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Pistons hit valves
Posted: Fri Apr 12, 2013 3:14 am
by bc
Timing belt broke so pistons hit valves. Would you reuse pistons that have a valve stamp on them?
Re: Pistons hit valves
Posted: Fri Apr 12, 2013 3:16 am
by bc
Here's cylinder #1
Re: Pistons hit valves
Posted: Fri Apr 12, 2013 8:58 am
by 82vdub
That looks like a really hard kiss. I'd recommend that you have a machine shop dye test the pistons to see if they can find any cracks, after you meticulously inspect the piston yourself. It also looks like your piston has some errosion from a dripping injector. Pull it out and inspect everything carefully and make a decision on whether to get a machine shop involved or just find another set of pistons.
Re: Pistons hit valves
Posted: Fri Apr 12, 2013 1:00 pm
by bc
It's hard to see from the pic, but the valve smashed part of the edge of where the fuel mixes on top of the piston. I'll take a closer look.
Thanks again!
Re: Pistons hit valves
Posted: Fri Apr 12, 2013 4:14 pm
by TylerDurden
You might check the piston protrusion.
Re: Pistons hit valves
Posted: Fri Apr 12, 2013 4:58 pm
by Quantum-man
If you look closely you will see concentric rings. No rings on the valve face, so it's not one big thump but many smaller thumps; at least until the belt gave out.
As per Tyler; bring up piston to TDC to check for protrusion reduction on this particular piston...
If none apparent, then rod fine, or near fine.
Check true depth of crater, as it may be less than it looks. Remove crater ridge then play on....
Re: Pistons hit valves
Posted: Mon Apr 29, 2013 6:42 am
by CoolAirVw
it would be ok to reuse, but you'll need to measure piston protrusion to make sure the rods are not bent. Also you should pull the piston out and make sure no metal is mushroomed from the impact and going to scratch up the cylinder wall.
Re: Pistons hit valves
Posted: Mon Apr 29, 2013 1:47 pm
by bc
The engine rotates smoothly by hand. I still have to pull the pistons for inspection. Thanks for the tips!