blown mhg? need to fix? how to:

[quake]

I wish the mkiii community would stop using the crappy cometic gasket then make a post about a blown gasket.


1. use the hks stopper.

2. resurface head and block as needed there should be no erosion around the cooling ports and no ring left around the combustion chambers from and old gasket.

3. lap both surfaces untill there are no finish marks (you will know when you do it)

4. measure head and block to see how much has been removed by you or previous owners.

5. spray it or not with copper spray it won't matter.

6. use arp studs

7. never make a post about a blown headgasket again




at the end of this all you have done is to update your 1980's design motor surfaces to newer technology. Even a crappy 05 corolla has this style gasket and surface finish.

 

[hvyman]

cometic is the same as titan and lots of people are making power with reliability with both. i dont get this thread.

 

[jdub]

I wish the mkiii community would stop using the crappy cometic gasket then make a post about a blown gasket.

1. use the hks stopper.

2. resurface head and block as needed there should be no erosion around the cooling ports and no ring left around the combustion chambers from and old gasket.

3. lap both surfaces untill there are no finish marks (you will know when you do it)

4. measure head and block to see how much has been removed by you or previous owners.

5. spray it or not with copper spray it won't matter.

6. use arp studs

7. never make a post about a blown headgasket again

at the end of this all you have done is to update your 1980's design motor surfaces to newer technology. Even a crappy 05 corolla has this style gasket and surface finish.

The Cometic is not "crappy"...it does depend on proper block/head prep like any MHG. 90% of the posts you're referring to are the direct result of improper prep.

Copper spray will attack the viton on a MHG...the chemicals in them have a known interaction with viton. Use it if you wish, but experience does not trump the facts in this case.
IMO, it's an extremely stupid move.

 

[BrandonW]

i was not able to have my block lapped but it did come out to be pretty smooth, ra 23 and my head i got from dm that has a ra of 8 so i hope and think i will be ok because i did get the hks 2.0mm stopper gasket

if not i'll blame gaboonviper

 

[ForcedTorque]

^I believe the RA specs will be specified in your instructions with whatever head gasket you use. The size of that head gasket should be determined by the measurements above to find how much material has been removed. Don't just assume that 2.0MM sounds cool because somebody else used it. Changes in thicknesses from stock will affect your compression ratio.

I wouldn't take the word of just one member. Let goon off the hook.:biglaugh:

 

[BrandonW]

haha no i did all the right stuff it rounded off to be a 1.6 but with a 86 bore so the options for
cometic was 1.5 or jump to the 2.0
hks 2.0 bead or stopper
greddy didn't have 86 bore but i believe i could have used 85 and if so it was a 1.5 or jump to the 2.0 again

and also because of the combination of upping the boost down the road and the fact that i wanted to use the stopper i went with it

i also read this
http://www.supramania.com/forums/showpost.php?p=350539&postcount=9

HKS Stopper type - best there is, also the most expensive. 30 RA spec. Crank the boost to your hearts content (you can still blow the motor though) <edit IJ 100% correct on this >

HKS, Titan, Greddy Bead type - Very good, also requires a 30 RA. 20+ psi easily

Cometic - Bead type, also very good. Big difference is the RA spec is 50. 20+ psi easily

mostly what i was pointing out in that link so i should be fine and when i say i'll blame gaboon im kidding and because he helped me out by measuring my stuff and checking the ra at his work (which i appreciate)

 

[Zumtizzle]

I'm going to question

#1 and #5.

Edit: Too Late, Thanks John.

 

[quake]

The Cometic is not "crappy"...it does depend on proper block/head prep like any MHG. 90% of the posts you're referring to are the direct result of improper prep.

Copper spray will attack the viton on a MHG...the chemicals in them have a known interaction with viton. Use it if you wish, but experience does not trump the facts in this case.
IMO, it's an extremely stupid move.

1. cometic is crappy as i stated you only have 3 layers with no fire ring to bite into.

2. copper works fine as i use it on my over priced 400 dollar gasket and boost over 19psi daily. I have used it more than once and never have a problem.

 

[toyotanos]

My cometic has 4 layers (2.0mm, 84mm)

Also, spraying copper spray on a brand new gasket is a bad idea. It's fine if you spray a undamaged, used, and cleaned MHG with a copper spray, but never new.

 

[jdub]

1. cometic is crappy as i stated you only have 3 layers with no fire ring to bite into.

2. copper works fine as i use it on my over priced 400 dollar gasket and boost over 19psi daily. I have used it more than once and never have a problem.

1) I don't know what you're smoking, but it must be good. All MHG's have a fire ring around the cylinder, including the Cometic...they are not all copper though (and don't have to be). Also, more layers is not necessarily better, it depends on the design...did you sleep through those classes in tech school? Allow me to provide a review:
http://www.supramania.com/forums/showpost.php?p=216396&postcount=5

Cometic, Greddy, and HKS all produce MHG's with the same bead design to seal the combustion chamber...I guess all of these are crap, huh? The stopper takes it a step further and adds a grommet to the bead, providing a more sturdy seal. The choice depends on the intended use and on proper prep. You cannot make a blanket statement like you did...it's way wrong.

