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Christ · 05-02-2010, 12:21 PM

Unless you don't plan on pulling the engine, do the rings and a light hone anyway. If you're just going to pull the head, and don't want to touch the bottom end, then yes, it's either a burnt/cracked/bent valve, or it could also be a hole in a piston.

Most likely is the valves, unless you have a severely broken piston ring with a chunk missing, or another very obvious problem.

While you have the engine apart, it's probably also a good idea to diagnose and repair the almost 10% change in compression you have across the other two cylinders. More than likely, you have a valve seat issue on the 2nd cylinder, or gunk/carbon buildup that's preventing the valve from seating properly.

While you have the head apart, clean it thoroughly, and check/replace the valve stem seals, as well as the valve guides, if they're worn at all.

These are all things you won't want to have to do later, once you've already put it back together.

05-02-2010, 12:21 PM	#4 (permalink)
Christ Moderate your Moderation. Join Date: Nov 2008 Location: Troy, Pa. Posts: 8,919 Pasta - '96 Volkswagen Passat TDi 90 day: 45.22 mpg (US) Thanks: 1,369 Thanked 430 Times in 353 Posts	Unless you don't plan on pulling the engine, do the rings and a light hone anyway. If you're just going to pull the head, and don't want to touch the bottom end, then yes, it's either a burnt/cracked/bent valve, or it could also be a hole in a piston. Most likely is the valves, unless you have a severely broken piston ring with a chunk missing, or another very obvious problem. While you have the engine apart, it's probably also a good idea to diagnose and repair the almost 10% change in compression you have across the other two cylinders. More than likely, you have a valve seat issue on the 2nd cylinder, or gunk/carbon buildup that's preventing the valve from seating properly. While you have the head apart, clean it thoroughly, and check/replace the valve stem seals, as well as the valve guides, if they're worn at all. These are all things you won't want to have to do later, once you've already put it back together. __________________ "¿ʞɐǝɹɟ ɐ ǝɹ,noʎ uǝɥʍ 'ʇı ʇ,usı 'ʎlǝuol s,ʇı"