Pudock Posted June 30, 2010 Share Posted June 30, 2010 I know that its hard to judge from a photo, but does this look like a crack that I should worry about or is it just a score? The head is of to replace piston rings on the number 1 piston. This is number 2 piston. Thanks Quote Link to comment Share on other sites More sharing options...
Les Henson Posted June 30, 2010 Share Posted June 30, 2010 Looks like a crack to me, but then it's hard to judge from the pic (what would make a score like that inside the engine?). TD's are well-known for pistons cracking, and I've seen a fair few. Usually - a cracked piston will allow compression to pass through the crown and into the sump, where oil is then pushed out (usually) the breather pipe and into the air filter. Have you cleaned the piston crown prior to taking the picture? A crackerd piston crown is usually black - due to the reduced compression. Les. Quote Link to comment Share on other sites More sharing options...
western Posted June 30, 2010 Share Posted June 30, 2010 looks like a score mark, if you have a magnifying glass or similar have a good look at it, TD pistons do crack with age/heat stress on the engine, so changing all 4 might be a better move. Quote Link to comment Share on other sites More sharing options...
Pudock Posted June 30, 2010 Author Share Posted June 30, 2010 I did not clean it much before the photo, just a wipe with a rag. Pistons 3 and 4 had more burning on them than that but are fine. Piston 1 is fine but it was covered in oil. I'm hoping not to spend to much fixing it. The only reason I took it apart myself was I could not justfy the expence of getting the garage to open an old TD up to tell me that its all shot. So I'm trying to balance between repairing or replacing the engine. Thanks for the answers guys Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted June 30, 2010 Share Posted June 30, 2010 Time for an old Disco 200 Mo Quote Link to comment Share on other sites More sharing options...
Les Henson Posted June 30, 2010 Share Posted June 30, 2010 I have never yet replaced any piston on a TD engine - other than those that are cracked (usually 2). Piston kits (piston, rings, piston pin, circlips), are only about £20-£30 each, so no great expense really. A head gasket and maybe rocker gasket, inlet/exhaust manifold gaskets, some RTV sealant for the sump (or a series sump gasket if you prefer), will set you back about another £30, so a couple of hours overtime will cover the total cost of repairs Les. Quote Link to comment Share on other sites More sharing options...
trickydicky Posted July 1, 2010 Share Posted July 1, 2010 hi mine were alot more cracked than that and they didnt cause me any probs . when i did change them i found that it drank the oil for the first 500 miles or so but now its fine .the hardest part was lying on my back with oil dribling on my face but at least i sorted the leek on my sump . Quote Link to comment Share on other sites More sharing options...
Pudock Posted July 1, 2010 Author Share Posted July 1, 2010 On a slightly different note, the rings on my pistons are on in a different order from what the manual says. My rings are oil control at the bottom then chamfered ring and then square section at the top while the manual says the chamfered ring should be at the top. Does the order really matter as the pistons have never been out in the 10 years I've had the car? Quote Link to comment Share on other sites More sharing options...
Les Henson Posted July 1, 2010 Share Posted July 1, 2010 The chamfered ring should be at the top so that the step that eventually forms at the top of the bore doesn't snap the ring. Should be chamfered, straight edge, oil control. Les. Quote Link to comment Share on other sites More sharing options...
Pudock Posted July 1, 2010 Author Share Posted July 1, 2010 The chamfered ring should be at the top so that the step that eventually forms at the top of the bore doesn't snap the ring. Should be chamfered, straight edge, oil control. Les. Thanks Les, I'll put them in the way you and the book say rather than the way the old ones came out. Quote Link to comment Share on other sites More sharing options...
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