2G Composite or MLS?

[krummel21]

I have replaced 2 head gaskets in the 6000 miles and want to make sure I don't have to do it again. The last head gasket was a composite and it started pushing coolant at 25 psi while it was on the dyno being tuned. When I removed the head the gasket looked fine. I assume the bolts strechted, standard ARPs were on at the time?

I have had the head checked and it is flat and has a very good finish on it. The block on the other hand is flat and smooth but it is far from a mirror finish.

I have also purchased L19 Headbolts for this install.


My goals:

26-29psi on a 50 trim running E85.

Which headgasket should I run?


I was looking at the perma-torque MLS, does it do a better job at sealing water and oil than the composite version does?

Thanks!

 

[red_devil]

I have replaced 2 head gaskets in the 6000 miles and want to make sure I don't have to do it again. The last head gasket was a composite and it started pushing coolant at 25 psi while it was on the dyno being tuned. When I removed the head the gasket looked fine. I assume the bolts strechted, standard ARPs were on at the time?

I have had the head checked and it is flat and has a very good finish on it. The block on the other hand is flat and smooth but it is far from a mirror finish.
I have also purchased L19 Headbolts for this install.


My goals:

26-29psi on a 50 trim running E85.

Which headgasket should I run?


I was looking at the perma-torque MLS, does it do a better job at sealing water and oil than the composite version does?

Thanks!

Composite and L19's if the surfaces are not perfect.

 

[1slow03cobra]

My car has mls and has been fine for about 6 months, according to arp the bolts are a one time use?? hell i have had mine on my camaro for 3 years and multiple gaskets have been on that.

 

[krummel21]

What is the max I can take the 50 trim with composite and L19s? Is there anything I can put on the composite to help with coolant pushing

 

[red_devil]

http://www.dsmtuners.com/forums/newbie-forum/390490-max-boost-composite-gasket.html

They have held over 40psi and 60+lbs/min

 

[My1GLaser]

How far from a mirror finish? Can you drag your fingernail across it and catch hi & lo spots?

You can hand lap the block to smooth it out. I have a 1"x3"x10" steel bar that I wrap in emory cloth and hand lapped my block to a mirror finish. I went from 100 grit to 1500 grit. I did this with the motor in the car. I plugged the coolant/oil holes in the block with pieces of blue shop towels, and stuffed some in the cyl bores.

You can use copper spray on the HG.

 

[Lou98GSX]

i use a factory MLS with arp studs torqued at 90 ft pounds with a gasket spray for added insurance . run 27 psi with no problems .

 

[untouchablecc]

i use a factory MLS with arp studs torqued at 90 ft pounds with a gasket spray for added insurance . run 27 psi with no problems .

I have read that using the copper spray gasket is excellent for a composite gasket but not so much for the MLS. Just a mirror finish for a MLS. I dont know if this is proper but I have reused cometic and oem MLS headgaskets without pushing coolant but It seems like after 3 removals the oem one is shot.

Im running standard ARPs. I have had the same set for 4 years and the same head off a half dozen times. I have had the head and block decked to a mirror finish once in 4 years and I have no problems with pushing coolant.

 

[livedsm4g63]

Ive used a mitsu mls with copper spray on both of my builds. Arp's torqued to around 95 ft/lbs.

 

[WES_393]

A composite gasket with ARP studs will work fine for your goals. Maybe upgrade to L19 studs for peace of mind, but a MLS gasket is a bit overkill. The biggest factor is your tune. Knock, detonation, excessive timing, etc will damage any engine. With an MLS gasket you'll just crack a ring instead of blowing the head gasket. So if you have blown 2 head gaskets in 6,000 miles, I would suspect issues with the mating surfaces, head studs, or tune. Especially with E85 since it's much harder to see knock from timing alone.

I'm running a Mitsu Composite gasket with ARP standards. Currently at 25psi (16g), 17* of peak timing, and hovering around 12:1 AFR's. Not a hint of head gasket damage in 2k miles, even with noobish tuning mistakes.

 

[BogusSVO]

2 HG in 6k miles...

For what you are working towards, I would say you have a block surface issue.

Yes I understand the block is flat.

But that dose not mean you do not have "rolled" edges around the water ports in the block, or slight grooves from the fire rings biting into the block.

