Should i replace these pistons and rings (with pics)

nyone · Oct 22, 2019

What was the compression before tear down? Or did you just jump in head first into the engine?

Usualy black snoke is unburnt fuel. This can be caused by many issues. Low compresson, not enough air getting to the cylinder and many more.

Did you take off the exhaust manifold? Is the soot/black stuff mostly on one cylinder?

blakester · Oct 23, 2019

Alight so maybe someone at some point threw a few big CAT stickers on the machine. The engine is definitely Mitsubishi, ( Mitsubishi K3E 1.05L disel engine). The parts I ordered (rings and head gasket) fit as they should. I suppose I should shift my search to the engine and not the machine type for the service manual. Nyone I did not check compression before tearing down, a step which I am regretting. But all 3 cylinders looked to have about the same amount of carbon build on up them.

blakester · Oct 23, 2019

http://www.boatservicehaarlem.nl/mitsubishi.pdf I found this, but it doesn't list the K3E which is the engine type I have.

blakester · Oct 23, 2019

Ignore that, it's listed below the other types.

nyone · Oct 23, 2019

Get your self a bore gauge. See how out of round the cylinders are. Or put the head back on and do a leak down test.

ericm979 · Oct 24, 2019

Also get a micrometer to measure the pistons so you know if they need replacing. You'll need a shop manual with the specs. If you can't find one for your engine, often a similar size and vintage engine from the same manufacturer will have similar specs.

Bayfisher · Oct 24, 2019

the pics of the pistons are way to large, a good reusable piston will have oil retaining ridges around the skirt of the piston, to chk
the cyl to piston clearance without instruments position the piston 1/2" down the bore correctly clocked as when running, use a narrow blade feeler
gauge and measure the clearance on 12 and 3 o-clock position at the skirt and divide by 2, most wear will be on the skirt.

if it was me i would replace the pistons.