift that head and stretch those bolts and wish you had shelled out the money for the the higher grade studs.

 

[1fast93tsi]

Good point. I have also heard that cometic wasn't that good. Mitsu MLS will probably be the way I go. I'm still leaning towards just ARP headstuds as I don't daily drive this car so it wont see daily abuse or anything. I also may not run 30. I really havent decided yet. It all depends on how I'm able to tune it in.

 

[kronus]

Fair enough. Just be very careful on the ARPs. I definitely would not run anywhere near 30 on those, but that's just me. Let us know how things turn out.

 

[1fast93tsi]

Will do. I appreciate the info and help. I take forever to make decisions and I may change my mind again and decide to go with L19's. I don't know. I have ran 30 before on this engine with the stock head bolts and gasket when I raced a z06 vette. Wasnt really intentional though. The temp dropped a lot and the last I remember I was on was around 25 or 26 psi. Again I appreciate the help.

 

[TiradoCC]

You'll be more than fine with a Mitsu MLS headgasket and some ARP's. In my opinion L19's are a bit much for your goals......but if you have the money get the L19's.

 

[kronus]

Oh, and don't forget, you'll want both sealing surfaces to be VERY clean and smooth when running a MLS.

 

[Danny21]

Well what would a good head gasket be for my set up, i was just about to order a cometic mls head gasket then i read on this thread that people have herd problems with them. My set up will be a 6 bolt stock oem rebuild, bored .20 over, ported 2g manifold, megan o2 housing and downpipe with 2.5" exhaust,14b turbo, evo 550 injectors, and 2g maf sensor with k&n filter, pushing around 18lbs of boost and a 255lph walbro fuel pump. will the cometic mls head gasket be good for my setup?

 

[kronus]

You'll be just fine on an OEM composite. You could run standard ARPs too. I'm going to run an OEM composite w/ 6-bolt head bolts until spring when I get my head O-ringed and switch to L19s. Overkill for my setup right now (50trim etc) but I won't EVER have a problem w/ my HG after that.

 

[Danny21]

what is the difference between an oem head gasket and an oem composite head gasket.. also i have the money for a mitsu.. mls headgaskey off buschur would i just be better off with that?

 

[1_2befast]

For what you are doing, I would run the composite because it allows for a little inconsistency in the block and head surfaces. Plus you aren't pushing it hard enough to warrant using an MLS and worrying about getting it to seal.

 

[kronus]

what is the difference between an oem head gasket and an oem composite head gasket.. also i have the money for a mitsu.. mls headgaskey off buschur would i just be better off with that?

OEM is simply stuff you get from the manufacturer, like the dealer. What are your goals? Most people will be fine with an OEM composite. BTW, the Mitsu MLS is still an OEM gasket as well.

For what you are doing, I would run the composite because it allows for a little inconsistency in the block and head surfaces. Plus you aren't pushing it hard enough to warrant using an MLS and worrying about getting it to seal.

True, however with that much boost running through there, your method of holding the head to the block becomes paramount.

 

[fwdmaster]

Oem composite/arp studs

 

[JusMX141]

If you are running lots of boost, you'll stretch those standard ARPs like a wet noodle...

....I repeat, I WOULD NOT WASTE MONEY ON THE ARPs.

Haven't the standard ARP's been the best choice for many years? It just seems like since the newest hardened studs came out, everyone thinks the standard ARP's are garbage.

 

[dsm-onster]

Yes. They have been the standard for years. To add to the hype, since the 7bolt motors are now being pushed harderas well, suddenly ARPs arn't as good as 'my buddy's boyfriend with stock head bolts'. But everyone fails to mention that their aquantance uses a 6-bolt block. They also don't mention the resulting stretch measurement . The 6bolt head bolts are probably as strong as 7bolt ARPs. But 6bolt arp headbolts will hold down the head for a 500whp motor. It's not like it hasn't been proven.

BTW, Headbolts are rated at tensil strength not boost level. This means that engine torque (cylinder pressure) determines their limit not boost. 25psi from an evo3 16g is NOT 25psi from an hx40.

