02GF74
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| posted on 26/11/05 at 08:47 AM |
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tell me about the porous head on vauxhall 16 V engines
Can someone tell me more about the porous head problem on Vauxhall 2.0 l 16 valve engines, 20 XE?
From what I have read, cosscast heads do not suffer this - how can you tell if head is cosscast (cosscast - something to do with Cosworth)?
Is there any way to fix a porous head - i.e. how and how much?
Any other info. appreciated.
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Ben_Copeland
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| posted on 26/11/05 at 09:17 AM |
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The Coscast head will have coscast stamped on the underside of the head between exhaust ports 2 and 3 i think. There is also other things, which i
cant 100% remember but a qucik search on here will reveal them !
It can be fixed, and can be DIY, i have the info somewhere on doing this. But it's generally best to get someone to do it for you if your not
sure.
I've just picked up a full engine with GM head and shortened sump for £90 and intend on repairing the GM cos it['s porous. Though no rush
cos i have 3 full engines at the moment 
Ben
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ned
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| posted on 26/11/05 at 09:25 AM |
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its mostly the later gm heads that suffer from this, due to a slightly softer alloy used for the casting and a weak point between an oilway and
waterway where a crack can occur on higher milage engines.
It can allegedly happen to any head, but i've personally only seen it once on a late dizzyless head (has two lugs on the back of the head for
the wasted coil pack)
for identifying a oscast head, see my website: http://www.locostbuilders.co.uk/users/ned/engine/16v/engine_identification.htm
Ned.
[Edited on 26/11/05 by ned]
beware, I've got yellow skin
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the_fbi
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| posted on 26/11/05 at 02:13 PM |
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quote:
Originally posted by ned
its mostly the later gm heads that suffer from this, due to a slightly softer alloy used for the casting and a weak point between an oilway and
waterway where a crack can occur on higher milage engines.
Not just high milers, the number of people who miss-torque the heads down again due to not knowing if its a dry thread torque, getting ft/lb's
and nm mixed up etc.
A couple of great threads/pics are at
http://www.migweb.co.uk/forums/showthread.php?t=139841
http://www.migweb.co.uk/forums/showthread.php?t=136586
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