Metal Headgasket style/thickness

[Supraclean]

A little background info for you guys before I ask my main questions.

I have owned my 92 gtst for about 7months now and have loved every minute of it. I now find myself wanting more and finished the tuneup base mods. I am now into complete topmount turbo and front face plenum design and trying to wrap up the process the a solid head gasket.

With all the supporting mods to support 320whp these are the things I would like to finish up.

Metalhead gasket = I already have choosen not to go with the cosmetic as have heard to many bad things. Obvously im going to get the block decked and head checked if its warped. Also going with arp head studs. If you were going to rebuild an rb20 what headgasket would you use and why?

The car is going to be a summer warrior/weekend drifter. So its not like im gonig to be running it at the highest boost for track or lap times. However I wanted more then the stock 7 pounds of boost. I was thinking in the 10-12 pounds of boost range with my turbo setup and tune ect that I would reach that. That been said I want to get a good metal headgasket and make the right moves to make it fit.

Let me know what you think, yuor opions. If ya need or want a list of mods that I have or plan I can list em maybe that can help this process out.

[j-ran]

for an rb20 I would use an OEM headgasket, I think most of the headgasket problems in rb20 motors are results of headstuds stretching. I've heard from lots of people that if you just go with the arp studs and oem gasket you will be fine...

[mcfly]

Oem gasket is good for huge horsepower if you keep the head planted properly and the engine tune healthy.

With the 10mm arp studs you have to watch bolt stretch when torquing them. As you should any stud but more so the 10mm's ones as even under their tq specs they have been known to deform.

[j-ran]

^yes, and i believe you will get a better seal with an oem style gasket as well.

[Supraclean]

Ok thankx guys, yea ill get that done. Run her on the dyno. Compression test and re check torque on the studs. Side note what do you rb20 guys run for boost? I know every application very s but do you the running a solid 12 boost is safe? Or would I be able to run 14?

[rb-racer]

14 psi is considered a safe compromise

[M13]

Hit 20 PSI on the highway this weekend and has been great.

I have ARP headstuds and TOMEI 1.2mm MLS HG

[Supraclean]

Your rb20 sounds like a beast Mike. Did ya get ur HG threw Ztune?

[M13]

Your rb20 sounds like a beast Mike. Did ya get ur HG threw Ztune?

No I got it from a good buddy on here. I owe him a Tomei HG now, but it may just be an RB26 one in the future. (he lucked out on that didn't he)

Ztune would have a great price, it's just that my buddy ordered one for his build then never did it, but I needed a HG ASAP when closing up my build in August 2009.

[Skym]

Interesting.

1.2mm, 80.5mm headgasket. Stock headgasket should be 1.2mm.

Tomei 1.2mm, 80.5mm metal headgasket for RB20DET -

http://www.tomei-p.co.jp/_2003web-catalogue/e105_RB20_gasket.html

ACL metal headgasket for RB20DET (1.3mm thick) -

http://www.aclperformance.com.au/NissanRB20DETGaskets.htm

The advantage of using a metal headgasket, is if the aluminium head gets hot enough, warps, it doesn't crush the metal headgasket as easily and break seal around cylinders. Stock headgasket would crush, break seal around cylinders (add higher boost levels to the mix which adds heat, pressure against seal around cylinders), resulting in low compression or blown engine. More so if you run leaner A/F ratio's to extract most hp from engine or use engine on a racetrack with lean A/F ratio's that raise cylinder temps and add low octane gas with higher boost levels. The stronger, thicker seal around cylinder with metal headgasket is for reliability when running higher boost levels.

As far as I know you should feel that engine has less and less punch over time, then suddenly stock headgasket lets go when running high boost levels and thrashing car.

With stock headgasket, keep A/F ratio safe (rich) and boost levels down and you should be ok (adding a decent cooling system like aftermarket radiator, engine oilcooler, etc helps to keep engine, cylinder head temps down). Some recommend 1bar max with stock headgasket + stock turbo. Or lower boost level with bigger turbo, stock headgasket. That's for reliability. You can run higher boost levels, but engine doesn't last long if thrashed hard enough.

The best head gasket is a headgasket that's made of copper as it doesn't crush and holds the seal. Used on engines that run on methonal, etc. But the downside, is something else becomes the weak point.

About head studs, I thought it depends on what tenstile strength ARP headbolt you use (application) -

http://www.arp-bolts.com/Tech/T2_MetalsPages/T2_02_MaterialSpecs1.html

A ARP head stud with lower tenstile strength probably would stretch, head lift's when running enough boost with a huge turbo.

[mcfly]

Because the stock headgasket is semi metallic, same materials as on the rb26, one can confirm that the gasket is good for at least 1.7 bar and 700 whp.

[Supraclean]

Thankyou again guys, its like two ends of the extremes here. Im not going to be running a stock turbo and already have all the cooling mods setup expect the cooler. Which I plan on getning before the car is up and running on a dyno for the tune. I guess it all going to come down to what boost im going to be running no make 320-350 whp. I mean I dont want to go any higher with a stock bottom end is my thought process.

