just got my motor back from getting build and 2 cylinder wall scratch have scratch deep enough to hang a fingernail on. I have a 2000 block,they are straight up and down the wall, some are the length of the piston travel and the other scratchs are from half way down. is this bad i asked them why it was like that and he said its cause the new piston rings are breaking in, is that true or did he mess my block up. and how does the scratchs get there. he said he did a hone. please help me out i feel like i got ripped off. I do think he knows what hes doing cause he did finish schools a sams and was working at a perfomance shop building motor.

 

Scratches on cylinder walls from breaking in? Go throw a quarter stick in his shop.

 

im not a engine builder but i am almost sure that if u can hang ur fingernail on it i would say it is not good and him saying the scratch came from the rings breaking in sounds to me u need to take it back to him and make him pay u ur money back and then find a new engine builder

 

What will happen if i run the car like that

 

U think it will hold compression

 

put up some pics, then we could tell you more. scratches (light ones) are common on stoker motors, but not stock stroke rebuild motors

 

ya pictures are a must, if you think you can get the shot to correct the issue i would have it corrected. They might have to just do a hone or maybe more depending on the scratch.

 

File fit ring may not have been deburred enough on the end....have seen it many times before.

If you can grab a fingernail on it that is definitely no bueno.....

Pics as others suggested would be good here

Good luck....hopefully its something silly

-Tony

PS....But now is the time to address it for sure if it is an issue!

 

with the scratch, it will probably pass some oil and smoke. There shouldn't be any vertical scratches, just hone marks. I would take it to another machine shop and ask what they think.

 

truth, you have a lot more credibility to get the issue fixed now then in a few months when something goes bad.

 

Sounds like something may have been in the cylinder when turned over or he cracked a rtying when he was putting it together, definately would be zero scratches in there tho.

 

What Tony said. It is always the small details that take the extra time and make all the difference.

 

but it was only hand turned

 

Thats all it takes.

 

Also...if this situation was "normal" or acceptable why would only two cylinders be scratched and not all eight?

Bottom line....you may see some light vertical lines in a freshly machined block but they are only visual and veeery light. You absolutley can not catch a finger nail on them.

Thing about a block that is in good shape with 50,000 miles on it....you couldn't find a single vertical scratch that would grab your nail if the shortblock was properly put together and well maintained.

It sounds like you certainly have an issue (once again pics would help)....I wouldn't gloss over it and hope its nothing or that it will go away when you run the engine....it will only get worse quickly I assure you and the metal coming off the cylinder wall is likely embedding in the skirts of your aluminum pistons.....not good.

-Tony

 

they are stock pistons with stock replacement rings.

 

Here's pic of what my #1 cylinder bore looked like at 72,000 miles, (ignore where the valve introduced itself to the piston, that's an old scar). You can see where the piston scuffed the thrust side (is that correct?) of the bore. You can't really feel any of what you see except the dark vertical line. That you can feel with your fingers and can catch a nail on ever so slightly. I had the motor out and heads off due to a valve spring failure, but found this along the way.
http://www.flickr.com/photos/1qwikbird/5499759306/
After talking to a my local engine guy, it was decided to hone it oversize and start fresh. The motor still held good compression and showed no signs of this particular problem, but it was only a matter of time til it did. If you motor fresh from the machine shop has a scratch in the cylinder wall that you can catch a nail in, you need to have a nice CALM discussion with them and have them make it right, especially if turning the motor my hand caused the scratch.

Is the scratch fresh? Possible they were there and maybe they didn't clean up with the hone job? Just thinking out loud. I'd imagine for that to be the case the scratches would have needed to be pretty severe to start with? My bore in the picture cleaned up at .005, but we took them out to .007 so we could go with an off the shelf piston for my build.

For comparison sake, here is a shot of the adjacent cylinder where you can still see factory cross-hatch pretty easily.

http://www.flickr.com/photos/1qwikbird/5499164259/
Don't go forward until this is resolved. Good luck and post some pics.

Chris

 

here are some pics

 

You say you just got it back from the builder..... They took the pistons out and left the carbon **** stain on there and didn't clean your deck surface. Get a new builder Fu****g asap

 

Yeah I'm with ^^^^^^. They look like before the rebuild pics, not after the rebuild pics. I really hope the pics you posted are an attempt at humor or something because I don't see how a professional shop would let that go out the door as a finished product.

What did they do? Pop each piston out, run a ball hone up and down real quick, slap some new rings on and slam it all back together? Cause I'm betting if they didn't clean the tops of the pistons (bead blast), they probably didn't clean out the ring grooves all that well either and a ring hung up on the install. Don't know what else to say.

What did it look like before being "rebuilt"? What exactly did you pay to have done?

Don't go forward with that shortblock till you get some answers.