This is a copy of a post in my rebuild thread https://forum.ih8mud.com/40-55-series-tech/224775-south-african-bj40-rebuild-into-fj40.html Those of you that have been following this thread will know that I picked up an engine knock from continually driving the truck to overheating in the Kalahari Desert in December. Before I went to Europe I pulled the motor and cogbox out in preparation for pull down and rebuild. Well. Yesterday I pulled the motor apart and sh1t did I get a shock.:whoops: I lighted sanded the top of the cylinders with abrasive tape to prevent the possibilty of the rings snagging. Wasted my time The 1st piston I removed was no 6, the second compression ring was broken into about 10 pieces. The 2nd piston I removed was no 1, the second compression ring was broken into about 15 pieces The 3rd piston I removed was no 5, the second compression ring was broken into about 8 pieces The 4th piston I removed was no 2, the second compression ring was broken into about 6 pieces The 5th piston I removed was no 4, the first (top) compression ring was broken into 3 pieces, and the second compression ring was broken into about 15 pieces, and the piston had 4 score marks down its side (but no damage to cylinder) The 6th and last piston I removed was no 3, the second compression ring was broken into about 4 pieces My assumption is as follows; the fact that I was constantly driving the truck in 45deg ambient temps in the desert, to the point of overheating, then waiting for it to cool down then continuing on further until it overheated again, and this continued for over 500km, has accounted for the broken rings and no 4 was the first piston to break its rings (but:- assumption is the mother of all fekkups) BTW - when I rebuilt the motor - the pistons were Yota original, but the rings were from Terrain Tamer - Aussie. I would be very interested to hear any and all other theories on the causes of ring breakage especially when it is only the 2nd compression ring.