Gentleman.............
You guys are beginning to go off topic here *sigh*......please start a new thread for this purpose if you insist on carrying on this discussion, thank you..............
To answer this thread:
A top overhaul is done when the following situation arises:
1) Excessive consumption of engine oil due to worn valve guides.
2) Noisy hydraulic lifters need to be replaced.
3) Excesive carbon build-up in the compression chamber and/or on the valves and the valve seats.
4) Camshaft is worn out.
.........these are some common scenarios which would require a top overhaul. These are the ones off the top of my head, there are more believe me.
BTW, a compression test is usually performed to determine the condition of your piston rings and very rarely indicates that you need a top overhaul!
A top-overhaul :
1) Removing the cyclinder head
2) Replacing all the valve guides (if necessary)
3) Replacing the neccessary worn vavles.
4) MUST replace all valve seals.
5) Must re-grind and re-seat valves (to ensure proper compression is achieved)
6) Replacement of the camshaft if neccessary.
7) Replacement of cam bearings and seals.
8) Of course everything needs to be thoroughly cleaned, including the combustion chambers and oil and water passages.
9) New head gasket set upon re-installation.
10) All bolts MUST be replaced in BMW engines as they are consumables and can never be reused!!! You have been warned!
This is just a rough guideline as I'm trying to keep it on layman's terms. If I have missed out anything, please feel free to add on to this reply, which is far from perfect.
Hope this helps.
coz I dunno what I'll be doing for a whole day at senawang.....eh got spa there arrr?.....
