Usually I find my answers in the archives but I find no reference to my present issue, so I will bother you folks if you don't mind. Let me start by saying it has been around 20 years since I have attempted a job like this. I'm finishing up a refresh/repair of my 2001 Merc 200 EFI. The heads are unlike any I have dealt with in the past. They are a block of aluminum of uniform thickness (approx 1-1/2") and use o-ring seals rather than head gaskets. My problem is with the head bolt that the detonation sensor screws into, top right head bolt on the port head. The bolt is no longer available. The head bolts on this engine are 3" long. The late 90's heads used a similar mounting arrangement but the heads were diferent and the head bolts are approx 2-1/4" long and are still available but are too short. My intent is to replace the 3" head bolt with a grade 8 stud and grade 8 connecting nut which will have enough extra thread to mount the sensor. Will this work or is there something I am missing? When it was available the head bolt sold for over $60. Even for Mercury that sounds high for just a 3" bolt with an extra thick head that was drilled and threaded. Help please!
