The title basically says it. I'm gonna be running 20-23 psi on my freshly rebuilt 6bolt. I was just wonder if you think i should go thorugh the trouble of getting a metal headgasket and arp headstuds for 23psi and under. Or maybe just the studs so i can torque it down more with the stock headgasket?

Thoughts please.

Thanks,
Ryan

One more question:

can the arp studs be reused? I know this has been asked but i couldnt find an answer.

They can be reused and it would be easier to put the head gasket in now then have to later.

A metal headgasket is a great idea when you have the opportunity. However, only do this if the head and block have been decked and machined so that they are perfectly flat. If they have been cleaned up and machined real nice, go with a Mitsubishi 4 layer metal headgasket.

As far as the 7 bolt headstuds I have been hearing some stories about these. I have heard that they "stretch" after they are torqued down. I am not sure if this only applies to only stock 7 bolt head studs or not. Can some one please clear this up for me and the original poster.

I ran 20psi for quite awhile with ARP's and a NAPA headgasket with no problems.

If you do go with a metal HG, like the last guy said, head and block must be decked to a mirror finish and copper coat or you WILL push coolant.

<<<24psi on stock gasket and studs, driven and boosted dailey. Arp studs and a mitsu multilayer gasket is the way to go. good luck with the rebuild.

Whatever you are planninng on torquing your head bolts/studs at I hope you've had the torque plate set at while it was being bored/honed out. The clamp force does distort the cyl. walls some. Im using a MLS head gasket, and NO copper spray. I promise im not pushing coolant, or oil, or anything. Extra torque wont help keep the bolts/gaskets from stretching/blowing from detonation either, which is what does it in the first place.

I'm running 26psi daily on a stock Mitsu composite gasket with ARP studs. I did specify to the Machinist what torque to use on the torque plate during the bore/hone and made sure that the block deck/head were flat and in spec. (I actually bought a straight edge from www.goodson.com). I also am fortunate in that my combination of parts can handle these boost levels without knocking.

My engine has been running strong for 18 months, and as I commute in the car 70 miles a day, it sees a lot of mileage. I've run at the track several times at 28psi and also seem to find an excuse to bounce her off the 8500rpm rev limiter at least once a day, so my car is by no means pampered.

For your goals, the stock Mitsu gasket will work fine, but the ARP hardware is a MUST for any modified DSM.

98autogstspyder said:

As far as the 7 bolt headstuds I have been hearing some stories about these. I have heard that they "stretch" after they are torqued down. I am not sure if this only applies to only stock 7 bolt head studs or not. Can some one please clear this up for me and the original poster.

Click to expand...

yes. after about 22 psi the head actually begins to lift off the block. the "stretching" is referred to the stock headbolts expanding under all that load. a stock headbolt doesn't have acurate torque readings compared to the arp headstuds once they are torqued down.

I guess the story of the stock 7 bolt head STUDS is different from the stock 6 bolt head BOLTS. I have read somewhere on this forum that the stock 6 bolt head bolts will be stronger than the 7 bolt head studs or whatever they are. I can only speak for the 6 bolt, seeing how thats what I have now... Can somebody confirm this?

6 bolt studs are 12mm thick and 7 bolt are 11mm.

RoasT BeeF said:

I ran 20psi for quite awhile with ARP's and a NAPA headgasket with no problems.

If you do go with a metal HG, like the last guy said, head and block must be decked to a mirror finish and copper coat or you WILL push coolant.

Click to expand...

DSM Urban myth #345325

Have the head checked and deck it if the machinist says it needs it. Clean all the old gasket crap off the block and clean any oil or coolant off. Let it dry completely, spray both sides of the 4-layer with an even coat of copper spray, and TQ the ARPS in the right sequence and steps. Hell, I just did this AGAIN to my Spyder a couple weeks ago and I'm not pushing coolant at 24psi (42 lbs/min). I've never had this original block surfaced.

i have been pushing 24psi on arp studs and a mitsubishi gasket. i been told that you might as well do the gasket and the studs at the same time. its more reliable .save your self money and problems than if you wait

thanks guys

i got arp studs and a 4layer HG.

arash15 said:

yes. after about 22 psi the head actually begins to lift off the block. the "stretching" is referred to the stock headbolts expanding under all that load. a stock headbolt doesn't have acurate torque readings compared to the arp headstuds once they are torqued down.

Click to expand...

From what I have researched, I've always read it's more like 25 psi where the stock studs and head start to lift. I run a FP ported B28 along with HKS cams and a 75 shot at 24 psi while nitrous engaged, and have had no problems at all as of yet.

talon_boy69 said:

6 bolt studs are 12mm thick and 7 bolt are 11mm.

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So therefor making the 6 bolt head bolts more "high performance" tolerant, correct?

Turbo Talon DL said:

So therefor making the 6 bolt head bolts more "high performance" tolerant, correct?

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Maybe in the grand scheme of things but I wouldn't go claiming that as a benifit of a 6 bolt swap. 11mm ARPs are going to hold as much power as 90% of DSMers can throw at them.

Turbo Talon DL said:

So therefor making the 6 bolt head bolts more "high performance" tolerant, correct?

Click to expand...

I doubt it. It doesn't seem to hold Evos back.

RoasT BeeF said:

If you do go with a metal HG, like the last guy said, head and block must be decked to a mirror finish and copper coat or you WILL push coolant.

Click to expand...

!

as long as the surfaces are clean and flat, a Mitsu metal gasket and ARP studs are the way to go. I have run over 28 psi on this setup and have NEVER used copper spray...not once.

ive also NEVER pushed coolant....

A thread on NABR a while back suggested stock 1g headstuds could be stronger than ARPs.

Could you post the link and was their any evidence, other than anecdotal, that proved this?

In my opinion, if the car is daily driven, I'd go with a stock head gasket and ARPs. The ARPs won't stretch like the stock 6bolt head studs.


If it were mostly a track car, with occasional daily driving, I'd go and opt for a metal gasket.
When I used to drag race heavily with my daily driver, I used to spin bearings from detonation because I had an oringed block. I wasn't a great tuner at the time, and dataloging for my other car wasn't available.


In short, blowing the headgasket ain't such a bad thing when you think of how much a rebuild costs. It's irritating, but it's much cheaper than replacing bearings or ring lands. I'm not suggesting you're a bad tuner, but it's just my opinion that the head gasket is a safety valve for us who can't afford full blown race cars.

Upgrading the head gasket and adding studs is a good idea because you may want to run higher boost levels eventually and add a bigger turbo. Then that is one step that you don't have to worry about at that point. I personally like the Cometic HP gaskets, and I always use ARP studs in the motors I put together and they can be re used many times with no worries of stretch.

98spydert said:

DSM Urban myth #345325

Have the head checked and deck it if the machinist says it needs it. Clean all the old gasket crap off the block and clean any oil or coolant off. Let it dry completely, spray both sides of the 4-layer with an even coat of copper spray, and TQ the ARPS in the right sequence and steps. Hell, I just did this AGAIN to my Spyder a couple weeks ago and I'm not pushing coolant at 24psi (42 lbs/min). I've never had this original block surfaced.

Click to expand...

I would be careful about calling that a myth. Having the head and block decked is a necessary precaution.

Stapl3 said:

A thread on NABR a while back suggested stock 1g headstuds could be stronger than ARPs.

Click to expand...

I have also heard about this. There is some R&D going on with this right now. It was just suggested by several people that the stock 6 bolt head studs MIGHT be stronger than the arp versions. I also have seen this on NABR and from a friend of mine. However under the circumstances, since this has not yet been proven, go with the arp head studs as being the stronger item.