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Location:
Bundaberg, Qld.
Registered:
May 2002
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compression ratio
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Wed, 17 September 2003 11:46
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 i just read this on another forum...
for every .1mm of headgasket thickness either way it is .1 or a compression ratio
so if my 4agte now has a 3mm +/- headgasket with 9.4:1 pistons i an running a approximate 7.6:1 c/r?
mmm.. i need to whip the head off and put the normal one back on... 
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Location:
MACKAY
Registered:
May 2002
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Re: compression ratio
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Wed, 17 September 2003 13:01
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A 3mm gasket will give you more like 7.9 and a 2mm will give 8.6 .
Trevor
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Location:
Perth
Registered:
September 2002
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Re: compression ratio
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Wed, 17 September 2003 13:46
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I think it varies on different motors but I have researched and found that .1mm is .1 c/r on 4ag's yes..
7.6 is damn low 
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Location:
Perth
Registered:
September 2002
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Re: compression ratio
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Wed, 17 September 2003 13:48
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And where the hell did you get a 3mm gasket from? haha 
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: compression ratio
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Wed, 17 September 2003 14:55
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erm .. that sounds like crap.
logically thinking, it would depend on the initial dimentions of the engine. the shorter the combustion chamber, the more effect the head gasket would have.
of course, logic doesn't always translate well into reality
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Location:
Perth
Registered:
September 2002
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Re: compression ratio
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Wed, 17 September 2003 15:01
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Yeah like i said it depends on different motors..
Put it this way
Stock GZE HG is 1.2mm
HKS make different sized gaskets and advertise that:
1.6mm drops it .4cr
2mm drops is .8
So wouldnt that just reinforce the above statement?
I trust HKS...
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Location:
Bundaberg, Qld.
Registered:
May 2002
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Location:
Perth
Registered:
September 2002
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Re: compression ratio
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Thu, 18 September 2003 04:19
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Yeah i agree
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Location:
Brisbane
Registered:
May 2002
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Re: compression ratio
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Thu, 18 September 2003 06:39
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I'd just like to point out that this is a very poor way of decompressing an engine (ie using a thick headgasket or decompression plate). Yes it decreases the compression ratio, but it also makes the quench areas less effective - and that can make the engine more prone to detonation than it had been!
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Location:
Lost in the K hole
Registered:
May 2002
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Re: compression ratio
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Thu, 18 September 2003 06:50
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what norbie said
just replace 'very' with 'excedingly'
(when are we going on a date dude? - sick of backing you up and getting no love)
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: compression ratio
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Thu, 18 September 2003 06:52
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and what happened to all the sweet words you said to me last night?
You told me I was the only one 
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Location:
Bundaberg, Qld.
Registered:
May 2002
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Re: compression ratio
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Thu, 18 September 2003 08:21
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| Norbie wrote on Thu, 18 September 2003 16:39 |
I'd just like to point out that this is a very poor way of decompressing an engine (ie using a thick headgasket or decompression plate). Yes it decreases the compression ratio, but it also makes the quench areas less effective - and that can make the engine more prone to detonation than it had been!
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yes i agree, just when i rebuilt it $$ was very tight (still is).
and this is just basically a intrim engine until i rebuild my original gze based 4agte or buy another complete 4agze engine.
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Location:
Brisbane
Registered:
May 2002
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Re: compression ratio
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Thu, 18 September 2003 14:10
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You know I love you Ed. Even if you are still tinkering with those clunky old 7M's.
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: compression ratio
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Sat, 20 September 2003 07:57
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erm... you do know how cheap forged/coated GZE pistons are don't you? They are 8.9:1 ratio and nice and CHEAP at $400 new from Toyota.
Just a though
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Location:
Bundaberg, Qld.
Registered:
May 2002
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Re: compression ratio
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Sun, 21 September 2003 10:54
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| THE WITZL wrote on Sat, 20 September 2003 17:57 |
erm... you do know how cheap forged/coated GZE pistons are don't you? They are 8.9:1 ratio and nice and CHEAP at $400 new from Toyota.
Just a though
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yes i do, you have said in many post now. i think we all get the idea!!!!!!!
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