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General => The garage => Topic started by: Chris. on 19 September 2012, 18:12
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Has anyone ever builty a head themselves? Ill need to be doing the full thing including the guides.
Is it something someone whos handy with a spanner can do themselves with a valve spring compressor?
WHat potential areas can there be to go wrong? I understand you can seat the springs wrong, but is there anything else?
Valves will need lapping in of course.
Chris
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Maybe totally off topic, but on the DERVs unless you use only OEM washers for the injectors then the injectors will sit pissed as non OEM ones are different in some way.
I'm probably talking tosh and you defo know more than I do...Just a thought :lipsrsealed:
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20v is quite a basic head to rebuild tbh.
may need to ream the valve guides after youve pushed them in
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Ream the guides?
How best is it to push them in? Understand its best to put the guides in the freezer overnight to shrink them a bit.
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meany ways of pushing guides in. you really should use a small press. but sometines you can wind them in with a small bolt going down through the guide to a plate on the head face or even just tap them in if your carefull.
reaming them, reamers are used to accuratly open up holes to specific size and ensure the holes are round, drills can't be used as they just arn't accurate enough.
some valve guides don't need reaming after fitting some do chances are the valve stem will fit though the guide before fitting but after fitting it may not, youve not done anything wrong but as the head is squeezeing the guide and the hole though it becomes slightly undersized ( this is good as it means the guide is held in the head very securely ) a reamer is then used to open up the guide to the exact size required for the valve stem. t'll take feck all metal off can ether be done with a hand reamer or in a battery drill just rember to give the ream a littel oil and they run much slower than drills but with more pressure
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Is 'reaming' the same as 'honing'? Sorry, just want to clear up the jargon :lipsrsealed: :embarrassed: :whistle:
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From how I understand. When ths guide is pushed onto the head. It may squash the hole in the centre, so all the ream does is ensure the hole is exactly 7mm for VW applications
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Is 'reaming' the same as 'honing'? Sorry, just want to clear up the jargon :lipsrsealed: :embarrassed: :whistle:
they are diffrent
honeing is used on cylinder bores to take them out to final size and prepare the surface to required roughness.