2) Well, people can do what they want...after all, it's not my car. They can listen to you (and your mechanic experience) or they can take a look at the sticky in this section that contains hard data on the chemicals, published by the companies that make the products. I wonder who is right? The mechanic or the chemical engineer that formulated the product.

Of course, most the mechanics I know want you to change your oil every 3000 miles too

 

[quake]

My cometic has 4 layers (2.0mm, 84mm)

Also, spraying copper spray on a brand new gasket is a bad idea. It's fine if you spray a undamaged, used, and cleaned MHG with a copper spray, but never new.

cometic has 3 layers a 1 shim and a top and bottom layer makes 3

 

[jetjock]

Crack me up. I remember when there were no MHGs. We'd use stainless steel wire to seal the cylinders. Now we're arguing about what works...

 

[jdub]

Crack me up. I remember when there were no MHGs. We'd use stainless steel wire to seal the cylinders. Now we're arguing about what works...

Exactly! If a guy wants the best, the HKS Stopper is it. But it's not the only one that will work (among others)

 

[quake]

1) I don't know what you're smoking, but it must be good. All MHG's have a fire ring around the cylinder, including the Cometic...they are not all copper though (and don't have to be). Also, more layers is not necessarily better, it depends on the design...did you sleep through those classes in tech school? Allow me to provide a review:
http://www.supramania.com/forums/showpost.php?p=216396&postcount=5

Cometic, Greddy, and HKS all produce MHG's with the same bead design to seal the combustion chamber...I guess all of these are crap, huh? The stopper takes it a step further and adds a grommet to the bead, providing a more sturdy seal. The choice depends on the intended use and on proper prep. You cannot make a blanket statement like you did...it's way wrong.

2) Well, people can do what they want...after all, it's not my car. They can listen to you (and your mechanic experience) or they can take a look at the sticky in this section that contains hard data on the chemicals, published by the companies that make the products. I wonder who is right? The mechanic or the chemical engineer that formulated the product.

Of course, most the mechanics I know want you to change your oil every 3000 miles too

lol you are funny, first off i'm not a mechanic. Second you will be the last person on the planet to teach me shit.

When i said fire ring i meant the 4th layer that puts a (stopper ring) around each cyl. The others that don't have it allow threads like this to go on forever. If 1-5 is followed properly you wont have a problem. I could go outside tear off my stopper put on my cometic and blow it. I feel it is crappy because at some point you can increase cyl pressure to the point of pushing past the crappy bead seal.

hks offers 3 gaskets stopper being the best.

toyota no longer uses a paper gasket.

the mkiv uses a stopper style gasket this is why you see them pushing a stock motor with much bigger turbos and much more cyl press


by the way i don't deal in theory as there is alot of it on supramania i deal with what works i have put on gaskets dry i have sprayed gaskets and it works fine on hks and cometic. Anyone with questions pm me as the laptop ninja is all over this thread

 

[jdub]

lol you are funny, first off i'm not a mechanic. Second you will be the last person on the planet to teach me shit.

When i said fire ring i meant the 4th layer that puts a (stopper ring) around each cyl. The others that don't have it allow threads like this to go on forever. If 1-5 is followed properly you wont have a problem. I could go outside tear off my stopper put on my cometic and blow it. I feel it is crappy because at some point you can increase cyl pressure to the point of pushing past the crappy bead seal.

hks offers 3 gaskets stopper being the best.

toyota no longer uses a paper gasket.

the mkiv uses a stopper style gasket this is why you see them pushing a stock motor with much bigger turbos and much more cyl press


by the way i don't deal in theory as there is alot of it on supramania i deal with what works i have put on gaskets dry i have sprayed gaskets and it works fine on hks and cometic. Anyone with questions pm me as the laptop ninja is all over this thread

The most powerful ability is theory + knowledge + experience (common sense)...I'm still being taught. Looks like you are done with all that...pity, a guy your age should have figured it out by now. Learned long ago being closed/single minded is a rather bad thing. Do what you like Mr Toyota Tech...I'm sure your PM box will be full shortly.

BTW - I wasn't trying to "teach" you anything...that post was to correct your rather lame discription of how the various MHG's seal. I only try to teach those willing to learn.

 

[quake]

Crack me up. I remember when there were no MHGs. We'd use stainless steel wire to seal the cylinders. Now we're arguing about what works...

it has to be this way as the mkiii is now known for blowing gaskets lol. Now if the head was 5" shorter with the same amount of head bolts it would seal better, but it's not so we have the stopper.

 

[jetjock]

:shrug: Mine never blew it's HG and those that do don't seem to have anything to do with gasket brand. I'm not disputing what you've seen but your sample rate is tiny. The collective experience of the community indicates you're wrong.

 

[jdub]

:shrug: Mine never blew it's HG and those that do don't seem to have anything to do with gasket brand. I'm not disputing what you've seen but your sample rate is tiny. The collective experience of the community indicates you're wrong.

Not to mention a small matter called "chemistry"...of course all that is pure "theory". Breaking News!!! The world is flat

 

[sparkplug619]

1 track mind

 

[quake]

1 track mind

yeah make power, keep the same gasket in the car and never make a post of blowing one that is my one track