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Thread: Piston and head damaged with small holes,what to do? sr20det

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2020-11-16 13:10:56
Piston and head damaged with small holes,what to do? sr20det
hello guys.
I bought a 1996 200sx s14 sr20det project for a good price..And the previous owner said the pistons needed a change. but it looks like the valves have been changed after the the damage to the head and piston since it does not have the same little holes as the rest of the head. In other words some previous owner have just ignored the damage,so i wonder is it not that serious and the engine would run fine?
Do i need a new head or can it be saved by me(what can i do?) or a machinist? any suggestions what could have happen to make the damage?
All the other pistons are fine,only the number two piston and head is damaged..
PS:the holes does not go through the piston
Here is some pictures..

Last edited by BenFenner on 2020-11-16 at 13-45-52. Reason: Remove accidental hyperlink.
2020-11-16 13:49:08
As long as the valves and piston rings seal, you should be good. You also don't want any sharp protrusions in the combustion chamber, as they will be hot spots which can easily cause pre-ignition. That piston looks really bad for pre-ignition, but it's hard to tell from the picture.

You should probably replace that piston, and file/grind down the sharp areas of the head to avoid any hots spots. You could file/grind the piston too if you need to save money.

Ideally, obviously, you'd want a new piston and head.

I've never seen anything like that. It's like someone hammered a torx driver into it on purpose...
Last edited by BenFenner on 2020-11-16 at 13-52-45.
2020-11-16 15:08:03
ok,thanks..the holes are not very sharp and probably have been smoothed out already..:-)
2020-11-18 15:25:15
I see stock pistons on sale once in a while which tells me it is an option but I wouldn't know the pro's or cons. It tells me some people have use for stock pistons so that means no bore but if that will work, ask BenFenner he probably knows that stuff

Originally Posted by mikkime
ok,thanks..the holes are not very sharp and probably have been smoothed out already..:-)

It is either that or it will fail harder sometime. You are boosted, it is already hard to learn or find how physics are at ten bars and still anything uneven and it might be smoothed but not even (imagine fresh and very old craters on our moon) you might burn hole in piston or if you are unlucky some metal part go fly around that kills engine that much a second hand is best option. What Ben just said is more likely and have a look at detonation you don't want that and you can't hear it happening, kills engine just as much second hand is best option so wise decision is to get piston like the other three and don't WOT it before this is restored to a safe condition. I just hope you will have compression you might expect from it with a used piston or else you will need four and a bore. Also, the latter is just the by the book repair and more costly and a bit more work but not more hard to do
Last edited by richardwbb on 2020-11-20 at 13-33-16.
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