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Headgasket for 35-40psi??

camfast

Proven Member
432
22
Jun 6, 2008
Houston, Texas
I just got my cylinder head redone from the machine shop and I also have ARP head studs. Which headgasket would work best if i want to eventually run 30-40 psi?? I was thinking a Mitsu mls headgasket?? Any suggestion is appreciated. thanks
 

johnboy1065

Proven Member
117
0
May 26, 2009
kingsport, Tennessee
I'd say go with the mitsubishi multi-layer metal head gasket and some ARP headstuds...
 

2slow4utsi

Proven Member
659
6
Mar 7, 2009
Eastpointe, Michigan
You don't need L19s. I think those are overkill even for 35 psi. Correct me if I'm wrong.
 

camfast

Proven Member
432
22
Jun 6, 2008
Houston, Texas
I have the regular 12mm ARP head bolts. Will these bolts even have a chance at 35 psi? If i have to then i will have to buy the L19's.
 

OneBad2L

Proven Member
145
3
May 20, 2009
Saranac, New_York
If the stock setup can hold down 28-30psi, I don't see the regular ARPs with a Felpro or Mitsu MLS not being able to hold 35-40. They may stretch after a good bit of use, but they will hold and should last awhile.
 

JayRolla

Proven Member
5,632
31
Feb 23, 2006
Colorado Spring, Colorado
I like to upgrade once and thats it. I would get the L19's for good measure if I had a 7 bolt. Im still using the stock 6 bolt head studs that where made in 1991 on two heads and I run 32psi spikes daily.
 

dsmfa9nutter

Proven Member
1,025
4
May 9, 2005
Nowhere, Wisconsin
What are you building that's going to run 40psi?? If you are not another noob idiot that wants to run huge boost because he thinks it's cool, then you'd be best off with a mls and l19's. If you are a noob idiot, you don't need to run 40psi to make power.
 

camfast

Proven Member
432
22
Jun 6, 2008
Houston, Texas
What are you building that's going to run 40psi?? If you are not another noob idiot that wants to run huge boost because he thinks it's cool, then you'd be best off with a mls and l19's. If you are a noob idiot, you don't need to run 40psi to make power.


Right now i have an 18g that was running on 20 psi but in the near future i will be changing to a HX-40 setup. I think that 30-40 psi is where i would want to run this turbo with e-85. So my question is would my current ARP stud along with a Felpro mls headgasket hold up to the 30-40psi? or do i absolutely need to change to L19's?
 

99gst_racer

Moderator
11,797
979
Apr 5, 2003
Coloma, Michigan
really stock hg and studs for 28-30lbs?

It worked well for me, but I wouldn't have guessed it would have otherwise.

Right now i have an 18g that was running on 20 psi but in the near future i will be changing to a HX-40 setup. I think that 30-40 psi is where i would want to run this turbo with e-85. So my question is would my current ARP stud along with a Felpro mls headgasket hold up to the 30-40psi? or do i absolutely need to change to L19's?

I agree that the Felpro MLS is probably your best option. Your standard ARP's might hold up, but it's a gamble. Personally, I'd switch to the L19/A1 studs just ffor piece of mind.
 

camfast

Proven Member
432
22
Jun 6, 2008
Houston, Texas
It worked well for me, but I wouldn't have guessed it would have otherwise.



I agree that the Felpro MLS is probably your best option. Your standard ARP's might hold up, but it's a gamble. Personally, I'd switch to the L19/A1 studs just ffor piece of mind.

That sounds good and L19 will be. Thanks for the advice guys!
 

u2slow

Proven Member
155
1
Feb 21, 2004
Lawrenceburg, Kentucky
You better make sure the mating surfaces of the block and head are nice and smooth. If they`re not, it won`t matter what HG/fastener you use.
 

u2slow

Proven Member
155
1
Feb 21, 2004
Lawrenceburg, Kentucky
The standard machine shop finish on the mating surfaces will not be smooth enough most of the time. Have you done the fingernail test? Can you see the cutting marks?
 

awddsm95

Proven Member
96
2
May 2, 2004
Uniontown, Ohio
By far, the Felpro Permatorque MLS head gasket is the best gasket for the DSM application. It was litterally a God-send for the high power cars when this gasket came out. Instead of blowing gaskets 2-3 times a season, cars could go all season running 8-9 second passes. Truely awesome gasket.

Now, as some have mentioned, the machining surface on the head and block is critical. If the surface finish is sub-par, it really does not matter what head gasket you are running. The smoother the better for MLS gaskets. Period. There are some guys that say smoother than a 30-40 micro-inch finish is good enough, but hearing from some of the head gasket manufacturers, I dont really think that you can go too smooth for a MLS.

I took a profilometer (measures surface roughness) to the machine shop that does my work. Basically, with the fly-cutters and the machines adjusted properly, they were able to maintain a surface roughness between 25 and 40 micro-inches depending on what angle you position the tip to the cut. This might be adequate to seal most applications, but that does not mean that every machine shop has that capability with their machines and cutters. With the surface grinding machines (using grinding stones) the shop could achieve a surface roughness just under 10 micro inches (~7 uin to be exact) and it did not matter the angle of the profilometer.

