Cylinder Head

[NSL190]

Hi to All
I am new to this site and seek advise re the minimum allowable thickness for a 63 230sl M127 cylinder head to maintain at least the minimum inlet valve to piston clearance. I have recently completed a full restoration on my 48year owned 190sl and the cylinder head on the 190SL suffers from the same issue re clearance after machining. A cylinder head gasket shim is available for the 190 but I have not been able to find one for the 230SL engine so consequently I am worried that should I have to machine the 230SL head again it will be only good for a boat anchor. I can see that it has been machined at least once before and it now measures 83.36mm.Any advice is appreciated.
Ross Horton
Australia               

[Benz Dr.]

That's really been machined a lot when 84mm is the minimum. Turn your engine over to 5 degrees past TDC on the number one piston. Move the intake valve down until the valve touches the top of the piston and measure how far it moves past what the cam lobe has moved it. You need .9 mm clearance at this intersection point or the valve can hit the piston.

If it still clears, I would use .015 -.020 " of camshaft bearing shims to raise the cam higher because the valve seats likely also cut deeper. The odds of being able to be able to continue using this head are not high.

[WRe]

Hi,
see workshop manual: Minimum 84mm.
...WRe

[MikeSimon]

i am not sure what the experts' opinions are on this, but for motorcycles, we have used two headgaskets to raise the head if the thickness or height is borderline. It doesn't do much, but it may help.

[NSL190]

Thank you all for your much appreciated replies.
Based on those comments and the condition of my cylinder I will have to bite the bullet and purchase a new cylinder head from Niemoller in the new year. Expensive but these beautiful cars are worth it. Can anyone comment on the quality of the new cylinder heads from Niemoller. I did question them re the country of origin but they did not comment. I am a bit wary re the quality of some of the aftermarket parts that I purchased and had to discard while restoring my 19OSL. 
Cheers from Australia
Ross Horton           

[Benz Dr.]

You can also use a 250SL head if you can find one.

[Cees Klumper]

€4,300 yikes (without VAT - or shipping). I would definitely look for a used one.

[MikeSimon]

No VAT if shipped overseas. May have to pay customs duty, though.

[stickandrudderman]

New heads are available direct from MB which is likely where Niemoller will source it from. Here in the UK there is a shim available to regain the lost height and I have in the past, in consultation with an impoverished owner, fitted two headgaskets with good long-lasting result.