At 67k miles my 659cc engine lost all compression in cylinder number 3. The exhaust valve went out. Luckily it didn't seem to damage the piston or cylinder walls (I don't see any marks) The turbo seems to be fine too? There's no play in the shaft or visible damage. I may have gotten lucky. These things that sit on top of the valves. Their job is to have correct clearance of the cams and push the valves down (spring brings them back up) These can wear down causing improper clearance resulting in incorrect valve closing/opening which can result in burnt valves (combustion leaks past valves heating up the backside of them wearing out the material quickly) These are unique to each engine. Notice the number on the side? This is so you can identify which size they are. Each valve will have a different size, some may be 22 others my be 15, may also have multiple 23s etc... I suspect these could've caused my problem. I bought new exhaust valves, here's a picture of them in original packaging so you can see the part number 13715-87210- I got them from an ex Daihatsu dealer and bad news for anyone needing new valves... There are only 3 left in the UK and I bought all of them. Any more can be ordered from Japan. I am going to replace all 8 exhaust valves because they look a little worn (small craters and marks on the backside + buildup of idk what it is, like burnt oil or something caked all over them) My engine was also burning some oil, I suspect valve stem seals could've caused it so I'm replacing those too. I am also replacing the PCV valve because I saw some oil in the intake. I am sure it's not oil from the turbo because the turbo is bone dry. If you have any wisdom to share please do so, I'm still waiting for the remaining valves to arrive from Japan so it will be a while before I resume work.
Yes, most are in spec, some are just barely within spec and a few were out of spec. On the intake side I was able to swap some lifters around to get them within spec, however a couple are right on the edge, so I will order different sized lifters for those once the exhaust valves are installed and measured. For anyone wondering, it should be 0.20mm (+0.055 -0.035) on the intake and 0.30mm (+0.055 -0.035) on the exhaust side.
Lapped some of the valves, here's a side by side before and after picture in cylinder number 1. A few tiny pits left in the photo which has since come off after 1 more go with the fine grade paste.
