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Discussion Starter #1
Dear Forum,

Can anyone instruct how to adjust the tappets on an M50 non-vanos engine?

I understand that having the tappets adjusted and set correctly will improve fuel efficiency.

New shims required at 100 000 miles? How do you fit them?

Advice and links please.
 

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The last engine i shimmed up was an old Jag straight six so I'm a bit out of touch with the newer engines but what i can tell you is if the process is still basically the same you will need a fairly good knowledge about mechanics.
For starters you will need a micrometer and know how to read one correctly as it's not as simple as remove old shims and fit new set as the clearance on each individual rocker will vary plus if you get your calculations wrong you won't know until the whole thing is re-built and checked the gaps so if it's wrong you have to start all over again.
As i said I'm out of touch with the procedure and it may well be a lot easier these days but i doubt it if I'm wrong another member will put me straight and in turn point you in the right direction:thumbsup
 

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Discussion Starter #4
M50 engines have hydraulic tappets, no adjustment is possible.
Does hydraulic mean that they adjust themselves? Is this what is called the lifter? The opening and closing of the valves relative to the cam shaft is hydraulically adjusted?

I stand corrected about having to replace the shims then. I could have sworn I read that somewhere.
 

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Does hydraulic mean that they adjust themselves? Is this what is called the lifter? The opening and closing of the valves relative to the cam shaft is hydraulically adjusted?

I stand corrected about having to replace the shims then. I could have sworn I read that somewhere.
The S38 engine for the e34 M5 has shims...

You may have read this http://www.bmwe34.net/E34main/Maintenance/Engine/valve_adjust.htm about the m20 / m30 engine


The M50 engine (520i / 525i/x) has non adjustable hydraulic tappets. They do get dirty though and may need to be cleaned see http://www.max-boost.co.uk/max-boos...an and recondition your Hydraulic Tappets.htm

My 158,000 mile 525iX has a tappety sound for about 5 seconds on start up, its usually less after an oil change

Some other posts about this below:

http://forum.bmw5.co.uk/topic/54871...197__hl__hydraulic__fromsearch__1#entry567197

http://forum.bmw5.co.uk/topic/55549...696__hl__hydraulic__fromsearch__1#entry574696
 
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