6 replies to this topic

[coopdog]

well the story is im getting a 998 block rebored and i was supposed to pick it up today,
i just had a call from them and they said they had trouble getting a piston off but got it in the end but when they tried to get one back on he said "it went ping like a carrot" god know what that means :L
so i was just wondering how hard is it to break a piston?

[HafMan]

I would of thought very hard. my dads old company use to machine them for a race team and they were solid.
What broke on it though?

Edited by HafMan, 25 May 2012 - 10:15 AM.

[Ethel]

Pistons can distort, but that's why you'd get a machine shop to fit them to the rods with the correct tool and means to heat them. Sounds like they might owe you a piston, if they didn't warn you of possible failure beforehand - I'll take that back if you supplied the piston and it actually has broken up because of a pre-existing fault rather than being abused by them.

[ibrooks]

Getting a piston off what? I'm guessing it went pop whilst they were pressing a gudgeon pin in. Unless there's a manufacturing defect in the piston or they did something wrong it shouldn't have happened.

I'd assume this was a new piston if they were boring the block?

Iain

[coopdog]

yeah the pistons are brand new, got them from mini spares and they got delivered stright to the shop, he did say hes getting a new one as its there fault they broke but it does seam a bit weird :/ shall i call minispares or leave it?

[oli8925]

Funny this should come up, I'm having discussions on the Viva forum about the very same thing, although it hasn't happened yet. I'm a noob when it comes to engine rebuilds and I'm using a company called Dartford Rebore & Engine Centre that was recommended to me by ML Motorsport. I want the bottom end lightened and balanced, yet engine shop said they don't think it's a good idea as it's iffy to do it with the pistons on the con rods, and that if you try to separate them they often go pop/crack/split or something along those lines. Although second hand the pistons are almost new and at first glance look in very good condition, they're also Hepolite and unavailable new, the only new pistons I can get are Sheepbridge and I've been warned they're not the best, so I'd like to try to use them.

[racingbob]

Funny this should come up, I'm having discussions on the Viva forum about the very same thing, although it hasn't happened yet. I'm a noob when it comes to engine rebuilds and I'm using a company called Dartford Rebore & Engine Centre that was recommended to me by ML Motorsport. I want the bottom end lightened and balanced, yet engine shop said they don't think it's a good idea as it's iffy to do it with the pistons on the con rods, and that if you try to separate them they often go pop/crack/split or something along those lines. Although second hand the pistons are almost new and at first glance look in very good condition, they're also Hepolite and unavailable new, the only new pistons I can get are Sheepbridge and I've been warned they're not the best, so I'd like to try to use them.

yes i had the same when getting my engine balanced

the block was honed and rings i said can you balance the pistons and rods

they said a chance of breaking a piston, i said do what you can then with pistons on