 

[H@xtGSX]

Yea, there has to be something wrong. I have a Felpro composite with MP35N studs at 25 psi with an 18g, and there isn't any problems with it at all. I would be looking at the mating surfaces... It's that or your putting in the gasket upside-down and backwards, and if that's the case, there is no cure for stupid.

 

[krummel21]

What are some things that i should look for on the block?

 

[viperlp01]

O my... I just did a test with my decking machine to see how bad people sanding there blocks messes with the straightness of the deck and lets say with a .004 cut it barely touched spots.

Stretching head studs at 25psi.... I am on standard arps at 37psi with 10:1 CR... I doubt your stretching them.

A composite will do just fine with standard arps if the block and head are straight and the tune is right.

 

[BogusSVO]

This was a RB26DETT I had to deck the block on, due to damagage in shipping, but it had gone thu a couple headgaskets, and needed decked any way.

This block surface was horrid.

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I cut .002 at this point and you can still see, gasket core imprinting, along with where the fire ring dug in.

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on the left you can see where one of the casting support rods had moved up above the deck, on the right, just above the head bolt hole the deck was distorted.

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I had used some blue lay out dye before this pass, I cut .001 for a total of .003 removed.

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The warter port on the right has sunk and lead right to the fire ring
The water port had a dent and I had that bronzed welded, but the blue dye still shows low around the water port.

Also to note are the scratches under the head bolt hole ( shipping damage)

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This pic shows that whomever put the champher on the block rolled the cylinder edge a bit, since it is inside the fire ring of the HG it will not hinder sealing of the HG.


Top of the pic, you now can see sharper edges to the water port.
Total removed was .006

OP There is really no way to check the deck with out it being surfaced .001 a pass.
Even a .0015 feeler gauge would not pick this up, beacuse most feeler gauges are about .500 wide, and would just bride over that gap.

But due to the age of the block, and 2 HG on your ownership of it, and how many more before you bought it? How was the gasket surface cleaned then???



I found pics of a 4g63 Block I decked.

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See on the right of the pic, note the huge low spot.

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Not a real good pic, but you can see where the cutter hit, and did not hit.

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With that much distortion of the block deck, now you can see what issues the HG would have sealing.



I hate to be the one to say it, but pull your short block, dissasemble the rest of the engine, and get the block decked.

 

[red_devil]

Just wish you would do some work for some members on here

 

[SpiderGST]

Jesus can you say low spots . Also he does do engine work for people on the forums but sometimes you get what you pay for and with Bogus it is that and it is done right the first time and some people dont want to pay the price. I would have let him build my motor for me if he was only closer. I hate how high shipping has gotten.

 

[krummel21]

Here is some pictures of my head.

 

[H@xtGSX]

That's decked?? No way... Table decked, maybe, but that doesn't look like a mill went over it. I'd be willing to put $20 on you having a low spot, just like shown above.

 

[krummel21]

The block hasn't been decked. This is what it has looked like every time I put a head on.. There probably isn't any easy way of checking for low spots, is there?

 

[alphamythos]

go mls. and yes decking would be a good idea. otherwise you lose power and have to worry about a weak seal causing the gasket to crack or leak in time.

 

[danielkile]

as long as you have head studs composit should work well for you, well it is for me

 

[BogusSVO]

The block hasn't been decked. This is what it has looked like every time I put a head on.. There probably isn't any easy way of checking for low spots, is there?

No there is not an easy way to check, most the time I find the rolled edges, and small low spots one I am decking the block.

go mls. and yes decking would be a good idea. otherwise you lose power and have to worry about a weak seal causing the gasket to crack or leak in time.

Why MLS? Felpro and OE composite HG have been proven to hold the boost level and power the OP is shooting for.

as long as you have head studs composit should work well for you, well it is for me

Well if you read the thread, you would have seen the OP has that set up, but keeps blowing HG, it is not the gasket that is failing, but the surface of the block that will not allow the HG to do its job.

A blown HG is not the cause of a problem, but the result of a problem

 

[spadepro22]

I trust my builder, but since my last motor walked under 1,000 miles I'm pretty much questioning him/everything(not his fault). I always ask a ton of questions anyway, but he wants me to go with a metal head gasket and after reseaching and reading threads like this, it seems head and block must be perfect to run a metal hg. I kinda wanting to go with composite to be on the safe side, becasue after spending 10k since November of 2012, I can't afford pulling the head due to the head or block wasn't machined good enough for a metal gasket. Sorry for the rant.

 

[hondo0975]

Very good information here guys, thank you's to all.