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I am in the process of building a forged shortblock. My measurements came out very strange for the cylinder bores. Wondering if anyone has seen this happen?

My block is stamped 222222. 17k miles, perfect crosshatch.

According to the service manual my bore sizes should be 95.51-95.52mm. However my bore gauge read 95.55-95.57mm on all bores. Yes I triple checked. I thought my cylinder liners were worn out BUT…

Even stranger is that my stock pistons measured 95.52-95.53mm which is perfect for the stock piston clearance of 0.03mm!

Although all measurements came out bigger than than the service data, the clearance is still spot on for stock components.

However with forged Mahle drop-in pistons, the piston to wall clearance becomes too big, 0.1-0.12mm of clearance.

Something is wrong with my shortblock in a very strange way.

Should I drysleeve the block? Or custom order bigger pistons?
 

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GuiTaR
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From what I've seen some of the big boys in the GTR world say, I would not sleeve an OEM block. Billet is a different story. Apparently it's just very difficult to do properly in order not to weaken the block substantially.

I'm not a builder, so I can't really offer advice on very specific PTW clearances.
 

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You can safely dry sleeve these blocks no problem. Any competant engine machine shop could do it. Look on Darton's site. They have an approved installer list.
 
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