should i fit valve lube kit to my 4.2 sc ,,80,000 miles or not some say do some say defo not

I belive its only the BMW engines that doesn't require flash lube

Yep, agree, you do need it for that engine...

Or get the valve seats changed..... Pete

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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

how much am i looking at to get them changed

if i do get the kit how long will the seats last as opposed to not fitting them .thanks

Depends on too many variables to hazard a guess, depends how you drive and how the gearbox treats the engine, it usually takes many 10's of thousands of miles to do significant damage, but could do it in a lot less, seen it done in less than 12,000 miles on some engines...

If it has been run without lube for any length of time, get the compression in the cylinders checked, if it is low then you need new valve seats (exhaust) and valves before fitting a valve lube. Obviously check for worn rings before diving in as it could have low compression and be nothing to do with LPG...

Replacement seats and valves will be expensive as there is a lot of labour and machining, I would guess well over £1,000.

The reason the later ones are worse is down to the bean counters again, using inferior materials and parts, the cheapest they can get away with.... Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

thankyou