I wonder how hot the block gets as it is? I mean I dont have much experiance with A/f ratios yet and do plan of geting them in my gauge setup.
I kinda like the idea of bigger turbo stock headgasket, as im going with a gt2871. Not a huge upgrade but more then enough to get the powerband and hp I want.

Last but not least if I can read that properly the 1.2mm, in a 80.5 bore only comes in bead style? Not super grommet?

[Skym]

Interesting.

Like I said above, stock headgasket can hold for short burst's (dyno, short run on road, overtaking, etc), but put car on racetrack and thrash it lap after lap to get engine temps up, headgasket won't last long. I saw one R32 RB20DET with 22psi from TD05 turbo and had stock headgasket (dyno only and is in SAU RB20DET dyno result thread). But they reved engine to only 6000rpm (higher boost level made up for lack of revs and is one trick tuners use to reduce inertial load on bottomend). There was another R32 RB20DET in Australia that ran 1.1bar from HKS 25/30 and stock headgasket failed (car was driven very hard and didn't have cooling mods like engine oilcooler, etc and A/F ratio was leanish). I hear they ran stock headgasket on Gibson GTS-R and headgasket didn't last long on racetrack.

Shortblock is quite thick on RB20DET (strong). Has more meat between cylinder, water, oil gallery's. At least that's what I've noticed when a N1 RB26 shortblock was next to a RB20DET shortblock. Shortblock would need higher temps than cylinder head to warp it (made of iron).

The head is the problem, as it's made of aluminium that warps at lower temperatures (100-110 degrees). Easy to achieve those temperatures when you don't have a good cooling system i.e low temp thermostat, engine oilcooler, radiator, etc when thrashing car on racetrack. Even lack of a air separation bottle can cause airlock and make engine overheat.

At a minimum for engine cooling, I would recommend a engine oilcooler (reduces oil temps, heat on bottomend bearings, turbo bearings, etc).

[Supraclean]

That makes sence, and for me driving it around town it usually never goes passed 6000 rpm. However I do like to push it harder on the weekend and hopefully take it out to some drift practices. So if I do go with a MH ill just have to make your that Im not running low boost pressures and a decent temperatures. I dont think my car will see 20 psi ever but maybe 14-16 sounds like a better range for me. Thankyou again.

[Skym]

Also......

My car runs 12psi with a bigger turbo all day everyday. Engine still has stock headgasket, cooling system (radiator, thermostat, etc).

Super Grommet is a Grommet type headgasket + Beadtype headgasket in one headgasket, as shown in link below -

http://www.tomei-p.co.jp/_2003web-catalogue/e102_gasket.html

Bead type should be ok for the boost levels you are running. Super Grommet would be for RB24 that can run higher boost levels. Like they said in small print under diagrams in link above, different level of sealing.

[Allan74]

Also......

My car runs 12psi with a bigger turbo all day everyday. Engine still has stock headgasket, cooling system (radiator, thermostat, etc).

Super Grommet is a Grommet type headgasket + Beadtype headgasket in one headgasket, as shown in link below -

http://www.tomei-p.co.jp/_2003web-catalogue/e102_gasket.html

Bead type should be ok for the boost levels you are running. Super Grommet would be for RB24 that can run higher boost levels. Like they said in small print under diagrams in link above, different level of sealing.

Skym, I am beginning to think your car is imaginary, as I don't believe we have ever seen any pics of it.

[Skym]

Interesting.

No, not imaginary. :p

[Allan74]

Interesting.

[Skym]

Amazing. :D

[Allan74]

STFU and post pics of your car.....N O W

[mcfly]

Interesting.

No, not imaginary. :p

do they not have cameras in your country Cam?

[Zacho]

yeah but they take pics upside down.

[Skym]

do they not have cameras in your country Cam?

Yes, they do. Who's Cam???

I just don't like to show my car, as I know the consequences of doing this. Once photo's of car are on the internet, they are permanent. Most pro crooks search the net or look at forums for next car they can steal. Yes, some crooks are internet savy.

People wonder why after they show their car on internet (forums), in magazine or at a carshow, that their car gets stolen or broken into. Well it's obvious if you know that pro crooks are internet savy.

I just enjoy the car for what it is. I don't need to show it off.

[j-ran]

Skym, all those examples of failing stock headgaskets... those are race teams (gibsons), they know what they are getting into, they are professionals... why did they decide to use a stock headgasket? There are big advantages to not using a metal headgasket is all I'm saying.

[Supraclean]

So j ran if your engine had 130xxx kms and was geting headwork done ectn you would stick a new oem hg in?

[j-ran]

absolutely, remember, it was a stock gasket that lasted 130xxx kms... nothing wrong with that. I've also heard that your headgasket can be considered a fail-safe, meaning that you want your headgasket to go before say, a piston.

Also I'm not sure if a metal headgasket will seal as easy as an oem as they don't compress very much when you torque them.

[Supraclean]

This is true, so worst case scenario is I throw and oem one in and run my 14 - 16. I mean I'm just guessing as this is my first experience with a setup like this. Hell if it blows up Rips Rb25 here I come.

