Fiat 1608 Head and 131 block interchangability

[vcg]

Hello,

I got a good question: Can an 131 head fit a 1608 block? And can a 1608 head fit an 131 block?

Thanks,

[Guy Croft]

Yes and no.

It will fit and there are no issues except for one. The 1608 head has a large coolant gallery at the front of the head that does not match the later 84mm block and will leak. It can be of course be welded up and refaced.

There is no benefit to putting the 1608 head on the 2 liter 131 unit, sure it has a small combustion chamber but only fractionally smaller than the early 131 head anyway, and I would want the late larger (deshrouded) 131 head . That said I would want the deshrouded and 43.5mm inlet valve 105/130/Delta/Prisma TC head. Sure the 1608 inlet valves are 42.7mm but they are going to be over 30 years old and may not be one-piece stainless like the later OE valves.

Please be aware that I am not a fan of the US style swap this-swap that philosophy because for me there is nothing that cannot be achieved with the raw material in front of me, in terms of combustion chamber mods, valve and port sizes, by careful work. And in the end I can get better and more quantifable results because I do the flowbench analysis.

GC

[vcg]

That's great, thanks! But what about the 131 head on a 1608? Will it fit the 1608 block without any modifications?

Thanks,

[Fiat CC]

From reading what Guy has just said, I would assume that you'll have the same leaking issues from the water gallery in the 1608 block with the 131 head on it. What are you trying to acheive by doing this swap, or are you looking for easier to get spare parts?
thank you,
Reuben

[SteveNZ]

That's great, thanks! But what about the 131 head on a 1608? Will it fit the 1608 block without any modifications?

Thanks,

Yes

[Guy Croft]

I'd be a bit cautious of doing that 1608 head on 131 block if the 1608 head has the same coolant gallery as the 1438 head I have here.

See photos

GC

[vcg]

I have fully understood that the 1608 head does not fit the 131 block without modification.

My question is now: can I safely put an 131 head (Ritmo 130 TC in particular) on a 1608 block without modifications?

Thanks,

[Guy Croft]

You will have to offer the head gasket from the 131 2 liter or 105TC block to check this coolant gallery thing, that's first. Then you'll have to check the piston to valve clearances, the 105TC valves are bigger, see GC Virtual Workshop.


GC