Turbo m20 question

[cynthiabartel]

I am in the process of turboing my e30 and have placed a camera inside the cylinder walls and noticed lots of scoring and small effects of piston slap. I now know that I am going to have to either sleeve or find a whole new block overall. my original plan was to only do the top end and not the bottom but now a lot of people are recommending me to do upgraded pistons and rods assuming that there might be more problems in the bottom end of the motor. Is this needed or will the bottom end hold 350HP.

[It's Soda Not Pop]

If it were me I'd have a machine shop look at your block. Then go from there. Maybe a simple rebuild (bearings and rings etc) will work. Better safe than sorry. Unless you don't care then send it.

[TobyB]

If the bores are damaged, then yes, you'll want to bore the block and use larger pistions.
At which point, forged pistons are essentially the same money, and can be made however you like.
M20 journals tend to be tough, so take the engine apart before making any assumptions.

Rods- well, at your power level, the stock rods are pretty stout. However, with custom pistons,
a longer rod is possible, IF you want to go down that rabbit hole. And then, more strength isn't expensive...

My advise-
turbo what you have, and get it to work. This is a big project, and mistakes at this point
have the very real possibility of grenading whatever lump you're working with, so why grenade $4500 worth of new parts?
Once it's working at gentle boost levels and you're sure that you have fuelling, timing and cooling under control,
then you can decide whether to rebuild your engine, or find a spare to prep.

t
always has a few spare engines in various states of decrepitude.

[digger]

How does the engine run currently (or when it last was running)?