Author Topic: head differences?  (Read 1110 times)

Offline sinister polo

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head differences?
« on: January 25, 2010, 09:14:46 pm »
hi all i have a spare head of a nz engine and im just wondering if i can use it for a big valve conversion,
so that i can keep my car running while its being done!

am i right in thinking that the differences between this head and a g40 one are:double valve springs,sodium coated valves,
and different cam?

Offline poloeatonm45

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Re: head differences?
« Reply #1 on: January 25, 2010, 11:02:58 pm »
yeah all the 1.3 castings are the same

steve

Offline breadman

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Re: head differences?
« Reply #2 on: January 25, 2010, 11:14:25 pm »
I'm pretty sure all 1.3 injection head castings are identical.
G40 heads have the sodium filled exhaust valves, but I'm not sure they all have double valve springs. IIRC, some later castings were fitted with smaller I.D. valve guides.
I can't see any reason not to use the head off an NZ engine. It's worth checking that the threads in the top of cam bearing caps aren't damaged or stripped where you bolt the cam cover on. They are line bored at manufacture, so you can't just replace them. Also check for any hairline cracks between the valve seats and heavy pitting on the head face.
Hope this helps.
Richard.