Cometic Head Gaskets??

[4WARNED]

Well, my 88 Mazda GTX has decided it needs a new head gasket.....
Does anyone know of a local supplier that can supply a COMETIC head gasket? That's the brand name.....CMC4122 80mm 0.040" if that means anything to a vendor out there.....same part as the 1.6L Miata engine...

Thanks in advance....

[AllGoNoShow]

Why wouldn't you just go with OEM?

[Daxin]

I'm pretty sure Mopaq sells Cometic Head Gaskets. If not, you can get Tunerworks to order you one.

[djfob]

Speedtech and Custumauto can get them

[4WARNED]

Thanks guys!!

I will check with Speedtech and custumauto..

The OEM gaskets won't hold up to higher boost levels (according to almost everyone who has boosted a Miata along with the GTX junkies.....)...

[rage2]

In most cases I've seen, it's the headstuds that needs upgrading, not the headgasket. A properly tuned motor should not damage an OEM headgasket that's installed properly.

[4WARNED]

If the problem is more severe than my headgasket, i'm "hoping" for a full rebuild anyways....
I should check with Illeagle on here.....
He went through the exact same thing with the head on his 323GT.....

[AllGoNoShow]

What rage2 + the fact that legendboy has done MANY turbo applications, rage2 tunes them, they both say to use OEM headgaskets with ARP headstuds.

[heavyD]

When I got my 4G63 rebuilt with forged internals and ARP fasteners I opted for a Cometic but it wouldn't seal. The mating surfaces have to be decked mirror smooth or it won't seal. Stuck the OEM headgasket in and no problems.

[Dirty_SOHC]

I've had my cometic gasket for over 2 years now. I have no issues with the headasket, knock on wood

[90awdwagovan.]

Originally posted by 4WARNED

The OEM gaskets won't hold up to higher boost levels (according to almost everyone who has boosted a Miata along with the GTX junkies.....)...

Originally posted by AllGoNoShow
What rage2 + the fact that legendboy has done MANY turbo applications, rage2 tunes them, they both say to use OEM headgaskets with ARP headstuds.

uhuh

you can't compare honda to mazda, (or engine to enginefor that matter)

[illeagle]

Yah, i went with the OEM gasket, but then again i was only pushing 11 psi. I wanted a cometic gasket but that ment ordering through the net...and i hate that, plus i diden't have the time to wait... road race engineering was where i was gonna get my gasket from.
http://www.roadraceengineering.com/

[AllGoNoShow]

Originally posted by 90awdwagovan.




uhuh

you can't compare honda to mazda, (or engine to enginefor that matter)

Heya tubgirl cock, I'm not comparing Honda to Mazda, I'm comparing what people use, no matter what car, to what other people use, OEM is what many many people use, sure alot also use non-OEM headgaskets but tons of tuners around the planet use OEM. I'm just helping him possibly save himself hassles in the long run, better headbolts + OEM gasket will turn out better then normal headbolts and non-OEM gasket.

Go look at some more tubgirl....

[90awdwagovan.]

Originally posted by AllGoNoShow


Heya tubgirl cock, I'm not comparing Honda to Mazda, I'm comparing what people use, no matter what car, to what other people use, OEM is what many many people use, sure alot also use non-OEM headgaskets but tons of tuners around the planet use OEM. I'm just helping him possibly save himself hassles in the long run, better headbolts + OEM gasket will turn out better then normal headbolts and non-OEM gasket.

Go look at some more tubgirl....

Buddy please.

Do you not understand how retarded your statements are.

pay attention here... you (a kid in high school) is going to advise someone to use a stock head gasket and ARPs on a MAZDA because a couple people said to use them on a HONDA? Has bandwagon jumping gotten this bad?

What, you have maybe 3 years in the field? I'm sure you have witnessed personally many applications on a wide variety of cars, made by an assortment of manufactures demonstrating varying amounts of power. I'm sure you completey understand the advantages and disadvantages to altering the static compression ratio. With out a doubt you understand the differences between open deck and closed deck design, headgasket construction whether it be 1 layer, or even 4 layer construction, and how different construction materials affect the heat conducting properties. Don't forget different manufactures techniques on designing head STUDS and the various materials and ductilities used.

hahaha, regardless, even if you knew all of that it would be instantly nullified if you had never examined the difference between the factory gasket and aftermarket one, or tested the limits of the engine.

Come one man, it's obvious you have no idea what you are talking about, you even give conflicting statements.... '...OEM is what many many people use, sure alot also use non-OEM headgaskets...'

so I'm confused, if alot use oem, and alot use non oem... then which one is it? how can you recommend either? do you know the specifics of his car, his application, his power goal, the cylinder head pressures and how they affect certain weak portions of the stock factory head gasket? (see above)

better head bolts + OEM gasket will turn out better then normal headbolts and non-OEM gasket.

Where'd you pull this little tidbit of information? Dude, what I'm trying to say is that everything is application specific. There is no need for anymore 16 year olds running around spreading generalities and unspecifics.

I'll have you know, that factory honda head studs (yes they are head studs, not head bolts) are torque teel, which means they stretch after the first time they are torqued. This is why they are recommended to be torqued once.... but..... guess what....

so are ARPs!!! The only difference is ARP supplies the bolt stretch numbers while honda doesn't. This enables you the ability to properly stretch the studs next you time you install them.
You are right on one thing though, honda owners did get blessed with some very capable head gaskets...

Are mazdas the same? can you honestly say?


and I’m glad you enjoyed tubgirl....

