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I supported Toymods
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Central Coast
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May 2002
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7MGTE MHG & CHG q's
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Mon, 05 May 2003 07:33
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I know many of these questions may have been asked before, but I had a quick search but couldn't find much.
Anyways, I have a MZ20 Soarer with 7MGTE and the Head Gasket is on its way out, it hasn't completely gone yet, but under boost it is leaking.
I have been waiting for nearly a month for Toyota Penrith to bring in their MHG's, but for the last 3 weeks they keep telling me that they are in customs. I really want my car back by the end of the month, hopefully.
I have been reading up through performance forums, and supra forums, that you don't NEED to o-ring the block for a copper head gasket. If I remember correctly, there is a place in Australia that makes Copper head gaskets?
What are the advantages/disadvantages of having a copper one as opposed to a metal one?
Next question, I have purchased some ARP head studs. I have helped a friend fit them to his MZ20, but we firstly had to sit the head on the block, then screw the studs in, I have read elsewhere that the block should be removed to fit the stud kit. I was sure that there was ARP head bolts?
Can someone please shed some light on my worries?! 
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Location:
Brisbane
Registered:
May 2002
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 07:40
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Last time I checked, copper is a metal. Most people are referring to copper when they say "metal head gasket". There are other types of MHG's (eg steel) but copper is by far the most common.
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 07:44
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This place also makes metal gaskets for a good price I have been told http://www.ridgecrest.com.au/
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 07:45
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Umm ok I am definently confused now. I have read about people getting Copper Head Gaskets from down south somewhere? And they also mention metal Head Gaskets, but as if they are 2 different items?
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 07:49
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Thats the place. Thanks Cool1 !!
I have it book marked now 
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 07:52
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No problem
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Location:
Gold Coast
Registered:
May 2002
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 09:01
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Everyone I knows that uses a Copper headgasket has o-ringed the head and/or block.
You don't need to do this on a Steel Shim Type Gasket like a HK$ item.
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Location:
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 09:14
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errrr norbie, yes, a metal head gasket does descriptively include 'copper' but im pretty sure when ppl talk about mhg's in general, they mean a multi layer steel or similar etc... not copper.
theres NO WAY i would run a copper head gasket without o-rining the block (or head). copper is soft, malleable (sp?), and theres absolutely nothing stopping a copper hg from blowing (unless its oringed).
options that i would consider OTHER than say a HKS mhg (which i too am waiting for from penrith toyota!) is a) a custom composite material gasket with individual steel fire rings installed - about $300 from an engine builder i know. and b) fel pro duraseal head gasket with a stainless steel compressable fire ring inbuilt (like o-rining) not sure on price.
dont just do a copper h/g!!!
cheers
ed
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 09:20
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Ok can someone explain O-ringing? Possibly show some pictures? Or should I start another thread?
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Location:
Lost in the K hole
Registered:
May 2002
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 09:38
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o rining - basically you machine a reciever groove into the surface of the either the head or the block (or both) around each cyl. in this reciever groove sits a steel ring, whos thickness is more than the depth of the groove. when you install these with a copper head gasket, the ring is pressed into the copper, and produces a VERY high clamping pressure around each cyl, thus providing a high quality, tought to blow, seal.
without an o ring - copper is too soft to withstand the pressures of the combustion chamber etc, and simply dstorts and blows
ed
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 09:41
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Ahh ok. Fairly simple 
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Location:
Lost in the K hole
Registered:
May 2002
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 09:42
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note the circular grooves around each of the comb chambers
ed
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 09:47
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Yep thats very clear.
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Location:
Brisbane, QLD
Registered:
February 2003
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 14:30
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Are there any side effects to o ringing? How much does it cost
Is it really worth o ringing + copper head gasket
Or just going with a steel shim type HG?
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Location:
Central Coast, NSW
Registered:
May 2002
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 22:46
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I chose to go with the HKS metal shimm type gasket as i really didn't feel like taking the block out of the car without needing to!
Dan you should go for the studs as they provide a better result than bolts - there are two points of tension instead of one! I don't see why the block would need to be removed to install them either...
