Piston Damage in 2 Cylinders- Should it replaced?

[philly90tsi]

Make a Long Story Short...... I blew the rocker arms off the intake side, Pulled the head off all 16 valves were sh!t!!! 2 of the 4 Pistons have damage from the valves smashing into them. Is that Floating valves? Not Sure....But they are little gouges. Will that affect performance>?

Also is it worth having my head done and not the block? I have a 5 angle valve job, HKS 272 cams, Findanza Gears, New Lifters, 1 mm Valves.

Thanks for everyone's input!! You made this experience easier to get through!! Even Know i had my dsm for 1 month and blew all 16 Valves its been a blast!

 

[NOSLO2PT0]

Make a Long Story Short...... I blew the rocker arms off the intake side, Pulled the head off all 16 valves were sh!t!!! 2 of the 4 Pistons have damage from the valves smashing into them. Is that Floating valves? Not Sure....But they are little gouges. Will that affect performance>?

Sounds like your timing got jacked up. Floating valves is from revving the engine too high. And in order to float the valves on a stock head, you need to be running some 272's or bigger, and spinning them well past 9k on a stock valvetrain. Otherwise, the stock valvetrain is very stout and can handle some abuse. As for the gouges in the pistons, if they aren't too bad, just take a dremel and smooth em down to make the edges of the gouge flat with the piston top. You don't want any raised spots, which create hot spots.

Also is it worth having my head done and not the block? I have a 5 angle valve job, HKS 272 cams, Findanza Gears, New Lifters, 1 mm Valves.

If you got 2 jacked up pistons, might as well just build the block while ur at it.

 

[philly90tsi]

Here is a Pic

 

[Daveed]

This is pretty much what mine looks like right now. How do you tell if a piston like this is reusable?

 

[Jst4Cyl]

The pics don't look that bad to me. But, the metal shavings could have ate in the cylinder walls depending on how long it was ran that way and how big the pieces were. I'd say that a freshen up wouldn't hurt for sure.

My thoughts over the rebuild is go for it. Do it right once and enjoy it twice as long. Do your research and as I just told another guy set your budget, goals (hp wise, time wise, daily driver,track car,etc...etc...). And document it all so you can look back on it and see where it was and how far you have come. Helps alot as a motivator when you invest $5,000 to $6,000 and still don't have it complete

BTW, you're lucky that you still have piston tops, if the valve heads would have smacked hard enough you would be looking at more work. Sounds to me like something faulty/failure in the timing. If you were at a high rpm then more than likely you would have seen something like this by the time your pistons came to a stop.

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[Daveed]

Thanks for the info. Nice pic there WTF.
My tensioner failed at idle in the driveway and the belt slipped a few teeth off as it loosened up. Idle got rough and low then it started clacking then died. Not much damage and the valves are barely bent. Enough though that there is zero compression. After looking carefully at the pic I can say that my damage is quite a bit less and without chunks of aluminum.
As for goals for the car. Thats actually a very good suggestion. I hadn't really thought about it too much yet.

 

[tkelly27]

I re-used my pistons with more damage than that. Then the timing belt broke for the third time (the first two were with the previous owner) and the piston split in two. had it not, i would have run 'em again, just to see what happened. : )

 

[Jst4Cyl]

Thanks for the info. Nice pic there WTF.
My tensioner failed at idle in the driveway and the belt slipped a few teeth off as it loosened up. Idle got rough and low then it started clacking then died. Not much damage and the valves are barely bent. Enough though that there is zero compression. After looking carefully at the pic I can say that my damage is quite a bit less and without chunks of aluminum.
As for goals for the car. Thats actually a very good suggestion. I hadn't really thought about it too much yet.

Hey no problem, feels good to help someone else.

My first DSM was a N/A 1G that had jumped a tooth or two and bent the valves but I heard the valves slapping and knew that it was over so therefore I just rev'd out 1st gear and let her pop.I didn't really care at that point. I'll see if I can't find the pics of the pistons, err I mean rings. Because that was about all that was left.

Yeah, this is the best time to start a build but also the worst. Christmas spending being the bad part, and the good part being winter IF you have a garage and time for the build. Good luck with it all and keep us updated.

 

[silver bullit]

Mine looks the same way, as long as the pistons are not deformed or pressed into the cylinder wall, you should be fine.

I would clean the piston tops and check for any cracks or deformation. I am also going to file the high/sharp spots down so the are not gonna become high temp spots when the motor is running.

The only reason i am doing the same to mine is cause i just rebuilt it 6-7k ago.

 

[BUCK]

As you failed to Drain the Coolant prior to jerking the Head & contaminated the Oil Pan & Motor passages you may as well at the very least drop the Oil Pan & check out Rod Bearings, Rings, etc... as you do a good Flush - I'm sure you've already done the BSE although I didn't see that on your Mod list - If not now's the PERFECT time for that too - Good Luck