[rage2]

It's not just Hondas, I've seen it done on MANY applications, VW's, DSMs, even my Porsche. On my 944 turbo, I've ran OEM HG forever, even with my 28psi 460whp runs on the roadcourse. No problems. What people say about cometic HG's are true... you have to have a perfect surface or it wont mate properly. I actually switched to a cometic HG on my 944 turbo right now, and it's seeping lightly.

[legendboy]

Originally posted by 90awdwagovan.
I'll have you know, that factory honda head studs (yes they are head studs, not head bolts) are torque teel, which means they stretch after the first time they are torqued. This is why they are recommended to be torqued once.... but..... guess what....

so are ARPs!!! The only difference is ARP supplies the bolt stretch numbers while honda doesn't. This enables you the ability to properly stretch the studs next you time you install them.
You are right on one thing though, honda owners did get blessed with some very capable head gaskets...

I'll have you know that arp fasteners have a much higher yield strength than pretty much any oem fastener. Oem honda head bolts are weak period.

Also, you had better explain to me "This enables you the ability to properly stretch the studs next you time you install them."

If you re read your statement in the context of the paragraph it doesn't make any sense. There is no calculation to equate how much a bolt is permanently stretched to what it should be torqued to in that state of damage. Either a stud is in spec or its out of spec and should be replaced. This is also only good if you have measured the fastener brand new with a micrometer.

Also, in the context of head studs and bolts, we pre-load or stretch by torquing them with a torque wrench. We have no way to measure the stretch on these fasteners while installing them.

[AllGoNoShow]

Your right 90awd, I don't know some of the specifics, I'll admit it, sure of that shit makes no sense to me, at all, some of it does, and some of it I know, that isn't the point.

I'm not spreading shit around, majority of the time if I know something or have looked into it, I will post about it, if I'm pulling shit off the top of my head then I'm not going to post about it as I know I'd have a chance of being wrong and spreading incorrect information.

On the other hand, look who has posted RIGHT after you before I even woke up about the subject, I'm learning still, I'm learning from them and others around the world, but I would much rather learn from someone like legendboy or rage who has respect for people still in high school, high school means shit all in the terms of knowledge, I'm not saying i know more then you but you are being childish using that as your defence.


Ok so maybe its a Honda only thing, and not a Mazda, I was suggesting from what I know, maybe I should have made it more clear its that way for Honda, maybe it is that way for Mazda aswell but I am unsure, would that have made you happy?

EDIT: Forgot to mention.... If your going to be bringing age into this matter (high school) then you must be either younger or the same age with the way you treat people willing to learn, for example sending useless PM's linked to even more useless places like tubgirl for people who are serious about learning. I wasn't asking for a leakdown tester before to just use it and figure it out, it would help me diagnose my problem, so why would you screw around with someone who is learning, now you would be the one spreading useless tidbits of information around.....

[90awdwagovan.]

Originally posted by legendboy


I'll have you know that arp fasteners have a much higher yield strength than pretty much any oem fastener. Oem honda head bolts are weak period.

I never said anything doubting that.... And I'll go as far as to agree with you too.

Also, you had better explain to me "This enables you the ability to properly stretch the studs next you time you install them."

If you re read your statement in the context of the paragraph it doesn't make any sense. There is no calculation to equate how much a bolt is permanently stretched to what it should be torqued to in that state of damage. Either a stud is in spec or its out of spec and should be replaced. This is also only good if you have measured the fastener brand new with a micrometer.

I was talking about the differences between Torque/angle tighten, and Torque to yeild specs. A failure to proof read on my part, yes, it makes no sense what so ever. Once a a bolt is torqued past its yield point it will not return to its original length.

Also, in the context of head studs and bolts, we pre-load or stretch by torquing them with a torque wrench. We have no way to measure the stretch on these fasteners while installing them.

Knowing the thread size and pitch, it is easy to determine just how many thousandths of an inch the bolt [of a known diameter and material] will stretch if it is turned a certain number of degrees. The angle tightening method is a way of more accurately stretching the bolt. Reports that I have read indicate a accuracy variation in clamping force applied using the angle tightening method to be in the 15% range...a considerable improvement over the "Torque" method(variations as much as 35%)

[legendboy]

Originally posted by 90awdwagovan.

Knowing the thread size and pitch, it is easy to determine just how many thousandths of an inch the bolt [of a known diameter and material] will stretch if it is turned a certain number of degrees. The angle tightening method is a way of more accurately stretching the bolt. Reports that I have read indicate a accuracy variation in clamping force applied using the angle tightening method to be in the 15% range...a considerable improvement over the "Torque" method(variations as much as 35%)

http://www.arp-bolts.com/pages/tech/fastener.html
ARP® has conducted extensive evaluations of the torque angle method. We have concluded that, for our purposes, it is suitable only when individually calibrated for each installation.

Simple calculation of bolt stretch based on thread pitch is not accurate. No material is incompressible. When a bolt or a stud is pre-loaded or stretched, the components being clamped compress to some small extent. When we are looking for bolt stretch of only a few thousandths of an inch, the amount of clamped material compression becomes a very real factor. Our investigation has proven that installed stretch is dependent, not only on the pitch of the thread and the degree of rotation, but also on the amount of compression of the clamped components, the length of the male fastener, the amount of engaged thread, the type of lubrication and the number of times that the fastener has been cycled.

Torque wrench for headstuds

[90awdwagovan.]

Originally posted by legendboy


'ARP® has conducted extensive evaluations of the torque angle method. We have concluded that, for our purposes, it is suitable only when individually calibrated for each installation.'


Torque wrench for headstuds

again, It's application specific, which is the whole point I was trying to push