Dan
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 23:37
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Thanks for clearing that up Ed, I thought it was a must for the o-ringing. Not that I knew exactly what it was, but eh, now I do 
Looks as if I am going to have to wait for Toyota 
Dan:
I read somewhere that they had to take the block out in order to install the studs. I don't see why they just didn't do what we did and sit the head on first, the install the studs?
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Location:
Central Coast, NSW
Registered:
May 2002
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 23:50
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Yahh
The only reason i can think of is that having the block removed from the engine bay it possibly flexes back to its normal position which would allow you to flatten it out when putting the head on?? Similar to machining the head surface... you need to remove it and make it totally flat when you machine it so that when you tighten it back down onto the head it can go back to its warped little ways 
Does that make sense?
It does to me! haha
Dan
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Mon, 05 May 2003 23:54
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Umm kinda...
Are you saying that, when the block is removed and machined it is perfectly flat, then when installed again, it warps due to the engine mounts, gearbox etc?
If torqued down to 80lb then that should pull the bugger to the same shape yer?
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Location:
Central Coast, NSW
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May 2002
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Re: 7MGTE MHG & CHG q's
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Tue, 06 May 2003 00:05
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thats exactly it!!
i know what i want to say but it just never seems to come out that way 
thats my theory anyway - because my block wasn't machined (didn't need it) i could leave it in the car. You should be in the same predicament as me, or an even better one as your OEM gasket hasn't blown yet!
Dan
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Tue, 06 May 2003 00:10
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Thats the plan, hopefully *fingers crossed*
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Tue, 06 May 2003 06:37
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Ok next dumm question 
Whats the difference between studs and bolts?
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I supported Toymods
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Registered:
May 2002
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Tue, 06 May 2003 06:53
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Thanks 
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Location:
North Sydney
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May 2002
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Re: 7MGTE MHG & CHG q's
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Tue, 06 May 2003 06:56
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Just on the down side for oringing a 7M head.
As you can see in the picture there is sweet FA room between the combustion chambers and oringing can if not done properly cause more dramas due to improper sealing.
That's the problem with 3litre straight 6's, there's not much room between cylinders and between 5 & 6 is where the headgasket will usually blow.
Hence another reason why GTR engines now only 2.6lt, and they were once 3lt. Same for 7mgt'e drop to 2.5lt in the 1j, too many issues with head gaskets leaking cause there's not enough clamping surface between combustion chambers and they end up blowing into each other.
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Location:
Central Coast, NSW
Registered:
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Re: 7MGTE MHG & CHG q's
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Tue, 06 May 2003 06:56
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Bolts tighten only from one end, Studs tighten from both ends making them slightly more efficient!
Dan
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Tue, 06 May 2003 07:02
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Woohoo just got off the phone to Toyota, not long now!!
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Location:
Lost in the K hole
Registered:
May 2002
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Re: 7MGTE MHG & CHG q's
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Tue, 06 May 2003 09:34
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| Danners wrote on Tue, 06 May 2003 16:56 |
Bolts tighten only from one end, Studs tighten from both ends making them slightly more efficient!
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what in god's name is that supposed to mean?
defys the laws of physics
ed
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Location:
Brisbane
Registered:
May 2002
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Re: 7MGTE MHG & CHG q's
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Tue, 06 May 2003 23:47
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| SUPRAGTE wrote on Tue, 06 May 2003 16:56 |
That's the problem with 3litre straight 6's, there's not much room between cylinders and between 5 & 6 is where the headgasket will usually blow.
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Eh? Not every 3 litre straight six has ridiculously small bore spacing! That's a problem specific to the 5M/6M/7M because it got bored too far (ie it was originally designed as a 2 litre engine).
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Wed, 07 May 2003 00:58
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And the GTR was always designed with the 2.6l capacity so it had the short stroke 
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Location:
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Re: 7MGTE MHG & CHG q's
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Wed, 07 May 2003 09:35
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But it was first designed as a 3.0L not a 2.6L.
RB30 = 3lt
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I supported Toymods
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Re: 7MGTE MHG & CHG q's
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Wed, 07 May 2003 09:47
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They were just RB series engines. They weren't designed for the GTR specifically, I think their only purpose was the VL Commodore and the R31 Skyline over here!
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Location:
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May 2002
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Re: 7MGTE MHG & CHG q's
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Wed, 07 May 2003 13:40
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Yup, GTR's never had an RB30 to my knowledge.
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