mitch2b
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| posted on 12/10/06 at 01:52 PM |
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vauxhall porous fix?
Hi All
I seem to remeber a while back a company in Nwest who did the porous fix on VX's very cheaply, anyone know who they were, Warrington/Wigan areas
i seem to remeber,
Anyone help?
Mitch
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jimmyjoebob
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| posted on 12/10/06 at 03:45 PM |
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A firm in Coventry used to fix porous cylinder heads by bead blasting. I think they were called Impact finishers.
If at first you don't succeed, hide all evidence you ever tried!
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dilley
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| posted on 12/10/06 at 04:01 PM |
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if its porous it will need a bypass tube fitted on one of the waterways, this is a common problem on the gm heads, look out for a cos-cast head as
these dont suffer.
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dilley
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| posted on 12/10/06 at 04:04 PM |
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Im actually doing one on a cavalier turbo for a friend, it results in oil being mixed with water, this can be visible in the header tank and is quite
often wrongly diagnosed with a head gasket, also check all rubber pipe work as somtimes these can become perished, also get your rad cleaned out
properly and maybe the heater matrix.
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david walker
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| posted on 12/10/06 at 04:48 PM |
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There is NO WAY you can fix a porous XE head by bead blasting!
I haven't seen anyone doing them cheaply either, it isn't a quick repair. Going rate was about £250, cheaper to buy another head.
Coscast heads can be guaranteed to be OK and it is for that reason the Coscast is preferred - they don't make more power. Most later GM ones,
such as from '94 Calibras and Cavaliers are usually the worst culprits with a large proportion by now porous.
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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mitch2b
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| posted on 12/10/06 at 05:50 PM |
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no its porous, im sure it was on here, and it was the machined tube method, but was a lot cheaper than that Dave.
Mitch
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the_fbi
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| posted on 12/10/06 at 08:51 PM |
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Its nothing to do with porousity either, its a crack in the head between oil and waterways.
Coscasts aren't failproof either, there are cases of them failing too.
Generally it happens due to a head gasket being changed and incorrect torqueing with the gasket being used.
Chris in Warrington is who you need 
£40
http://www.migweb.co.uk/forums/vauxhall/items-sale/260018-porous-heads-fixed-40-a.html?
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david walker
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| posted on 12/10/06 at 09:37 PM |
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I've looked at your link and I take my hat off, £40 is cheap!
I agree that £250 is to much but up until about 3 years ago when s/hand replacements were not available that was the going rate and offered by many
"specialists" around the country. Where I used to work we tried having about 3 done, all failed.
I've fixed my own in the past by plugging the cross drilling where the problem is and routing the oil feed externally through braided hose -
which is another std fix but really only suitable for engines where the owner knows what's happening, ie not shopping cars!
I have never seen, or heard of a Coscast head leaking like this, never.
I also dispute your claim that it is always crack, some are but most are porosity within the casting, where the casting thickness is little between
the oilway and water jacket.
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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the_fbi
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| posted on 12/10/06 at 09:44 PM |
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quote:
Originally posted by david walker
I also dispute your claim that it is always crack, some are but most are porosity within the casting, where the casting thickness is little between
the oilway and water jacket.
The casting thickness is little which causes a weakness, hence the crack.
Plenty of threads on it, complete with disected head pictures on migweb. All have shown a physical crack rather than porousity.
Threads worth reading on the subject...
http://www.migweb.co.uk/forums/vauxhall/mechanical-electrical/139841-20xe-porous-head-definitive-answer.html
http://www.migweb.co.uk/forums/vauxhall/mechanical-electrical/136586-long-awaited-sectioned-head-photos.html
[Edited on 12/10/06 by the_fbi]
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ecsjwhi2
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| posted on 12/10/06 at 11:37 PM |
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It is both cracking which occurs and also porosity of the metal......
http://www.topbuzz.co.uk/info/porous_heads/porous_heads.htm
Try these fellas
Engineering firms to fix the porous heads:
Headway (Costs £225 cash)
Unit 16 Garden City Industrial Est
Sealand Avenue
Deeside
Flintshire
tel 01244 821921
Cheers
JohnW
[Edited on 12/10/06 by ecsjwhi2]
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mitch2b
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| posted on 13/10/06 at 06:16 PM |
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cheers, thats the guy, now to get it off to him
Thanks again
Mitch
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