Rebuilding, scored cylinders
#1
Rebuilding, scored cylinders
Hello everyone,
I got a 1998 b5 a4 quattro with the 2.8 30v AHA engine and the 5 speed DBJ transmission and I wanted to rebuild it because I'm trying to learn as much as possible. I pulled the engine/trans and got the engine stripped down to the block. At that point my heart sank. 3 of the cylinders have scoring that I can catch a nail on. Is there anything I can do at this point, or is it a complete loss? The machine shops I've talked to all say I got a bad break and there's not really anything I can do, is that true? Pictures to follow as soon as I get home from work. I would appreciate any advice or insight anyone may have as to what I should do next. I'm feeling pretty bummed about it but I'm not ready to give up just yet.
I got a 1998 b5 a4 quattro with the 2.8 30v AHA engine and the 5 speed DBJ transmission and I wanted to rebuild it because I'm trying to learn as much as possible. I pulled the engine/trans and got the engine stripped down to the block. At that point my heart sank. 3 of the cylinders have scoring that I can catch a nail on. Is there anything I can do at this point, or is it a complete loss? The machine shops I've talked to all say I got a bad break and there's not really anything I can do, is that true? Pictures to follow as soon as I get home from work. I would appreciate any advice or insight anyone may have as to what I should do next. I'm feeling pretty bummed about it but I'm not ready to give up just yet.
#3
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It's not untypical to see scoring like this, generally it's caused by little pieces of carbon that's trapped between the ring and cylinder. If you are well within bore size I'd hone it and go again.
#4
AudiWorld Member
I agree. I'm no machinist or professional auto mechanic but I see only light scoring. Where's the scoring that will 'catch a nail'?
If you're talking about the ridge at the top of each cylinder that's ordinary wear on a high mileage engine. That ridge is the metal above the top compression ring that has not worn with piston travel. There are tools to remove the ridge.
The basic question you'll have to answer is what is your goal? Are you seeking to rebuild an engine for practice and learning? Do you want to rebuild the engine yourself and reinstall it in an old high mileage car for a transportation car? Do you want the cheapest rebuild possible that will run and provide transportation but may use a little oil and not be as strong as it was when new?
My amateur opinion is that engine can probably be rebuilt by removing the ridge at the top of each cylinder, honing the cylinders carefully (don't remove too much metal), and put it back together with standard rings and bearings. It won't be a high performance engine but it will run unless there is something I can't see like scored crankshaft journals.
If you're talking about the ridge at the top of each cylinder that's ordinary wear on a high mileage engine. That ridge is the metal above the top compression ring that has not worn with piston travel. There are tools to remove the ridge.
The basic question you'll have to answer is what is your goal? Are you seeking to rebuild an engine for practice and learning? Do you want to rebuild the engine yourself and reinstall it in an old high mileage car for a transportation car? Do you want the cheapest rebuild possible that will run and provide transportation but may use a little oil and not be as strong as it was when new?
My amateur opinion is that engine can probably be rebuilt by removing the ridge at the top of each cylinder, honing the cylinders carefully (don't remove too much metal), and put it back together with standard rings and bearings. It won't be a high performance engine but it will run unless there is something I can't see like scored crankshaft journals.
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