Cosworth 4x4 Head Re-Torque
#1
Cosworth 4x4 Head Re-Torque
hi, the engine was rebuilt about 3000 miles ago it also had a brand new head. theres oil starting to seep out were the head meets the block.
what should i re torque the bolts to an do i have to loosen them before i do it?
also what order shuld they be done in start at the center and work your way out?
thanks
what should i re torque the bolts to an do i have to loosen them before i do it?
also what order shuld they be done in start at the center and work your way out?
thanks
#3
Bolts should be torqued in stages:
Stage 1: 45-50nm
Stage 2: +180 degrees
Stage 3: Check for 110nm
Leave overnight, and recheck for 110nm, just incase the head's lifted slightly.
If they've stretched and are now loose, you really should change them, they're useless after they've stretched, IMO.
Stage 1: 45-50nm
Stage 2: +180 degrees
Stage 3: Check for 110nm
Leave overnight, and recheck for 110nm, just incase the head's lifted slightly.
If they've stretched and are now loose, you really should change them, they're useless after they've stretched, IMO.
#4
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As tab said this will vary greatly depending on the bolts used.
I recently did the cylinder head on my cosworth with 10.9 grade head bolts (that most suppliers will tell you are genuine or as good as), I simply could not achieve the 180degree final stage. (considering i was using a two foot breaker bar it should have been easy)
So i checked the bolts afterwards to see how tight the 120degree that i managed to get them all to was and it maxed out my torque wrench which goes upto 140nm.
So I think it is safe to say the 10.9 grade bolts dont stretch anything like as much as genuine ford/cosworth bolts and if I had to use them again (which I wont) I would probably be looking to do a 90degree final turn and then once all settled check for 110nm on all bolts.
I recently did the cylinder head on my cosworth with 10.9 grade head bolts (that most suppliers will tell you are genuine or as good as), I simply could not achieve the 180degree final stage. (considering i was using a two foot breaker bar it should have been easy)
So i checked the bolts afterwards to see how tight the 120degree that i managed to get them all to was and it maxed out my torque wrench which goes upto 140nm.
So I think it is safe to say the 10.9 grade bolts dont stretch anything like as much as genuine ford/cosworth bolts and if I had to use them again (which I wont) I would probably be looking to do a 90degree final turn and then once all settled check for 110nm on all bolts.
#5
if you use ARP stud & nut kit then final torque is 120nm then re torque after engine has been @ full work temp and have cooled down to normal temp, which you take one bolt at a time, loosen half a turn, and tighten 120nm
#6
thanks for the replies. they're all still tight. after taking the cm cover off i think it was leaking from one of the rubber gaskets at the front running down the front of the head and then getting blown back to make it look like it was leaking from the head.
thanks again
also any front drive shafts for a 4x4 for sale?
thanks again
also any front drive shafts for a 4x4 for sale?
#7
A very common leak place at the front is where people don't put sealer under the front cam caps, and it needs it for sure.
10.9 are NOT stretch bolts, stretch bolts are a different material that maintain a certain degree,(albeit small) of elasticity like a spring.
I use ARP and just torque to 120 lbft, leave at least 2 hours then retorque to 120 lbft again, works for me.
tabetha
10.9 are NOT stretch bolts, stretch bolts are a different material that maintain a certain degree,(albeit small) of elasticity like a spring.
I use ARP and just torque to 120 lbft, leave at least 2 hours then retorque to 120 lbft again, works for me.
tabetha
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#8
can understand retorquing them to make sure their the same but if you loosten them half a turn like suggested wont that effect the crush on the headgasket?! as its already been compressed the first time round.
Just wondering really before i do mine, plus whats best to torque long studs up to 120lb ft too?!
Just wondering really before i do mine, plus whats best to torque long studs up to 120lb ft too?!
#9
A lot depends on what gasket you are using as well, if using group a I always use 120lbft, as it is a compressable gasket due to it's excellent fibrous nature this is why I let it rest before retorquing.
tabetha
tabetha
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