OEM head gasket vs cosmic 1.5mm gasket

[curtains]

So I have 2 SR20DET, one black top one red top, the black top is running fine but unknowen whats been done or if anything been done to it.

The other SR (the red top) has a blowen head, but bottom ends been rebuilt (new bearings and rings I think), so I got a new head (2nd hand seems good condition from inspection) and thinking of rebuilding it, I was thinking of using the red top in my project car (as it is without an engine).

Ok so my aim is for about 320hp - 350whp just wondering if OEM gasket is good enough for this as the price differences is about $200, and since if OEM is good enough one of the engines are going to be sold anyways.

so which motor should I use? and if I'm to use the red top which gasket?

[HOOCH]

stock will not hold up to that! and cometic are not 200 look around, i just put one on mine for 100 shipped!

[curtains]

sorry NZD, about $180nzd actually (but thought i'd just be easier saying 200), prob about 120USD??

[90hatchie]

ew cometic is GARBAGE
apexi 1.1mm and your golden

[omgRWDgoodness!]

I believe he was asking about an OEM headgasket vs. a cosmic one

[kognition]

Apexi or Cosworth hg.

[Eplejus]

The OEM headgasket can easy take ~400whp. As long as you got cooling & detonation/pinging under control. Heat and bad mapping/tune is what kills the gasket.

My engine been pushing 334whp for 3 year now with OEM gasket, and shows no signs of weakning. Done plenty of trackdays.

[curtains]

OEM gasket it is then, sounds good

[Sileighty_85]

so one guy's engine holds a little over stock power says it can take it and you side with him?

You already have the engine out and almost apart might as well install an Apexi H/G for an ease of mind.

[s13 drifta]

I run a OEM head gasket at 15psi on a t28 daily, I wouldn't push it past that though. If you want to go past that I would recommend Apexi or Cosworth like mentioned. Cometic is garbage! Mine leaked at 10psi.

[codyace]

Originally Posted by curtains

OEM gasket it is then, sounds good

ApexI or Cosworth. Make sure you get the head/block resurfaced as well.

[Wookie384]

Can someone explain why the Apexi/Cosworth gaskets are better than Cometic? I'm just curious.

[90hatchie]

cosworth is cometic with a cosworth stamp

garage boso has tested every head gasket out there and this is there results

Felpro Head Gaskets are very similar to OEM Nissan Gaskets. I got getto on one of my cars and didn't change the head gasket, it was a used engine from Japan(it was Stock head gasket or Felpro) I ran 1.5bar of boost with VP C16 race gas, for one event. After the event I pulled the head and checked it, everything looked normal. I am not saying it is save but it my car did not have any signs of damage.

On our S15 driftcar, I have tested every head gasket in the industry, because I having issues with the combustion pressure pushing into the water jackets. Below is short/brief Research of my testing:

It started out with the BC Stroker Kit 2.4L (90mm pistons) and the 2.35L (89mm pistons). The reason I messed with the BC Stroker kit was because everyone that tried to make it work couldn't keep the engine together. My dumbass didn't believe that everyone that was doing it was doing something wrong. So I wanted to do it and show people that Garage BOSO is a good tuner shop in the States.

2006 I started this engine project, talked to a few people that were using the BC Stroker kits and see what they have experienced with. At the time there were only 3 Pro Drift team that were using it, everyone else used the 2.2L stroker (88mm) those never had problems. I built the first engine, ported the head and got everything together. got it on my dyno and started tuning, got the car running good, it is a torque monster, at idle it need more injector PW that is normal for a car to because of the stroker, but once i hit 3000rpm the the car need almost 3 times more fuel, you can begin to really hear and feel the engine wake up (just for your reference we were using an AEM EMS) I was like holy shit this engine is sick!!! then I got to 4000rpm sound even meaner and you can see the engine is still asking for more at 4200rpm at 1.3bar sounding so nice and then fuckn engine starts over heating and shooting white smoke out the exhaust, I was like fuck!!!! I killed the car!!! So I called everyone that I knew that ran this engine for Drifting (drag doesnt count cars only need to last 1/4 mile) At the time I was using a Cometic Head gasket or the Cosworth USA head gasket they are exactly the same gasket except the cosworth one has a Cosworth stamp on it and is in a Cosworth package. (Do not get tricked from companies selling you crap, I do not want to see you go through what I went throgh) Anyway, it was blowing past between the gasket. I thought it was the head gasket i changed it with a new one, same shit same point blew, changed new ARP studs-> same, change to Greddy studs with new gasket-> same. Tomei studs with new gasket-> same. Talked to some JDM tuner they recommended stock head bolts and torque them 10ft lb more than factory specs.-> that helped I can take it to 4500rpm and then explosion again!!! then used new sleeves, different machine shops doing the sleeves, differnt brand of sleeves. Still couldnt figure it out. Then talked to on of our competitors they use an Apexi head gasket and machined to out to 90mm bore and they used this GM Northstar head gasket sealant. So we tried that and it worked!!! But we were still getting heating issues. (Just for your reference at the time no one makes 90mm bore headgaskets. ) After the first race the engine dies again, me and Ross in that year from the end of 2006 to the end of 2007 within that time f rame we were the masters for SR swaps 15 engine died. I was like FUCK SR Engines!!! But our dumbass's said lets start over and see what the fuck we are doing wrong. Thing thing thing.......... the issue we are Talked to some drag friends and see what they do to keep Honda drag engines together. And searched for a company that makes custom headgaskets.

