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Well, that wasn't OP's question. <br>
<br>
You can certainly get by without the inserts in a lower compression
engine that isn't run hard but, if you're doing a head job then why
not? The risk of cracking is legitimate, that's why you need a good,
experienced machinist to do it; a good machinist will recommend
against it if he's encountered problems with similar heads. <br>
<br>
<div class="moz-cite-prefix">On 8/26/2024 8:27 AM, Kees Oudesluijs
via Healeys wrote:<br>
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<p>In most cases hardened valve seats were/are not necessary.
There was only a small handful of engines that gave trouble
after introducing lead free petrol.<br>
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<div class="moz-cite-prefix">Op 26-8-2024 om 16:43 schreef Bob
Spidell via Healeys:<br>
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My dad had our BN2/100M's head redone--valves, guides, etc.--by
a local speed shop we trust (the machinist is a meticulous Kiwi
who Dad said got really excited when he saw 'Weslake' cast in
the head). Unfortunately, Dad isn't around to ask, but they
almost certainly installed hardened exhaust valve seats; it's
been SOP since, well, since lead was removed from gas. No
issues, and I had it out on the road a couple weeks ago. <br>
<br>
<br>
<div class="moz-cite-prefix">On 8/25/2024 7:44 AM, Michael
Salter wrote:<br>
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<div dir="auto">I am still using cast iron heads on both my
100's. Amazingly neither have serious cracks as are so
common on these.
<div dir="auto">I am really picky and don't particularly
like the different sound that a 100 engine with an
aluminium head makes so would like to continue using these
cast iron ones. </div>
<div dir="auto">I'm contemplating installing hardened seats
in one. </div>
<div dir="auto">Hase anyone done this successfully?</div>
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