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12G940 HEAD


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#1 Chewy

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Posted 25 May 2007 - 07:47 PM

Hey all


I am having a problem with my head on my 1275 MG Metro engine
12 and 4 cyclinders firing ok the plug is nice and brown but number 3 is oiled up and smokes a bit
the engine was rebuit. the head had new seats but no new valve guides the rings are all new
wiuld it be the valve guides that are worn are would it be the stem oil seals

I need help ASAP Many thanks

Chewy

#2 miniboo

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Posted 25 May 2007 - 08:04 PM

could it be a piston problem?

#3 Chewy

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Posted 25 May 2007 - 08:09 PM

Thanks


Waht do you mean by a piston problem

#4 miniboo

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Posted 25 May 2007 - 10:59 PM

as in a problem with the bore or a ring maybe?

#5 Jimmyarm

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Posted 26 May 2007 - 10:07 AM

Do a compression test which should show if there is a piston/ring problem.

More likely if it has been rebuilt is that someone forgot to put the valve stem oil seal on or used the old ones :blink:

Edited by Jimmyarm, 26 May 2007 - 10:07 AM.


#6 Chewy

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Posted 26 May 2007 - 02:36 PM

Many thanks to all of you

i am goin to take the head of 2morrow and i am going to strip it down and regrind all the valves in the seats and put new
stem oil seals on

many thanks

Chewy

#7 miniboo

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Posted 26 May 2007 - 04:27 PM

do a compression test before you take the head off though

#8 Dan

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Posted 26 May 2007 - 05:10 PM

Don't bother trying to grind it if it's unleaded. The unleaded seats are far too hard to grind with paste, they pretty much have to be machine cut. Valve stem seals don't do all that much really, if it was that bad a problem and it was head related I would think it was more to do with a worn guide but in this case I'm going to suggest the head gasket. It's far more likely.

#9 Chewy

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Posted 26 May 2007 - 08:03 PM

Thanks


To you all that have helped with sugestions i am goin to replce all the valve guides and the seals an re lap the valves in and replce the head gasket

I will report back when i have finished all th work


Many thanks to all of you


Chewy

#10 Chewy

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Posted 28 May 2007 - 06:30 PM

Hey

I have took the head of and bad news there is bore wear i put new valve guides and seals on still smokes the same as before so
when this engine gives up i will bore it it + 20 to 1293 would this be a good option

Thanks Chewy

#11 biggav

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Posted 28 May 2007 - 07:04 PM

you could have the one cylinder bored and lined but to be honest you'd be better giving yourself a bit more displacement at the same time... just keep an eye on the budget co these things always seem to run away with me and i end up with lots of lightene, performance and shiney bits and no money




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