[Synchro909]

I know this is an old thread but I take back anything favourable I said in it earlier. I have just set about relacing the inserts throughout my engine. The big ends were good but the mains are a mess. The lower insert on both the front and middle main bearings had a piece of babbit missing from the slot for the oil to enter to the edge (about 3/8"). This is not the first time this has happened to me but the big disaster was the rear main. The babbit was wiped all around the bearing due to lack of oil. These inserts are incredibly poorly designed. There is waaaay too far for the oil to travel to get to the whole length of the bearing as George Miller said early on. I intend cutting a spiral groove in the top insert and maybe the bottom too to get oil to the back of the bearing. Comments on that would be appreciated.
Why on earth did the makers not do what has been done for many decades with babbit bearings and cut an oil groove in them??? Sheer incompetence, in my book.
This thread is old enough now that maybe someone has made this modification and done a lot of miles on it. How did it go?
In an effort to make sure the bearing is able to get enough oil, I tried blowing air from the lower end with one side of the gap where the insert would have been blocked with the old insert and looking for something at the top. I didn't find much at all. Is anybody able to describe to me where the top end of the oil hole to the rear main bearing is located - perhaps in relation to the cam follower bosses. I can't get to my spare bloch at the moment.