head gasket questions

mercuryfreak200

?Which parents?
ok here is the scoop i was supposed to get my motor back today didn't happen apparently it has blown a head gasket at some point in its life cause when i pulled it apart it had a metal head gasket in stead of the normal one i usually find. so i'm boreing it 40 over to get rid of the pits and so rings will seal (hope thats the right way to go) now when i put this together i'm not using the origanal head bolts i bought brand new ones from toyota (couldn't afford arp right now lost my job) i'm deffanantly going to use a metal head gasket but what should i toruqe it to i don't trust the book on this cause i know these are nutorious for bhgs so little help or direction thanks
 

msimsi10

Member
Jun 28, 2009
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Novi, MI
mercuryfreak200;1501565 said:
is that whats recommended by toyota

Toyota specs is 58 ft-lb but them using a MHG some on the forum would recommend going as high as 95 ft-lb I torque to around 85 ft-lb
 

BrandonW

New Member
Jun 25, 2007
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mercuryfreak200;1501591 said:
so any where between 70 to 100 ftpds is where it needs to be even without the arp bolts

no

if using toyota head bolts 72ft/lbs if using arp studs you can go as high as 90ft/lbs using moly lube but only follow what the instructions tell you there are older and newer versions

quoted from jdub
The newer studs have a higher tensile strength, hence the higher torque. Bottom line is it depends on which version you have...use the spec on the sheet in the box. If they are used studs, I'd go with 80 ft/lbs using moly.

ARP Bolts are limited to 75 ft/lbs on an aluminum head.
 
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hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
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no 100 is way too much even with arps. stock is 58 butis too low. use 72 with stock head bolts. arps come with a torque sheet thats says what to torque to. this is all speculation but i have heard of arps saying that the new bolts come with 90 ft lbs torques sheets but all the old ones say 80. my stock bolts have been torqued to 85 which is too much but its too late to change it.(PO torqued it to there.)
 

kamikazemkiii

Active Member
Mar 21, 2009
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North Carolina
Are you sure .20 wont get the pits out? Has your head, block, and timing cover been decked? What size MHG are you planning on running? All these things are critical thats why im asking.

Also id sell the head bolts you bought, toyota uses streach bolts ive been told.
 

gofastgeorge

Banned
Jan 24, 2008
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Don't exceed 80 ft/lbs with stock bolts. :aigo:
They permanently stretch if taken to 85 ft/lbs (exceeding their yeild strength).
72-75 is a good number.
 

mercuryfreak200

?Which parents?
well i idk about the head gasket size never thought about that but then both the head and the block are straight its been done to it be fore and the pits are pretty bad you could almost move in to a couple of them the machine shop thought it might make .30 but i just wanted to make vsure i got a good seal for the rings don't like blow by... but the head gasket thickness matters thats new to me but then im a old school mechanic so this is my first sports car but i want it done right
 

kamikazemkiii

Active Member
Mar 21, 2009
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North Carolina
Well also make sure you have the timing plate decked aswell or the mhg wont seal correctly, you may already know but the stock bore size is 83mm but if u get .40 over then ur headgasket bore should be 84mm. and i wouldnt get anything thinner than a 1.4 mm headgasket. depending on how much has been taken off, and the pistons you choose should play a part in the HG selection thickness. Hope that helps, just throwing it out.