02GF74
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 posted on 2/12/09 at 07:39 PM |
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x/flow c/head - what do I do now peeps?
took the head off. head gasket looks complete but a quick visual showed both the middle brass exhaust vavle guides had shifted 
removed asll valves from middle cylinders and although the inlet guides are fine, both exhaust guides move up and down; one appears seized on the
valve. 
my theory that the head got so hot, the cast iron expanded to allow the brass guide to move and this wore the guide down so that it is now loose.
furthermore the moving guides had uncovered a water channel (both pistons had water on them).
I cannot see nor feel any cracks in the head so it may be ok.
So, what do I do now peeps??
Do I attempt to removethe guides - one is almost out - or send it to the company that did the head?
For sure it will need new guides. ... but it could have been worse (assuming my theory ^^^ is correct).
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prawnabie
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| posted on 2/12/09 at 07:43 PM |
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Like I said in your other post I have a mexico head with opened out inlet ports if you want it, you just need to arrange collection!
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02GF74
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| posted on 2/12/09 at 07:47 PM |
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quote:
Originally posted by prawnabie
Like I said in your other post I have a mexico head with opened out inlet ports if you want it, you just need to arrange collection!
ta for offer - I will be up in B'ham so in your area over Christmas.... but my head is well ported, has unleaded exhaust inserts plus oversized
inlet and exhaust valves and cost a fair bit so I'd rather get it fixed if possible.
If I am correct, then it just needs 2 guides plus reface of valve seats - the last bit not too happy about since the valve will not longer sit at same
height but ...
[Edited on 2/12/09 by 02GF74]
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steve m
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| posted on 2/12/09 at 08:26 PM |
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I share you xflow turmoils, as i did have a very nice home brewed 1691 stage 3 that went like stink, and then it stopped,
The xxx branded head disintegrated itself, 2 unleaded seats fell out and broke up so the valves had nothing to seat on !!
so off it went to "xxx" to be recified and they dismissed the whole saga with a disclaimer,
3 years down the line and no car on the road subject to an engineers report on that engine, i have given up
I now have a 1660 stage 2, that will be rev limited and run rich
as im 3 yrs older and slower, i might not notice the drop in performance !!!
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MikeR
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| posted on 2/12/09 at 10:08 PM |
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If its not taken .... how opened out is the head?
(not sure why i'm asking as i have a spare head - but its not modified).
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mark chandler
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| posted on 2/12/09 at 11:08 PM |
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Send it back in disgust in the first instance, they may have opened the valve guides to far before pushing in the bronze guides, the second your
fingers go in they will turn you away.
Got to be worth a punt, but refrain from paying them for any more work.
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MikeRJ
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| posted on 2/12/09 at 11:51 PM |
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Is it normal to break into the water jacket when maching an xflow head for valve guides?
Make sure the valves and guides are compatible materials, some combintions don't work. My brother found this when the valves picked up and
partialy seized within bronze guides in his mini, made a real mess of the valves and guides.
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02GF74
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| posted on 3/12/09 at 07:14 AM |
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quote:
Originally posted by MikeRJ
Is it normal to break into the water jacket when maching an xflow head for valve guides?
no - my mistake - was able to knock out both guides easily enough.... so I'm back to BT's 'not enough torque' theory.
I do not think it is machinng fault - the head got very hot on the exhaust side - some of the cork rocker box gasket had burnt away , not to
mention all the paint.
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