Piston movement

[pwagon717]

When I had the head off, #1 and #6 piston had some movement in the cylinder. Meaning I had my finger on the top of the piston could wobble it a little from side to side. It kind of shock me. I am getting the blow- by and all the spark plugs are fouling out. Is it the head that is causing the problems, because I am still loosing some coolant.


Also one headbolt is stripping in the same hole, no other one are stripping, it has happened twice. What is reason for that?

[Ryann]

Some engines are known for developing this. Volvo b230's can have so much piston slap that it'll sound like rod knock at idle, but is totally harmless.

Compression test time.

[matias88e30]

i noticed same problem when i pulled my engine apart... doesnt knock, runs perfect

[jlevie]

Cylinders 1 & 6 run hotter than the rest and are usually the first to show wear. The motion of those pistons says that either the pistons or the bores are worn. A few minutes of work with a bore gauge and micrometer will tell which it is.

If one head bolt insists on stripping, the threads in the block are bad. That can be fixed with a thread insert.

[pwagon717]

Cylinders 1 & run hotter than the rest and are usually the first to show wear. The motion of those pistons says that either the pistons or the bores are worn. A few minutes of work with a bore gauge and micrometer will tell which it is.

If one head bolt insists on stripping, the threads in the block are bad. That can be fixed with a thread insert.

But are valve guides and stems the same? With the piston or bore being like that, would that cause blow-by

[jlevie]

But are valve guides and stems the same? With the piston or bore being like that, would that cause blow-by

If the wear was in the piston, the affect on blowby would be minimal, but if the wear was in the cylinders it would increase blowby. Or if the rings are bad you'd have increased blowby. Worn valve guides or bad seals will also increase oil consumption.