i should learn to leave engines well alone.

ok so i got another landy today.

took the head off and one of the pistons has an inprint on the top of it that looks like the swirl chamber has hit it, no other damage is apparent, any idea where to look for the cause of the fault first?

it did run and sounded ok, but smoked like a bastard.

hot spot damaged ,in place ,is it a circular mark ,not all of hot spot sits over bore as gasket holds it in place ,

hot spot is ok and in place, looks like the bit of it that is over the bore has left an inprint on the piston, circular but not a full circle abviously. no damage to hg either.

big or little ends worn ? hot spots shrink during use is it very loose and if cracked fit new ,any ridge on bore opposite cam side

no not loose and no cracks. whole head looks like its recently been refurbed.

yes it has a ridge with a slight burr on it, worse opposite cam but worn cam side also.

i will investigate further when i get a new gas bottle for the heater in the garage.

my manual advises not to regrind crank if worn, is this good advice or can they be reground?

two landys, one good engine yippee.

bit worn then ,may be mark from previous problem

jamesmartin said:

bit worn then ,may be mark from previous problem

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you could be right but i cant see why anyone would leave a ****ed piston in an engine, save a penny to spend a pound!

i dont know how bad it is ,but it isnt unusual with uncoated pistons to leave in if only minor damage to top ,i come across it alot ,where you can see work has been done so must have been known about

jamesmartin said:

i dont know how bad it is ,but it isnt unusual with uncoated pistons to leave in if only minor damage to top ,i come across it alot ,where you can see work has been done so must have been known about

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i dont know enough about engines to know how bad is too bad. i guess whoever left it in wouldnt have if it was that bad.

the whole trucks rotten and purchased with the idea of spending plenty of quality time twiddling in the garage.

just had another look at it.

you know how pre ignition on 2 stroke petrol engines starts to burn down the sides of the pistons, looks just like that on the point of the "v" thats on top of the pistons.

1 is v bad, 2 bad, 3 bad, 4 unmarked.