Bought a built sr20 and there are scratches on the wall!! PRO ADVICE NEEDED

[filluptieu]

So I just picked up this motor which was done by a machinist and noticed the scratches. The guy I bought it from told me that when the machinist installed the piston one of the rings broke and scratched the wall. the scratches are minor however you can slightly feel it with your nail. it isnt gouged but very slight. The pistons are CP and are new. The cylinder is honed from what I can tell.

In the end he told me that the shop that did it said it would be okay. I really need to professional advice. Please guys give some thoughts

http://pic90.picturetrail.com/VOL2335/11805834/21247457/403654533.jpg
http://pic90.picturetrail.com/VOL2335/11805834/21247457/403654532.jpg
http://pic90.picturetrail.com/VOL2335/11805834/21247457/403654531.jpg

[TheWolf]

if I was building a 24 hours of lemans car.. I would just touch it in the hone.

short of that. let it ride.

[Kingtal0n]

you need to find out if it was run like that or not. If it was never run, you can seat a new set of rings on it. If it was run, with another set of rings, your brand new rings may not give the performance you desire.

Its too bad about the scratch, but what can you do? Either you have to use it like that, or bore it bigger in the hopes you exceed the depth, or change blocks. You cant just weld a strip of metal down the side and sand it smooth.

[Chrischeezer]

wow... that's terrible I can't believe a machine shop would let that go.Its obviously been machined already imagine how bad it was before.
If its deep enough to feel a scratch with your nail its going to effect performance, this is a series of scratches... pressure will leak past the rings. After extended use that part of the block with deform the ring/landing and piston, don't assemble it

[godsmack]

personally i would would get a good machine shop to sleeve it. i wouldn't trust it. it might work with no problems and no leaks but i think that it'll leak and get worse.

[stilmissmysti]

What is the bore at now you may be able to over come the scratch without sleeving the block

[MadScientist]

I agree with Woft, re-hone and done...

[ForceFed]

If it will catch your finger nail and the piston to wall clearance has already been set, chances are the amount you'll have to hone out will bring you a few thousands over. You might want to step up to .5 mm over pistons

[Slammed Assassin]

I personally would get it redone. Just to have the satisfaction and not be paranoid about it.

[Davidna2fi]

If it will catch your finger nail and the piston to wall clearance has already been set, chances are the amount you'll have to hone out will bring you a few thousands over. You might want to step up to .5 mm over pistons

+1 ... too deep, honing it will only cause a larger ring gap and also possibly piston slap and oil consumption issues. Ring gap is crucial, spec is spec, DOUBLE spec is way too much and those little scratches will make it double if you try to hone it out. I put money on that.:cops: