Roald

Long story short.

Newly acquired vechicle smokes (oil) a lot after first drive (20 miles)

351 cleveland with 2V australian heads, roller cam, Keith Black hypereutectic pistons (Part # KB148). Rebuilt 13000 miles/3 years ago according to previous owner.

Leakdown tested the engine first and it had lower compression on 1 cylinder.

The local mechanic removed the heads and found this



No scoring/damage on the cylinder wall, fortunately.

We are guessing that maybe pinging causes it based on this info from the link below?

United Engine and Machine Co.

Later found out that the timing was set by the PO to 20 degrees initial timing with probably 24 degrees additional mech advance not long before he sold it. (has not been driven long with this setting)

The mechanic says he can change the one piston while the engine is in the car. There is no visible damage to the other pistons and he will check the valve and seats for damage also.

Is this an okay way to repair the engine? (no need to balance the rotating assembly when changing one piston?)

xdclevo

I have heard this is a common problem with that brand of pistons when piston to bore clearance is not correct. I personally would bin the rest and start again as its hart to really tell if the others arn't ready to go as well.

I have changed one piston once when damaged from a wiped cam, and found an exact brand one and all was good without balancing again.

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10.70 @ 125.00 on the black fun top
408 Cube Cleveland.

russxr67

That is not a piston to bore clearance problem as that part of the piston does not come into contact with the bore.

I would bet that the engine does not have enough ring to bore clearance . The top ring binding would have lifted the top half of the piston. Common problem on the KB piston if you do not follow the ring gapping recommendations.