R&D: our ultimate issue high cylinder pressure pushing into the water gaskets. because the 90mm bore brings the water jackets closer the the cylinder, its such a thin clamping area the pressure just pushes by.

Our Answer: ARP head studs (for V8 application), Sleeves were stepped decked, and found that Power Enterprise makes a 90mm headgasket that has a very nice fire ring for the cylinder pressure sealing.

Result: 568Hp 460tq

Setup:
2.4L BC stroker kit
VP C16 race gas
1.4 bar Boost (at sea level)
Response faster than a SR20DET with a GT2871R Garret turbo on HKS stage 1 cams
Max torque at 4200RPM
Max RPM 9000RPM (I set limiter to 8000RPM)

Engine Management for these results: AEM EMS, APEXI Power FC D-Jetro, MOTEC M800. (certain ecus do not make more power than others, the only benefit is the compatibility of different input and out put sensor and the dataloging options) To really tell you the truth, just because it has all these options doesn't mean it is better.)
"More options = more problems and more money for tuning!!"

*** I love SR engines!!!! Seriously you need to hear this car in person, it sound really good!!

[codyace]

Originally Posted by 90hatchie

cosworth is cometic with a cosworth stamp

garage boso has tested every head gasket out there and this is there results

How recent is that test? Cosworth didn't develop their new headgasket for SR20 (including their large bore) until 3 yeras ago or so.

Eric Hsu's blog (beyond the dyno) had a huge writeup on the creation of it (which I can't find now) but I did find this update on Moto IQ:
Should You Change Your SR20DET Head Gasket? > MotoIQ > Magazine Articles

SR20DET swaps in S13/14 240SX's are quite popular here in America. One of the questions I frequently get is, "Do you think I should change my head gasket before I swap the SR in?" I always recommend changing it because it's fairly easy when the engine is sitting on a stand or even on the floor (don't crush the steel pan people!). The paper gasket is fine for 205hp and probably even ok for 280hp, but in reality it's detonation that usually destroys the stock paper head gasket. Since there are so many cheap asses that use the OEM ECUs on 91 octane in the SR20 swap world, it's even more reason to change the head gasket. Yes, the stock ECU can handle 91 octane because it can default to more retarded ignition maps, but when people start running no cats, turning up the boost, with the little piece of shit in the corner intercooler on 91 octane, knock is bound to happen because the stock ECU isn't calibrated for these mods. And with 91 octane, there is no headroom because the stock JDM ECU is probably already on it's most retarded ignition map. When knock happens, the fire ring around the cylinder in the stock gasket will eventually fail.

Bart "Hijacker" Thornton from the NICO forums, also asked me if the Cosworth gasket was as good as or better than some of the double priced JDM gaskets from Apex, Power Enterprise, or Greddy. The answer is yes, it is as good as the others. I have personally tested the Apexi and HKS SR20DET head gaskets using pressurex film when I was Chief Engineer at Apexi USA in my previous life. I can tell you that the HKS, Apexi, and Cosworth gaskets all work equally as well and not one of them works better than the other. Except that the Cosworth gasket costs about half the price. I have never tested the Greddy or Power Enterprise gaskets. The Cosworth gasket rules in the Subaru and EVO world already. It's only a matter of time before people wake up and realize they are blasting away good money on the JDM gaskets.

