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Aug 04, 2015 10:59 am
Aug 04, 2015 10:59 am
Subject: Tappet clearances - why the variation?
I'm sure there's a simple answer to this one but I don't know it! All available guidance for the 2 Litre states that clearances should be 4 thou for the normal camshaft but 8 thou for a high lift one. Seems to me that, as the valves are the same (in length and expansion coefficient) and they are operating in the same thermal regime, there is no need for this change, given its unfortunate effects of reducing the open period and making an already clattery engine yet noisier.
Wise words please!
H54 John
I'm sure there's a simple answer to this one but I don't know it! All available guidance for the 2 Litre states that clearances should be 4 thou for the normal camshaft but 8 thou for a high lift one. Seems to me that, as the valves are the same (in length and expansion coefficient) and they are operating in the same thermal regime, there is no need for this change, given its unfortunate effects of reducing the open period and making an already clattery engine yet noisier.
Wise words please!
H54 John