 

[JeffGST]

OEM Composite = Standard OEM HG. Soft material, metal fire ring
OEM MLS = Mitsubishi Multi layered METAL HG. Basically indestructable.

I use a Felpro Composite, standard ARP's and a O-ringed head in my Talon. This combo is good for 65lbs/min worth of airflow and 136MPH through the traps.

Reasons why I like the Composite HG

1) The HG is soft. The head and block deck don't have to be perfect for it to seal correctly. The soft material will take up any imperfections.

2) I like it because it CAN BE DESTROYED. I want my HG to blow if I have a fuel system malfuction or anything else that can possibly blow my motor. I rather blow my $35 HG then my 6-bolt block.

 

[dsm-onster]

Reasons why I like the Composite HG

1) The HG is soft. The head and block deck don't have to be perfect for it to seal correctly. The soft material will take up any imperfections.

2) I like it because it CAN BE DESTROYED. I want my HG to blow if I have a fuel system malfuction or anything else that can possibly blow my motor. I rather blow my $35 HG then my 6-bolt block.

Exact 2 reasons why I prefer this route as well. I'll likely never go over 140mph in the 1/4 mile. So that is all the gasket/studs I need. It makes it easy and free from complications to swap head gaskets. The 'knock fuse' is the best thing for an experimenter / home tuner. I blew my hg and cracked my piston ring lands at the same time. What would have happened if ALL the force from the knock had dumped onto my pistons? Bent rod or metal flying around in my crank case.

 

[1fast93tsi]

Yes. They have been the standard for years. To add to the hype, since the 7bolt motors are now being pushed harderas well, suddenly ARPs arn't as good as 'my buddy's boyfriend with stock head bolts'. But everyone fails to mention that their aquantance uses a 6-bolt block. They also don't mention the resulting stretch measurement . The 6bolt head bolts are probably as strong as 7bolt ARPs. But 6bolt arp headbolts will hold down the head for a 500whp motor. It's not like it hasn't been proven.

BTW, Headbolts are rated at tensil strength not boost level. This means that engine torque (cylinder pressure) determines their limit not boost. 25psi from an evo3 16g is NOT 25psi from an hx40.

I am on a Precision 6052. I have ran 30 psi on my stock headgasket with stock headbolts, but only twice. When I do this I will have my head milled, but not my block. Would this cause a problem with sealing correctly? My headgasket is not blown now, I just want to upgrade because I wanna try for 30 - 33psi possibly. Depending on how my tuning goes. Thanks for all the info so far.

 

[dsm-onster]

The beautiful thing about a composite gasket is that you don't have to worry very much about the surfaces. Just clean up the surfaces with a razorblade and bolt it down.

 

[talon14turbo]

Do you know if you can get the OEM composite gasket for the 2.4 g4cs block in .020 over (87mm)?

 

[z24frank]

Everything I read said mitsu MLS and ARPs so thats what I did.I know the L-19 are better but will you really need them?

 

[JeffGST]

Do you know if you can get the OEM composite gasket for the 2.4 g4cs block in .020 over (87mm)?

Lucky for you, Felpro designs their composite HG with an oversized bore.

Just purchase the Felpro Composite for the 4G63 and it is ready for a 87mm bore.

 

[1fast93tsi]

OEM Composite = Standard OEM HG. Soft material, metal fire ring
OEM MLS = Mitsubishi Multi layered METAL HG. Basically indestructable.

I use a Felpro Composite, standard ARP's and a O-ringed head in my Talon. This combo is good for 65lbs/min worth of airflow and 136MPH through the traps.

Reasons why I like the Composite HG

1) The HG is soft. The head and block deck don't have to be perfect for it to seal correctly. The soft material will take up any imperfections.

2) I like it because it CAN BE DESTROYED. I want my HG to blow if I have a fuel system malfuction or anything else that can possibly blow my motor. I rather blow my $35 HG then my 6-bolt block.

So, what would you think about non oringed head with composite gasket and arps? Since I'm not having the block resurfaced with the head, would the MLS not seal up properly? I'm not replacing because its blown or anything, just to assure it to hold. 60 trim turbo with around 30 - 33psi. Thanks.