There is also talk that the Cosworth gasket is a cheap imitation/copy of the Greddy gasket because it is priced so low. This is the most refuckingdiculous shit I've ever heard. First of all, why does anybody need to copy anything Greddy? They make some cool turbo kits, but otherwise... The Cosworth SR20 gasket was engineered from scratch to fit ALL SR's including the VEs, DE front wheel drive, DE rear wheel drive, DET front wheel drive, and DET rear wheel drive. This means it will work with all iterations of the SR engine. Cosworth designed production turbocharged 4 banger engines long before Nissan even dreamed up the SR20 and has raced turbocharged 4 bangers much longer than the Japanese. What does this mean to you? That many Japanese technologies both OEM and tuning companies, are probably copied and/or derived from Cosworth's technology. For example, the 4AG is an econo copy of the Cosworth BDA, the SR20 is loosely derived from the BDT, the 4G63 is loosely derived from the YB, etc. Even HKS used to make parts for the Cosworth BD back in the day. Anyhow, the Cosworth stainless multi-layer gasket is Cosworth's own design. It is not a copy of anybody else's. What I'm trying to say is that Cosworth has been designing innovative engines and components for 50 years - longer than any JDM company.

(goto the link to see a image of the test, I'd link it but it's huge)

If you take a close look at the test results, you can see that the stock gasket is mediocre at best around the cylinders. The color is light red with many areas blotted in white. Then take a close look at the Cosworth gasket and you'll see how defined and red the pressure is around each cylinder. Assuming the red imprint is solid (and not blotched or clouded with white), the brighter the red, the higher the clamping force. If the red is dark colored or blotched or clouded with white, the clamping force is lower. I think the results speak for themselves.

The long awaited 90mm SR20 gasket is now available. Here's where you can buy the Cosworth gaskets. Save yourself some of your hard earned money people. Good luck with your project.

Cosworth wouldn't ever copy a Cometic gasket in this day and age.

[codyace]

And for those looking at this, here is a great article for you all on head/block prep...all to often people skip this step, and it ends up being a cause of failure:

Deck Preparation > MotoIQ > Magazine Articles

I really wonder why people don't understand how critical the condition of the sealing surfaces of the deck of a block and the fire face of the cylinder head is to head gasket sealing. Old school engines used paper gaskets so you could get away with some flaws, but modern engines use metal head gaskets which require the block/head is 1)absolutely flat and 2)is free of flaws or defects. As you can imagine, metal doesn't flex and fill defects like a paper gasket can. When I say free of flaws, I mean no scratches, nicks, and dents either. The more cylinder pressure there is (aka boost and horsepower) in an engine, the more critical flatness, surface roughness average, and perfection of the deck/head is. When you look at a factory manual and you see the spec of a block or head needing to be flat within .002", that's fine for factory horsepower levels. A quick rule of thumb I use is if you plan on doubling the horsepower, split that spec in half. So for example if a factory 280bhp RB26 has a spec of .002" for flatness, then it needs to be .001" for 560bhp. Triple the horsepower and it needs to be absolutely flat. 800+bhp is no laughing matter and the deck/head must be ABSOLUTELY flat and free of ANY defects. The surface roughness average should be also be at least half of stock. When it doubt, have the block and head lapped for the ultimate in sealing force.



The reality is that people often ignore how critical the deck and fire face are. If an engine is loosing gaskets, here's a list of potential problems:


1. Warped head

2. Warped deck of block

3. Detonation

4. Lifting of the head due to detonation and/or weak head bolts

5. Flaws on deck of block or fire face of head

6. Too much horsepower (you need bigger or higher grade studs)

7. Poor surface preparation (see below)

If you are suffering from #6, chances are you already know what I'm writing about here. I am writing this for those people who buy a brand new quality head gasket from HKS, Tomei, Cosworth, Apexi, Greddy, etc., loose a gasket, and then foolishly blame the gasket like a fucking dumb ass. The reality is that it is YOUR fault for not properly preparing the block for your horsepower level. People also like to blame head studs and of course its NEVER their tuning, but come the fuck on: how come the pros can do it right? Detonation and knock can destroy a head gasket real quick; especially if you have all forged components.


Anyhow, before I go off on a full on rant again, here's a quick tip on how to clean up the deck of a block or a fire face of a head. If the block is not flat or the head is warped, you will have to remove the engine, disassemble it, and take it to a machine shop. This tip is only for cleaning the surfaces up or repairing a minor flaw. It also works for cleaning up the deck if you're changing a head gasket with the engine in a car. You can also flatten a head if you have more time than money since aluminum is softer.



Get yourself a block of steel (thicker and heavier the better), some 400 grit sandpaper, and WD40. You'll want to take the block of steel to a machine shop to have them grind and/or lap one surface flat. GRIND, not cut. I did capitalize GRIND.



400 grit sandpaper around the steel block and use the ground surface against the deck of the block or fire face of the cylinder head, spray a shitload of WD40 on the sandpaper and surface to be flattened/repaired, and go at it with smooth strokes along the entire length of the block or head. You will also need a straight edge and feeler gauges to measure for flatness. This picture was taken for illustration only. You'll want to remove the dowels from the block before sanding so you can sand the entire surface.

