Blew a rod, what did this to the piston?

[tiger]

Hey I was just curious what caused these markings on the piston, bought a 500 dollar lx 240 with a knock and tried to hump it home but blew a rod out the side and i just removed the head and discovered these markings on the piston

[wa-chiss]

ats a new one on me.........

[mrzabala]

Looks like that piston hit the the valves. Could be the the timing was off and the chain jumped a tooth(s). Over revving, oil starvation just some things that could cause it. Check underneath your your cylinder head where the valves seat.

[tiger]

hey, yeah that's what another friend suggested...that it hit valves... here is a picture of the underside of the head.



valves all look normal.. none look bent but i dont have the tools to remove the valves.. :/

[mrzabala]

Bring a light into the valve spring and see i you can see the valve rod. Only way you can have those markings on those pistons is the valve striking as I see the circular half's on opposite sides of the piston. Leaning towards over revving and or over heating/lubrication if the connecting rod shot out the side of the engine block.

[tiger]

I have been inspecting the valve surfaces on #3 and they look untouched and are all seated properly.. they do not hang open at all. I'm trying to make sure this head is O.K. to sell to someone. I will try looking for the valve rod to see any damage. I'll let you know. Thank you.

[yellowcar]

Could be from the piston dropping down too far in the cylinder when the rod went

[tiger]

hey that could be something cause I know it couldn't have touched the valves because there is no evidence of piston an valve contact.

[wa-chiss]

^ true, I would bet it's not from the valves kissin the piston cause there's only 2 marks on the piston but yet you have 4 valves. There would be 4 markings if they hit. <-- yeah I know............ we todd did math.

[tiger]

i found out that it was from ouching the underside of the head, yhere eare those half moon markings...

[wa-chiss]

Why didn't I think a dat.

[Crichton]

no 100% sure but it looks like the top of the pison met the bottomof the head. But as I said not 100% sure. AN the only reason I sugest that is because. I am currently in the middle of the Cyl head rebuild an have notice that. The head as 2 spots that are like a ledge. an from the pic thats what it looks like to me. So maybe a streched rod?

[rb25drag]

To check the valve seats in the head poor gas down the ports. If they leak there bent if they stay dry there good.

[tiger]

that's what I figured.. I looked at the bottom of the head and saw that.. are you rebuilding the one i sold to Tam?

[devil_child]

bottom bearing slipped leaving a roughly 1mm room of play causing the piston to hit the flat quenches on the sides of the chamber.

[tiger]

ah, that makes perfect sense.. I was looking at a bearing and one had actually melted into the connecting rod.

[Crichton]

dude sorry to hear that!!!! Hope you have some luck finding a new long block. Give a shout if i can help ya out.

[tiger]

oh and if anyone needs a block, I have an extra