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Discussion Starter · #1 ·
ok i got a 4layer metal headgasket i was told i could take a layer off and get more compresion but i would have to drill out the rivets holdin it together. my questions is , is this true and will it work and how many layers can i take off before i hit the valves and still seal the head properly....thanx in advance
 

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The answer to all your questions is "don't bother with doing it." The 10th of a point increase in compression isn't worth the effort. If you really want a compression increase, pull the head, have it "O" ringed and that will eliminate the head gasket all together and give you a noticeable increase your compression. The trouble with delaminating your gasket is it will not seal properly if you do it.
 

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+2

just have the head milled a bit!

OR, get some better pistons they make 11:1's I've seen, or does it have to sound stock?
 

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racerboy said:
How can different pistons make it sound different?
I agree, there will be no change in sound with an increase in compression. Changing the cam duration and/or lift can change the exhaust note, but not compression.
 

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ok I always thought the higher the compression the louder and more explosive the motor would sound. ok then slap some high comp pistons in that bad boy!
 

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sounds good!
 

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And you cant use replacement pistons that have domes, or lack the reliefs for the valves. Between the top of the stock pistons, and the bottom of the stock head there is about about .030" as it is. "Squish height".

One of the things I LIKE about my Escort is that its a non-interference engine, and doesnt need a knock sensor either.
 

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denisond: the mazda BP's are non interference and have the valve reliefs, you can get 11:1 pistons and it's still non interference from what I can tell there.

milling the head should be done if you take it off anyway, it does give just a tiny hit more compression which won't really give you more HP, you might get 1 more hp, idk!

oh and BP's don't have knock sensors that I've ever seen.

hey dirttrack do a K code hybrid vaf??? like the B code but easier to find, course it doesn't hook into that black box the same :S bigger won't fit inside of the 3 inch hole, it's 3 1/4"
 

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Discussion Starter · #14 ·
i got b code maf rx7, cut out the wall inside of the intake manifold on cyl 2 to get more direct air flow, also did ex cam swap, my car has to look stock so im tring to get as much power out of my bp with little cost and look stock. i heard that those 11.1 pistons have to have a aftermarket comp or something cauise they will \gunk up is that true?
 

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New stage 2 or 3 clutch and light flywheel could run $600+. In your application, the light flywheel might be worth it, but since your are racing on a dirt course, I wouldn't spend a lot on a clutch designed for drag racing and would most likely cause chatter.
 

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Escort92Man said:
denisond:
milling the head should be done if you take it off anyway, it does give just a tiny hit more compression which won't really give you more HP, you might get 1 more hp, idk!
Hey ... what ya smoking over on that side of the planet?

You won't get 0.0001 hp gain from a shaved head.

Wesco can make pistons that will give 11.5:1 compression and that will give you about 3 Hp and require you always run 97 octane gas. Should only cost ~ $500 plus the rebuild to install them ... not bad! :wink:
 

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head milling

If you do mill thead & it goes over .010, you mught want to use the extra shim gasket or head saver they sell. I did, and didnt kno anything about it until a female parts attendant at O Rileys told me about it.
Steve
 

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Well you would barely notice taking 5 thou off it. I had 40 thou off. CR is just shy of 11 I think. Make sure you take enough off the locator pegs too or you wont get it sealed.
 
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