If you have an option, I would suggest grinding the block and head. If the machine shop does not have that capability, they might have a lapping plate to use. You can always hand lap the fly-cut surface yourself using a thick piece of steel that has been machined perfectly flat on one side. Use that and some ~600-800 grit w/WD40 and hand lap each surface until you do not see any machining marks. As long as the surface is flat and not "warped", this will give you the surface you need to seal a MLS head gasket, every time.

As far as the L19, A1 head studs vs. standard ARP... I would suggest that the L19's and A1's can offer higher clamping loads, but that requires you to apply more torque to the studs to acheive this. Our cylinder heads can not really take the increase load. To be honest, at those loads, you begin to crush the seats around the studs. The structure simply cant take all that the L19 and A1's have to offer. I would really suggest saving the money and going with standard ARPs. A lot of the 8 and 9 second cars run the standard ARPs without issue.
 

camfast

Proven Member
432
22
Jun 6, 2008
Houston, Texas
The standard machine shop finish on the mating surfaces will not be smooth enough most of the time. Have you done the fingernail test? Can you see the cutting marks?

Thanks for the info u2slow. The cylinder head has some swirls but it looks relatively smooth. i can do the fingernail test though.
 

camfast

Proven Member
432
22
Jun 6, 2008
Houston, Texas
By far, the Felpro Permatorque MLS head gasket is the best gasket for the DSM application. It was litterally a God-send for the high power cars when this gasket came out. Instead of blowing gaskets 2-3 times a season, cars could go all season running 8-9 second passes. Truely awesome gasket.

Now, as some have mentioned, the machining surface on the head and block is critical. If the surface finish is sub-par, it really does not matter what head gasket you are running. The smoother the better for MLS gaskets. Period. There are some guys that say smoother than a 30-40 micro-inch finish is good enough, but hearing from some of the head gasket manufacturers, I dont really think that you can go too smooth for a MLS.

I took a profilometer (measures surface roughness) to the machine shop that does my work. Basically, with the fly-cutters and the machines adjusted properly, they were able to maintain a surface roughness between 25 and 40 micro-inches depending on what angle you position the tip to the cut. This might be adequate to seal most applications, but that does not mean that every machine shop has that capability with their machines and cutters. With the surface grinding machines (using grinding stones) the shop could achieve a surface roughness just under 10 micro inches (~7 uin to be exact) and it did not matter the angle of the profilometer.

If you have an option, I would suggest grinding the block and head. If the machine shop does not have that capability, they might have a lapping plate to use. You can always hand lap the fly-cut surface yourself using a thick piece of steel that has been machined perfectly flat on one side. Use that and some ~600-800 grit w/WD40 and hand lap each surface until you do not see any machining marks. As long as the surface is flat and not "warped", this will give you the surface you need to seal a MLS head gasket, every time.

As far as the L19, A1 head studs vs. standard ARP... I would suggest that the L19's and A1's can offer higher clamping loads, but that requires you to apply more torque to the studs to acheive this. Our cylinder heads can not really take the increase load. To be honest, at those loads, you begin to crush the seats around the studs. The structure simply cant take all that the L19 and A1's have to offer. I would really suggest saving the money and going with standard ARPs. A lot of the 8 and 9 second cars run the standard ARPs without issue.

Wow, i didnt realize how smooth the head had to be even after get it resurfaced. So you are suggesting that i get 600-800 grit paper and hand lap the surface until the marks are gone?

thanks
 

dsmfa9nutter

Proven Member
1,025
4
May 9, 2005
Nowhere, Wisconsin
NEVER hand sand a head/block. There is no way you can get the perfect finish that a machine will give by hand.
 

1sick91tsi

Proven Member
150
1
Feb 13, 2004
pipersville, Pennsylvania
It seems to me anymore a lot of people spend much more mind to this issue then really needed. I run a stock composite head gasket, regular arp head studs torqued to spec. I just dyno'd the car this weekend, with NO fan infront of the car to cool the intercooler or coolant temps and made 3 pulls within 3 mins. at 35psi on pump and meth it made 574whp 464wtq. :cool: The car gets beat on daily like this and I have had no issues. Its all in the tune, if you have a good tune your good to go. Not to mention the composite head gasket acts like a fuse, if something is really that far off it will pop. On a mls head gasket you havea good chance of melting down a piston or worse.
 

awddsm95

Proven Member
96
2
May 2, 2004
Uniontown, Ohio
You do not want to sand the head with just your hand. Use A peice of machined steel bar stock that is 2"x2"x12" with one side machined perfectly flat. This has worked quite well for me for many heads. This is something that a lot of other high power guys have done before as well, because some machine shops cant get the surface finish needed to seal a MLS gasket at extremely high cylinder pressures, like those generated when you are putting out between 700 - 1100 hp.

From my experience, the smoother the better with MLS.
 
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