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+--- Thread: OM606 pre-chamber question (/showthread.php?tid=4560)
OM606 pre-chamber question - AlanMcR - 05-06-2013
I've had to do a valve job on my OM606 (long story). There was enough pitting of the face of the head that it seemed prudent to resurface it. The pre-chambers stick out of the head, so they need to come out beforehand.
The EPC shows a seal ring between the pre-chamber and the head. I didn't find one of those when pulling it apart. Also, the EPC lists three different versions of the seal ring, all "repair size", with no normal size ring. Is this seal normally needed, or is it only needed if one has had to repair the hole that the pre-chamber seals up against? Inquiring minds want to know.
RE: OM606 pre-chamber question - hansendk - 05-07-2013
Hi
its because the prechampers have a tolerance on the height from the cylinder head surface, so after resurface
put all the prechampers back in messure the height down to the sureface if its out of spec buy the size needed to get it inside the spec.
thats why they all stand as repair size, it has nothing to do with sealing only height
i cant remember the spec for the 604-605-606 but for the 601-602-603 its 7.6 mm - 8.1mm (if my brain is working correct)
Hansen
RE: OM606 pre-chamber question - AlanMcR - 05-07-2013
Well, that is what I thought too, however the facts don't seem to add up. There is only one repair size for the head gasket +0.2mm. Yet there are three sealing ring sizes 0.3, 0.6 and 1.0 mm, all thicker than the amount one is allowed to cut off the head.
Besides, since the head gasket has to be thickened by the same amount that the head is shaved, the position of the pre-chamber in the cylinder volume doesn't change.
So, still a bit confused. I guess it is going back in the way it came out.