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Re: Cylinder head rivet
Posted: Sat Dec 19, 2020 3:57 pm
by rpb203
I think the ‘pop’ rivit is a factory fitting.
However sure it will be confirmed by others.
Re: Cylinder head rivet
Posted: Sat Dec 19, 2020 5:12 pm
by CMC
The pop rivet was indeed factory fitted from approx. '88. I always assumed to distinguish heads suitable for unleaded fuel.
Re: Cylinder head rivet
Posted: Sat Dec 19, 2020 5:28 pm
by Spider
They used the rivet in the head and also on the blocks, for the Oil Pressure Relief Valve Vent drilling on the front of the blocks from about 85-ish. It was just a cost cutting measure, it can be replaced with the original Brass Plugs, though I tap them for screwed plugs.
(The unleaded heads did appear until 89 or 90).
Re: Cylinder head rivet
Posted: Sat Dec 19, 2020 7:34 pm
by whistler
I think the 12G940B heads were unleaded.