piston condition

[coldday]

timing belt broke on my 4cyl rodeo 1999
i'm posting photos from the worst pison and wonder if it is passable? thanks.





here is a picture too, of all 4 from top;
http://www.sierranature.com/pistons.jpg

[JustSayGo]

Smooth any sharp edges a little with a file, knife, or powered Scotch-Brite disc. You won't have a problem. I don't see enough damage to squeeze a ring land and cause the top ring to stick. There is no benefit in working on the pistons until they look new. Now your pistons have tiny valve reliefs just like many new pistons.

[Gizmo42]

I agree, clean it up some and try it. If it works ok and lasts then great. If not you end up with a rebuild or new engine anyways and havent really lost much except time.

Just dont put it together and try to pawn it off on someone. Not saying you would but some ppl do.

[redbug]

Hello,

This piston is not the concern here... It's the gouge in the cylinder wall (top picture) that I would be worried about.. The sleeve needs to be replaced (if there is one). The rings will not hold compression at the gouge... Hot gases will eventually blow by the rings and fry the oil up on they cylinder wall, no lubrication, friction, ouch.... If the gouge is as low as the oil ring you will be sucking up oil into the chamber on the intake stroke.... All in all, not a good sign....

[2000izusu]

yeah i saw that to but thought it was a piece of carbon hanging down (due to the shadow on the left). well coldday is it a gouge or carbon?

[rodeo02]

You could try to clean up the piston tops and cylinder bore. Hard to say how reliable it will be though. I've seen crashed pistons crack when put back into use. They are just thin aluminum.

Joel

[coldday]

thanks for all the input.

that's a carbon flake hanging down there, so my only concern was piston strength. I'm planning on ordering a rebuilt head ($425) and putting that on, as at least 1/2 the valves are bent on mine and an exhaust manifold stud is gone (was gone on it's own at some point... second new exh. manifold put on this car...) machine shop wants 372 labor and 7-15/valve so figured 425 was better. have to remove the exhaust cam to remove the head bolts on that side though, pita...

figured i'd just clean out the loose stuff/coolant drips and start ordering gaskets and tensioner/idler pullies which i want to replace.

what about oil pump? worth thinking about replacing? 137k.

thanks.

[JustSayGo]

Oil pump gears are just gears that pump oil. The will have little if any wear ever... unless hard metal goes through the pick-up screen to get to the gears. Replace the Oil pressure regulator spring. The spring controls the oil pressure and every spring made will break if it is flexed enough times.

[surferfletch]

I don't know if I could drive the vehicle knowing that a couple of the pistons were damaged like that. How long would you expect before that hot spot caused the piston to crack?

[JustSayGo]

As long as any other piston that was built with valve reliefs. There won't be a hot spot and the piston will not crack because it has dents hammered into it. The sky will not fall. Maybe you have already driven more miles than you know... but never knew.