That's it. As with any kind of engine building or assembly, it always takes time or money to do it right. Skipping steps will result in disaster. Pay attention to the details and you will be rewarded with an engine that performs when you need it to. Almost every engine and head built at Cosworth is done this way and trust me, we don't do it because it's fun.

[jr_ss]

Originally Posted by codyace

Cosworth wouldn't ever copy a Cometic gasket in this day and age.

This right here is a true statement. Why the hell would a company that's been in racing for six decades imitate a company that's been in business since the late 80's? They have no reason to and it would be blasphemy and a disgrace to the Cosworth name and heritage. They are a leader in their field.

[codyace]

Originally Posted by jr_ss

This right here is a true statement. Why the hell would a company that's been in racing for six decades imitate a company that's been in business since the late 80's? They have no reason to and it would be blasphemy and a disgrace to the Cosworth name and heritage. They are a leader in their field.

Most certainly. Seems to me like that Garage Bozo test was a bit of a 'parts changing adventure' as I think much of their issue was from machine work if it was pushing coolant like that. With a Sleeved engine, anything could be possible, and asking a MHG to take up the slack in (assuming) a poor machine shop is a bit unfair.

With that said however, I know early on in the large bore SR world there were issues with companies not making a decent big bore gasket, and that's why Cosworth went ahead to develop one (IIRC they may even make a 92mm one, but don't quote me on it)

[Def]

Stock S13 SR HG doing just fine here with no issues. I have maybe 4000-5000 track miles on the stock engine at this point, always run at 1 bar with a GT2876R or GT2871R with 93 octane. On the street it always sees 18 psi, and it has had about 1000 miles of 21 psi on E85 (made enough torque to slip my ACT HDSS clutch repeatedly in 4th).

That said, I'd go with a Cosworth HG. I can't believe someone said it was a Cometic copy. What a crock... They don't even look remotely similar.

Here's a pressure plot of a stock vs. Cosworth HG on an SR:




I'll give you 3 guesses as to what POS gasket is on the bottom, and two don't count...




More info:

Cosworth Big Bore Head Gaskets for Sleeved Blocks > MotoIQ > Magazine Articles

[sr20sean]

cometic are more designed for one time use then throw it out not really continuous use.

[R33E8]

I would rather see independent studies rather than Cosworth (Eric Hsu) trying to promote their head gaskets.. As far as I know, Cosworth is a completely different company from what it used to be back in it's glory days..

[HOOCH]

Don't know much about the other brands but i do know that enjuku racing uses cometic on there drift cars and im sure they are pretty beefed up cars just my 2 cents

Taken from enjukuracing.com-Cometic 1.01 Metal Head gasket Nissan SR20DET...
"This is the same headgasket used by our two Formula D drift cars running 11:1 compression with ~21 lbs of boost"

[Def]

Originally Posted by R33E8

I would rather see independent studies rather than Cosworth (Eric Hsu) trying to promote their head gaskets.. As far as I know, Cosworth is a completely different company from what it used to be back in it's glory days..

They're growing their consumer side of the business, and you can't expect F1 engine technology for a couple of hundred bucks on most components, but come on man, are you really trying to compare Cometic as an engineering company vs. Cosworth?


Eric Hsu seems to tell it like it is even if it goes against whatever is putting the bread on the table for him. I'll give him respect for that.


I see cars have HG sealing issues all the time with Cometics personally, and honestly stock SR gaskets aren't half as horrible as you'd believe reading the dumbasses that detonate theirs to death on Nissan forums.

[rbs14kouki]

my friend is runing a OEM head gasket on is sr20VET ... it was a 650whp at 28psi mustang dyno last week !!!

exemple of what i did to is block !!!
572Ci Mopar Wedge Engine Build O Ring Scribing Photo 4

[codyace]

Originally Posted by sr20sean

cometic are more designed for one time use then throw it out not really continuous use.

Again, why bother with Cometic?

Originally Posted by R33E8

I would rather see independent studies rather than Cosworth (Eric Hsu) trying to promote their head gaskets.. As far as I know, Cosworth is a completely different company from what it used to be back in it's glory days..

I'd love to know why you wouldn't trust a company who still creates F1 level parts, still creates the best stuff for the most current 'tuner' cars, and still supports it's back catalog of stuff?

Cometic on an F1 car? Show me where.

I hate to sound like a nutswinger, but Eric Hsu and his blogs are notorious for being honest, and fair. He's got all the time in the world to test his reasoning, we don't.

