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Old 05-16-2007, 09:21 PM   #1
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Default *Head gasket questions

Does anyone know how thick the stock head gasket is on a 1.8l?

Last edited by RusMan; 05-17-2007 at 09:40 PM.
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Old 05-17-2007, 09:39 PM   #2
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You guys suck

Anyway I found out it's 1mm. One more question though, how much will my compression change if I go with a 2mm head gasket? I have 9:1 pistons
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Old 05-17-2007, 09:59 PM   #3
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Why do you want a 2mm gasket?
9:1 will be low enough compression for the power you want, if you lower the compression anymore you're just robbing yourself of power.
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Old 05-17-2007, 10:01 PM   #4
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I don't really want to but I need a head gasket that will work with my 84.5mm bore (stock is 83) and the bigger bore gasket I found is 2mm thick. Do you think the stock gasket will work with that bore?
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Old 05-17-2007, 10:05 PM   #5
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I don't know if it will work or not but I do know that the 2mm that you're looking at isn't going to be that big a deal. For someone to tell you what your compression ratio is going to be they need to know all kind of specs for your pistons and if you have the block and head resurfaced all that changes your compression a miniscule amount as well. Either way, the slightly thicker gasket isn't going to hurt or benefit you enough to matter, atleast I don't think it will.
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Old 05-18-2007, 12:30 AM   #6
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Quote:
Originally Posted by cjernigan View Post
Why do you want a 2mm gasket?
9:1 will be low enough compression for the power you want, if you lower the compression anymore you're just robbing yourself of power.
you'll rob yourself of power off boost. In boost nothing changes in boost becuase you're still compressing the same amount of air.
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Old 05-18-2007, 03:36 AM   #7
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Alright, I didn't really want the 2mm gasket. I just went to the shop and measured the stock gasket and it's just fine with my pistons so I'll be just using that.
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Old 05-18-2007, 04:33 AM   #8
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Just over tighten the head bolts... voila 1 mm head gasket.

This isnt that hard, anyone know the clearance volume on the stock motor?

RusMan im dead tired, but we can figure this out later if you really want to know...
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Old 05-19-2007, 05:02 AM   #9
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Well from what I calculated with 1mm thicker head gasket the compression should drop to aproximately 8.3:1, but my calculations are as inaccurate as they can get, haha
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Old 05-19-2007, 05:40 AM   #10
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1mm is 1/85th of the stroke. Would that make a 5.29cc difference? (450cc/85=5.29cc) and (450cc/9.1=49.5cc) and (1/49.5*5.29=0.1) 49.5cc=1 and 5.29cc=0.1 Would it be 9.0:1?

I'm guessing here. =)
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Old 05-19-2007, 01:43 PM   #11
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Quote:
Originally Posted by lazzer408 View Post
1mm is 1/85th of the stroke. Would that make a 5.29cc difference? (450cc/85=5.29cc) and (450cc/9.1=49.5cc) and (1/49.5*5.29=0.1) 49.5cc=1 and 5.29cc=0.1 Would it be 9.0:1?

I'm guessing here. =)
To tell you the truth I have no idea what you just did but it doesn't look right to me for some reason, and FIY I have 9:1 pistons so that's the starting point
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Old 05-20-2007, 06:41 AM   #12
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Quote:
Originally Posted by RusMan View Post
To tell you the truth I have no idea what you just did but it doesn't look right to me for some reason, and FIY I have 9:1 pistons so that's the starting point
I was trying to figure out what 1mm was in relation to the stroke of the engine and if the 9:1 ratio is the relation between stroke length and combustion chamber volume then adding 1mm is adding like 5cc or something like that. It looked right when I did it. lol
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