How to replace piston on cylinder six?

Hi,

That requires the engine to be removed, taken apart, and basically rebuilt. Why do you feel a new piston is needed? If that is what is needed, there is likely other damage, so let me know. Note: This is a big undertaking and shouldn't be done if you are not experienced.

Let me know.

Joe

As Joe alluded to, it is very likely that if you have a damaged piston, it's very likely you have more damage than that. If you dropped something in the engine and it got into the cylinder and damaged it, then there is likely damage to the valves, cylinder head and possibly the engine block as well. My first step would be to use a bore scope and look inside that cylinder and inspect it for damage first. Look at the piston, bore and cylinder head surfaces for damage. If there is any, I would consider replacing the engine over the alternative of rebuilding it, unless there is no choice. Please let us know what you find and why you feel it is bad. Thank you.

Only two ways, use a camera to look inside the cylinder and inspect things, or remove the head and inspect it. The second option is the better one but the question is still, what makes you think the piston is damaged? That is also something that you would need to inspect in the same manner.

How are you able to shake the piston? You have the engine out and apart or? That sounds like it could be more than just a bad piston. Can you take a video of it and post it here?

Okay, that's normal. The pistons start a bit loose in the bores and as soon as the engine starts they heat up and expand. If there were no room they would expand and lock in the bore. If the others don't move a bit in the bore the rings are likely carboned up and stuck in the grooves. As you have it that far apart I'd suggest doing a refresh on it. Pull the engine out the rest of the way. Pull the oil pan and remove the crankshaft and inspect all those bearings (or just replace them. While it's apart remove the old piston rings, install new rings and use a simple hone it each bore just to break the finish on the cylinder walls. Clean up the residue and put it back together. Reseal the cylinder heads and lap in the valves and you would have a better engine. Because of the lack of any damage the cylinder head shouldn't be a problem. Now if you wanted to you could actually go the full rebuild route and not just a refresh. That would involve removing the engine, stripping the block and sending it and the crankshaft to a machine shop and having the cylinders bored to the first oversize that has pistons available, line honing the crankshaft saddles and having the connecting rods resized and all new pistons, rings and bearings fitted. Now do the heads and you would have a "new" engine.

Use a scraper to clean the surface real well, then get a straight edge and some feeler gauges to verify that the flock and head are actually flat. When a head gasket fails it's commonly because the surfaces are not flat, and the gasket isn't clamped evenly. There are a couple engine build series on this sites YouTube channel that show some of the measurements. That works for most engines. More videos of the various items you do at https://www.youtube.com/@JAMSIONLINE as well.

I wouldn't try to surface a block with sandpaper. Far to easy to cause problems.

That works for old iron heads if you are not really worried about introducing other errors. Aluminum is different because it is very easy to ruin a head that way.

Aluminum is fussy about the surface finish as well so it's really better to check it for flat first using a straightedge and feeler gauges and if it needs work have a machine shop true it up. It really depends on how long you plan to keep the car. You could have the machine work done and go through the engine and it would last another 100 thousand or more miles, but is the rest of the car in good enough shape to justify the cost? If yes, then do a full rebuild and enjoy it. If the rest of the car is questionable then maybe use that technique with some 400 grit paper just to see if the head is bad or use the straight edge, and if it's not really bad just bolt it back together with new gaskets and bolts and call it close enough and drive it. Those become a judgement call that you would need to make based on the actual conditions you have.