Can a Fiat 128 1100cc 80mm cylinder head be converted to use on the 1372cc Uno Mk2 block?
I am searching for new 80.5mm 14 bolt cylinder head with no luck.
This is for a non turbo application. I want to use twin Weber carbs.
I've never done this to an open deck block before, but on a closed deck block a 10 bolt head on top of a 14 bolt block will have oil and water galleries (very close to) intersecting, as shown in the picture below.

The open holes where the 4 x small M6 bolts go are very very close to the water jacket and oil return gallery, I believe there is not sufficient material width bridged by the gasket to create a seal with enough integrity to be failure proof.
20221004_105202.jpg


look how close the witness marks show the gap to be...
20221004_105202.jpg


Ok, sure you could thread something into the hole to effectively make it solid, but that would require fitting studs and bottoming them out, then decking the block face to make the top face of the (now machined down) stud absolutely level with the block surface. Any gap, no matter how small, would be zero clamping force on the gasket at that point and likely to leak.

You wouldn't necessarily notice a leak here either, you might just lose pressure into the crankcase and without pressure over the cooling system the boiling point would be just 100C, and as the system runs at 90C normally, that's not a lot of headroom. Any water vapour that found its way into the crankcase would evaporate off as the oil temp is usually running above the boiling point of water so you probably wouldn't see it, but my guess is you'd be chasing a mystery overheating issue.

SteveC
 
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