Hi All, engine out, pistons removed, part of the piston skirt has broken off immediately below the bottom ring, so hence the oil burning smokey engine, but all the spark plugs are fouling up, oily deposits as far as I can make out, so would this broken piston be the fault. All the bores are clean, no wear ridge at the top of each bore. Any advise please.

Thank you in anticipation.

Regards Tom

 

Would be better if you could post a pic of the broken piston.

As for the engine fouling up all the plugs and burning/smoking 

engine, indicates that all four cylinders have a problem.

 

Their are only a few reasons an engine would burn oil

1. Worn piston rings and bores

2. Worn valve guides & seals

3. Blown head gasket between oil gallery & combustion chamber.

 

If the engine has done a high mileage and is old then it's gonna need a full

rebuild including the head (valves & guides replaced)

Thank you for the advise, have asked  the mechanic to , change 4 pistons and rings as well as big end shells, oil and filter, gaskets, I bought these, this morning as well as a new timing belt.

He insists the head and valves and seals are ok.

So the proof of the pudding will be in the eating.

Regards Tom

It would be stupid not to change the valve stem oil seals and lap the valves and skim the head while the head is already off.  Do it right or do it twice.  Don't listen to  your mechanic.

2 hours ago, tomtaylor1 said:

Thank you for the advise, have asked  the mechanic to , change 4 pistons and rings as well as big end shells, oil and filter, gaskets, I bought these, this morning as well as a new timing belt.

He insists the head and valves and seals are ok.

So the proof of the pudding will be in the eating.

Regards Tom

If head is off you MUST lap the valves in and change the seals...On your engine will take an hour..Your "fitter" will NOT know if the valve seats are OK unless he has LOOKED at them....

20 hours ago, tomtaylor1 said:

Thank you for the advise, have asked  the mechanic to , change 4 pistons and rings as well as big end shells, oil and filter, gaskets, I bought these, this morning as well as a new timing belt.

He insists the head and valves and seals are ok.

So the proof of the pudding will be in the eating.

Regards Tom

As others have already stated it seems that your repairing the engine instead of rebuilding it.

 

Are you reboring the cylinders and fitting new oversize pistons or fitting new o/e pistons in to old bores?

 

How does your mechanic know the condition of the:

Valve guides? 

Stem seals?

Valve seats? 

Has the head been stripped for inspection?

 

Are you regrinding the crank and replacing the Big end & Main bearings OR just 

replacing the Big end bearings only with standard size? 

 

I find it amazing that a piston break up has not caused damage somewhere, plus why did the piston break up..Faulty casting or something else.....

Pistons usually break due to excessive bore wear causing piston slap and eventual failure, the bits drop into the sump very rarely cause any other damage, just rebore/resleeve fit new pistons and off you go.

3 minutes ago, MYKTHEMIN said:

Pistons usually break due to excessive bore wear causing piston slap and eventual failure, the bits drop into the sump very rarely cause any other damage, just rebore/resleeve fit new pistons and off you go.

Seems the bores are OK........

Just now, transam said:

Seems the bores are OK........

I doubt that very much

Sorry for not posting an update, I am still waiting for the mechanic to fit the engine back into the car.

Took the cylinder head last Friday to machine shop, had the head skimmed, valves checked and lapped in, valve seals replaced, cam shaft checked.

Did check the fit of the new pistons in the bores, no side ways movement.

So as I say am still waiting, then the proof of the pudding will be in the eating.

Thank you.

Regards Tom