Pistons have dents?

[BurnBarfield]

Okay, well I just purchased a '95 TSI because it had a spun rod bearing. The guy mentioned having had the head rebuilt recently but didn't say anything about it having jumped time/bent valves, etc...

Well, I was going to pull the head off as I planned on reusing it, and then pulling the block out separately. I did so tonight, and when I pulled the head off I realized that the pistons have divots (sp) in them. Now I am trying to determine if it had jumped time before and then the head was rebuilt and the pistons were left alone, or was this more recent...

I couldn't visually tell if the valves were bent, but I realize that it can be deceiving. Is the only way to tell to pull the actual valves out or to actually get it pressure checked? If there is some way to tell at home, then I would be very gracious to know.

Thank you for reading,
Aaron

 

[Boo5t_Addict]

Oftentimes pistons have valve-reliefs built into their tops, just as a little bit of added protection against piston-to-valve contact.

 

[moto x]

is it in the center of the dome or around the edge

 

[19Eclipse90]

Don't pay any mind to the chips in the side of the piston there...

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You mean like those on top? They are supposed to be there, don't worry about it. Do note that this is a piston from a 6g72 motor, not a 4g63, so yours won't look exactly the same.

 

[BurnBarfield]

It is very comparable to what you have in your picture. I am taking the head to get decked and cleaned in a few days, so I will have them pressure check it to make sure they aren't bent, but you have taken away some of my worries.

Thanks guys, I will let you know how it ends up turning out.

 

[stealth mullet]

a good sign of the valve making contact with the piston is there would be fresh witness marks. the valve, if indeed is making contact with the piston, should have taken off a layer of carbon off the top, exposing clean metal.

 

[JayRolla]

Take a picture and let us see the pistons. Usually the pistons are fine when the valves bend. Sometimes you need to sand out some of the hot spots.

 

[BurnBarfield]

I am not worried at all about the pistons, I have a new block going in, but this head was just rebuilt a few thousand miles ago.. I just wanted to know if the valves may have become bent. There are no fresh markings through the carbon build up on the pistons. The marks are covered in carbon buildup.

The head will be going to the machine shop monday to get looked over anyways.

Thanks again.

 

[19Eclipse90]

Was the timing correct before you pulled the head?? If so, why didn't you perform a compression check before going through all this work? That would have told you if you had bent valves or not, free!

 

[BurnBarfield]

Timing was correct.

The reason I didn't do a compression check, was because I was not worried about the head as it had just been rebuilt, and I was pulling it off to swap it onto the spare block that I am about to put in.

 

[19Eclipse90]

Honestly, if the motor was running well before you pulled the head, I wouldn't worry about the valves. And I'm pretty nit-picky about doing stuff once/right. But if you do question them, better to get it checked out first.

 

[BurnBarfield]

I am extremely nit picky myself, before I start anything I have to know every last possible step memorized.

The head is getting cleaned up (tanked?) at the machine shop monday and possibly decked down a little if it needs it. They said it would be 15 bucks more to pressure check since it is getting cleaned anyways, so I am just going to have it checked for peace of mind.

It was in time when I pulled it off, and other than the knocking rod it ran fine.

 

[BurnBarfield]

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[Defiant]

I know you're not really thinking of bumping this thread.

Get us pictures of your pistons.

 

[BurnBarfield]

In my last post, I put pictures.. Can noone else see them?

I will try to do so again in a moment.

 

[USMCFieldMP]

I can see them...

 

[babell2]

Yes those are normal. Don't worry