Scored pistons
Posted: Fri May 13, 2005 11:23 am
Hi all,
Around 30,000 miles ago I did a reconditioning job on my standard 1089 engine. Crank was reground, bored out +20 oversize, new pistons, and a full set of new bearings, gaskets and stuff.
I recently did something bad. It had an overheating problem, and late one night it started over heating. Instead of parking on the hard shoulder, I limped it off at the next junction, which was about 6 miles away. Although it got me out of trouble, it was making a awful noise, and the oil was literally boiling on the outside of the block. I think a modern car would have just stopped/burst into flames!
I knew the overheating problem was because there was a slight depression on the block face between cylinders 3 and 4. It had recently blown 3 head gaskets and I knew this was the forth. So the whole thing had to come out anyway. It also needed a new clutch.
On pulling it all apart, the crank is still very good, and the main bearings were okay. The big end shells were more worn around the centre (cylinders 2 and 3), but were not as bad as it sounded.
The plan now is to get the block skimmed and re-honed and use the existing crank as it is.
The pistons are generally in good condition, with the rings fully intact, and no noticeable areas where the gases were blowing past. BUT... there are score marks down the sides of the skirt.
Can I re-use these pistons and rely on them? Would I be right in assuming the job of the skirt is just to keep the piston aligned in the bore, and so scoring (due to it getting too hot), will not cause any future problems? Surely the piston rings and crown are doing the real work?
Does anyone know how tolerant the A series is to having the block skimmed? (Is there room without taking the top of the pistons too, which I don't like the sound of!?)
Any advice would be appreciated.
Cheers,
Chris.
Around 30,000 miles ago I did a reconditioning job on my standard 1089 engine. Crank was reground, bored out +20 oversize, new pistons, and a full set of new bearings, gaskets and stuff.
I recently did something bad. It had an overheating problem, and late one night it started over heating. Instead of parking on the hard shoulder, I limped it off at the next junction, which was about 6 miles away. Although it got me out of trouble, it was making a awful noise, and the oil was literally boiling on the outside of the block. I think a modern car would have just stopped/burst into flames!
I knew the overheating problem was because there was a slight depression on the block face between cylinders 3 and 4. It had recently blown 3 head gaskets and I knew this was the forth. So the whole thing had to come out anyway. It also needed a new clutch.
On pulling it all apart, the crank is still very good, and the main bearings were okay. The big end shells were more worn around the centre (cylinders 2 and 3), but were not as bad as it sounded.
The plan now is to get the block skimmed and re-honed and use the existing crank as it is.
The pistons are generally in good condition, with the rings fully intact, and no noticeable areas where the gases were blowing past. BUT... there are score marks down the sides of the skirt.
Can I re-use these pistons and rely on them? Would I be right in assuming the job of the skirt is just to keep the piston aligned in the bore, and so scoring (due to it getting too hot), will not cause any future problems? Surely the piston rings and crown are doing the real work?
Does anyone know how tolerant the A series is to having the block skimmed? (Is there room without taking the top of the pistons too, which I don't like the sound of!?)
Any advice would be appreciated.
Cheers,
Chris.