Advice - Boring 1.5 to 1.7 - Alfa Romeo Forum
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Hmmm Advice - Boring 1.5 to 1.7

HI all,

I have finally pulled down the 1.7 engine i bought for my sud, and the cylinders are pitted. I have searched and cant find oversized pistons.
I have 2 1.5 engines and want to know if one can be bored to suit the 1.7 pistons. I can see that the crankshaft and journals and bigends are the same size, but does anyone know if the casings are the same for 1.5 & 1.7 just with different sleeves, or is the cast different bore as well?

I am trying to keep cost down would rather this option than resleve the 1.7 block... unless anyone can tell me why this wont work????

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You can bore 1.5 to 1.7 but..... you have to be very careful how you will treat the engine because wter passages are too close to surface. So , if it s going to be for example a race car , there is a possibility that the block will crack. For daily use i dont think there would be a problem.
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I'm using a rebored 146 1.6 boxer engine block for two years now
(the cylinder bores was increased from 84 to 87mm) without problems.
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Originally Posted by jbyatt View Post
I have finally pulled down the 1.7 engine i bought for my sud, and the cylinders are pitted.
Hi JB - how bad is the pitting? Would re-honing the bores clear it?

If the 1.7 block is definitely U/S then another solution might be to fit the 1.7 crank into the 1.5 block. You retain the standard 1.5 cylinder bore, but the longer crank throw means that with special pistons you get a 1.6...

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Another difference between the 1.5 & 1.7 block is that on the 1.7 there are cut out machined into the main oil gallery inside the top of the block to give extra clearance for the longer crank throw - if you look inside your 1.7 block you will see what I mean
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