Originally Posted by Def

Eric Hsu seems to tell it like it is even if it goes against whatever is putting the bread on the table for him. I'll give him respect for that.

I 150% agree with you. Eric (and I don't know him peronally) has always been a fair and honest judge with products, and has the first hand experience to explain otherwise...when many (aka: 98% of the net) do not.

Originally Posted by Def

I see cars have HG sealing issues all the time with Cometics personally, and honestly stock SR gaskets aren't half as horrible as you'd believe reading the dumbasses that detonate theirs to death on Nissan forums.

Stock HG are more than fine for 350-400 whp on a good tune. Issue is, most people have a 85% tune, and a MHG lasts long enough to not make the tune shittyness an issue until a few years down the road.

For 90% of the forum, stock HG on a good tune is plenty fine. THe rest of us already know better.

Originally Posted by rbs14kouki

my friend is runing a OEM head gasket on is sr20VET ... it was a 650whp at 28psi mustang dyno last week !!!
[/URL]

VE have factory metal head gasket.

[inopsey]

Originally Posted by Sileighty_85

so one guy's engine holds a little over stock power says it can take it and you side with him?

You already have the engine out and almost apart might as well install an Apexi H/G for an ease of mind.

i run a 3071 at 20 psi for the last year and half (over 12 000 km) with a stock head gasket. checked compression after a year(8000 km) and it was 153-147 across the board. i plan on building the whole engine when its time to open up the engine not just fortify the head.

[R33E8]

Originally Posted by Def

They're growing their consumer side of the business, and you can't expect F1 engine technology for a couple of hundred bucks on most components, but come on man, are you really trying to compare Cometic as an engineering company vs. Cosworth?


Eric Hsu seems to tell it like it is even if it goes against whatever is putting the bread on the table for him. I'll give him respect for that.


I see cars have HG sealing issues all the time with Cometics personally, and honestly stock SR gaskets aren't half as horrible as you'd believe reading the dumbasses that detonate theirs to death on Nissan forums.

Originally Posted by codyace

I'd love to know why you wouldn't trust a company who still creates F1 level parts, still creates the best stuff for the most current 'tuner' cars, and still supports it's back catalog of stuff?

Cometic on an F1 car? Show me where.
.

Sheesh guys, I'm not saying Cometic is better than Cosworth. I wouldn't buy a Cometic head gasket either.. I just don't like comparisons made by companies that produce the part.. Obviously there will be some bias...

And for the record, I run a simple Fel-pro head gasket in my built KA running 20+ lb's of a boost with a gt35r... Whether or not Cosworth is a good brand is irrelevant to me since they don't make parts for any engine I have or that I'm interested in.. (KA, 2JZ, or LS1)..

[Def]

Originally Posted by R33E8

Sheesh guys, I'm not saying Cometic is better than Cosworth. I wouldn't buy a Cometic head gasket either.. I just don't like comparisons made by companies that produce the part.. Obviously there will be some bias...

And for the record, I run a simple Fel-pro head gasket in my built KA running 20+ lb's of a boost with a gt35r... Whether or not Cosworth is a good brand is irrelevant to me since they don't make parts for any engine I have or that I'm interested in.. (KA, 2JZ, or LS1)..

Then why talk about how they're a "different company than their glory days?" I'd say if anything, they're giving the most support to end users modifying street cars they've ever given.


You're trying to make it seem like we're putting words in your mouth, but you're the one taking a jab at their integrity as a company putting out quality products.

[R33E8]

Originally Posted by Def

Then why talk about how they're a "different company than their glory days?" I'd say if anything, they're giving the most support to end users modifying street cars they've ever given.


You're trying to make it seem like we're putting words in your mouth, but you're the one taking a jab at their integrity as a company putting out quality products.

I'm not saying they don't make quality products. I just don't trust comparisons from companies trying to promote their own products..

If I really wanted to take a jab at their integrity, I would talk about how they sold their engineering division to Audi more than 10 years ago, or how the entire company was sold I don't know how many times, or how a few years back nobody even wanted in them in F1..

But once again, I don't think they are a bad company, I just don't think they are as good as they used to be.. I believe they do a lot more R&D than a lot of these stupid knockoff and "JDM tyte" companies nowadays. But like I said before, I don't trust comparisons from companies trying to promote their own products... It's so easy to skew the results to make your stuff look better if no third party no involved...

And why are you guys getting so worked up about this? It's just my opinion and point of view.. I could be dead wrong and they could better than ever now.. If I'm wrong about anything let me know, I like learning new things..

[word sux]

cosworth is the way to go

[cotbu]

This sounds like the jury deliberation in the Casey Anthony trial. OK you lied to the police!

cosworth is the way to go