[Skym]

Somebody posted a print (I think was from Eric Hsu blog) showing the difference between a cheap metal headgasket, stock headgasket, Cosworth metal headgasket seals (4cyl). The seal on Cosworth metal headgasket looked like a solid line. The seal on stock headgasket looked weak in spots and doesn't look like it would hold up under higher boost levels for long periods.

Here's the print -

http://jdm-insider.com/Blogs/Eric/wp-content/uploads/2007/10/gaskets.jpg

Going by that print, I wouldn't trust a stock headgasket. One thing you could do with stock headgasket is fit O rings, which should create a stronger seal around each cylinder.

J-ran, I gather it was a stock GTS-R RB20DET engine with Gibson. I read they were only producing something like 370hp at engine when stock headgasket failed. But it doesn't make sense to me, as they had the DR30 with 4cyl before RB20DET, so would already know that engine would need metal headgasket. Unless they were testing limits of stock RB20DET engine under race conditions???

The other case was with stock R32 RB20DET engine and pushing the ECU tune to extract every last drop of hp and lack of engine oilcooler, upgraded radiator, etc when car was thrashed.

[Allan74]

I just don't like to show my car, as I know the consequences of doing this. Once photo's of car are on the internet, they are permanent. Most pro crooks search the net or look at forums for next car they can steal. Yes, some crooks are internet savy.

People wonder why after they show their car on internet (forums), in magazine or at a carshow, that their car gets stolen or broken into. Well it's obvious if you know that pro crooks are internet savy.

I just enjoy the car for what it is. I don't need to show it off.

Skym, you seem to have an answer for everything. Copyright Laws, protecting your car.....and frankly, it's getting OLD rather fast.

After reading the above post, I don't trust you. Simple as that.

If you don't trust Us, then why in hell should we return the favour ?

I'll give you a little tip:
In 99% of cases out there, when a Boyfriend accuses his Girl of CHEATING.....it's because HE ALREADY HAS and lives with that on his concience.

Shoe on the other foot, Pot calling the kettle........and whatever Cliche you want to choose from the literally MILLION available for situations such as this.

Hey, come to think of it......you seem to be a little 'Internet Savy' don't you ? Those who live in glass houses......?

[GRIP]

Why are you riding Skym so hard ? its up to him if he wants to post a pic of his car or not

Back on topic here, block and head prep is also a factor on how well the head gasket will hold up
decking and O-ringing the block will make make for a stronger seal as well

[j-ran]

Ok, a cosworth headgasket is going to be good, keep in mind it was probably installed by someone who assembles formula 1 engines for a living. Also, Eric Hsu works for cosworth. All Im saying is that for the boost levels and power Supraclean is going to be running, ARP studs are going to be the difference in whether or not his OEM headgasket will fail.

[mcfly]

Why are you riding Skym so hard ? its up to him if he wants to post a pic of his car or not

Back on topic here, block and head prep is also a factor on how well the head gasket will hold up
decking and O-ringing the block will make make for a stronger seal as well

if you are o-ringing your block you might as well get a solid copper headgasket as well:p

[Skym]

Skym, you seem to have an answer for everything. Copyright Laws, protecting your car.....and frankly, it's getting OLD rather fast.

After reading the above post, I don't trust you. Simple as that.

If you don't trust Us, then why in hell should we return the favour ?

Fair enough.

It's not about trusting you or other forum members. It's about other people outside the forum members that can view a thread and take photo, post on other forums. Easy to do when you can use a Google bot / spider that no forum (apart from one) that I've seen, which has a defence against.

If you want, I can send a photo to you, would that make you happy?? But I don't want it on the internet.

[Allan74]

The fact that you are willing is good enough for me. I don't need to see it personally.

[Skym]

Allan74, I've already sent photo's of part of my car to a GTRC member.

J-ran, also skimming the block, head, not just the head helps with seal. I just don't like the idea of stock headgasket crushing. Although headgasket's have come along way since the 90's and the new headgasket's are alot better. Nissan probably sell new style headgasket's, not some that were made back in 90's when car was made. But that print kind of says the opposite.

[M13]

Most new engines nowadays have MLS HG.

I wonder why? (rhetorical question)

[Supraclean]

Yes on topic please. So would I just take the cams out and take the block and head into the machine shop? Or do the valves and springs have to come out to?

[Skym]

You'll need to change valve seals while head is off and you can't change those while valve springs, etc are installed. Also head needs to be pressure tested for leaking valves and cutting valve seats, etc if any valves are leaking. So valves, etc would need to be removed by cylinder head specialist.

It's usually the head that's out of square due to being made of aluminium that warps at lower temperatures than a iron block (more so if engine has overheated in the past and you don't know it has). If you run a ruler from bottom right corner to top left corner and bottom left to top right corner on deck of head, should see daylight between ruler, deck of head if head is warped.

Some skim the block at same time to make sure seal is perfect on both sides of headgasket. But you would be pulling pistons, etc out to do this and be setting block up for forged pistons, etc.

[Supraclean]

Thankyou Skym, looks like all my paychecks are going to Mike at Ztune:P