Pulling M103 head - any hints/pitfalls/etc.. ?
08-16-2007, 01:16 PM
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'90 300E Blk/Tan
Pulling M103 head - any hints/pitfalls/etc.. ?
I will be pulling the head off my '90 300E's M103 engine this weekend for a valve job. Are there any tips, pitfalls, "be careful's", etc. to know about? For example I have seen these for the M104, but do they apply to the M103 as well? (especially #5 and #7):
1) a good time to replace the chain/tensioner also
2) always replace head bolts
3) replace the egr pipe
4) Watch the dowel pins for the intake. They often fall out during removal
5) "..no matter what anyone says, be sure and use a head gasket from MB. They have added Stainless inserts into the gasket at the front areas that leak. AND that special gasket is make only by ELRING!!"
6) If your lower timing cover is leaking now is the time to reseal. Make sure you clean the timing cover and block very well and use the gray permatex not the cheap red sealant .
7) "I have been called to a couple of general repair shops to diagnose broken cams after the work is completed. It turns out that many people are not aware of the fact the chain tensioner has to be run all the way through and re introduced through the closing plug. The chain just sings with the tensioner is ratcheted all the way forward."
Thanks guys,
Andy
1) a good time to replace the chain/tensioner also
2) always replace head bolts
3) replace the egr pipe
4) Watch the dowel pins for the intake. They often fall out during removal
5) "..no matter what anyone says, be sure and use a head gasket from MB. They have added Stainless inserts into the gasket at the front areas that leak. AND that special gasket is make only by ELRING!!"
6) If your lower timing cover is leaking now is the time to reseal. Make sure you clean the timing cover and block very well and use the gray permatex not the cheap red sealant .
7) "I have been called to a couple of general repair shops to diagnose broken cams after the work is completed. It turns out that many people are not aware of the fact the chain tensioner has to be run all the way through and re introduced through the closing plug. The chain just sings with the tensioner is ratcheted all the way forward."
Thanks guys,
Andy
10-31-2007, 02:13 PM
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OK, here's what I learned in the process:
1) As someone pointed out to me, many people are not aware of the fact the chain tensioner has to be run all the way through and re introduced through the back side, essentially resetting it to min tension extension. Replace the chain tensioner while your doing this, you have 95% of the work you need to do for that done anyway, and it is inexpensive.
2) Watch the dowel pins for the intake. They often fall out during removal - True
3) Make sure you use some silicone to help the timing cover gasket seal. I tried to clean the surfaces thouroughly and use the gasket alone...it leaked anyway. Siliconed the ends of the gasket a bit when I removed the timing cover the second time - no leaks (and I use Mobil 1).
4) When you pull the head, check which cyllinders have been blowing by back into the intake. Replace those injector nozzles. My car still idled a bit rough even after the valve job - until I replaced those injectors. Now it's smooth as silk.
1) As someone pointed out to me, many people are not aware of the fact the chain tensioner has to be run all the way through and re introduced through the back side, essentially resetting it to min tension extension. Replace the chain tensioner while your doing this, you have 95% of the work you need to do for that done anyway, and it is inexpensive.
2) Watch the dowel pins for the intake. They often fall out during removal - True
3) Make sure you use some silicone to help the timing cover gasket seal. I tried to clean the surfaces thouroughly and use the gasket alone...it leaked anyway. Siliconed the ends of the gasket a bit when I removed the timing cover the second time - no leaks (and I use Mobil 1).
4) When you pull the head, check which cyllinders have been blowing by back into the intake. Replace those injector nozzles. My car still idled a bit rough even after the valve job - until I replaced those injectors. Now it's smooth as silk.
