Hey everyone I have another d353 in the w/shop that has had the counterbore machined, there are 2 types of counterbore inserts for the d353 blocks, one is about 1/4 of an inch wide, and the other is about 1/2 an inch wide, the 1/2 inch wide insert requires the block to be machined out all the way into some of the water galleries and head stud holes, this engine has coolant coming up some of the head stud holes, which worries me a bit but I am thinking coolant is coming through the water galleries and around between the machined block surface and the insert and up the head studs, I hope that makes sense! it does in my head but its hard to explain! has anyone every had trouble with this sort of thing? its the first time I have come across such a problem
I did those inserts from the get go and what I did was to tap out the stud holes with a tapered tap, very gently cleaning and not cutting anything. The taper lock studs require the taper tap profile to lock in. Then after that was done I filled the stud threads full of RTV silicone and when installing them and seating them. After seating them silicone would just come to the block top surface. Later Bob