[Healeys] Hardened seats in a cast iron 100 head

[kags at shaw.ca]

Michael:
 
I have done it successfully on my BJ8 head, which admittedly might be a different kettle of fish than the 100 head.
 
In the mid 80’s – at the time that leaded fuel was being phased out, we discovered a crack between 2 adjacent valve seats when doing the engine’s 1st rebuild.  It needed those 2 seats done, and since everyone was worried about what unleaded fuel would do to our engines, I made the decision to install hardened seats on all 12.  I started the engine out on unleaded fuel, and never did run leaded.  Normal valves – hardened were not available at that moment.
 
The engine ran beautifully for approx. the next 100,000 miles, at which point we did another rebuild in conjunction with a ground up restoration.  When the engine was taken apart, very little wear was evident in the head – the valves were still good, only needed a normal careful grind.  We were pretty surprised that the head looked that good after that mileage.  Note also that sintered bronze valve guides were installed as well – apparently a no no according to some people.  They must have been sized perfectly because there was no apparent wear to either the guides or the valve stems, and they were left as they were (other than the grind).  The 2nd rebuild now has appox 25,000 KM’s on it with no issues.  It’s a sweet running engine in stock form.  (yes – I scored an OE  metric speedo head several years ago and run it just to be obtuse!)
 
Earl Kagna
Victoria, BC
BT7, BJ8
 
 
 
From: Healeys <healeys-bounces at autox.team.net> On Behalf Of Michael Salter
Sent: Sunday, August 25, 2024 7:44 AM
To: healeys at autox.team.net
Subject: [Healeys] Hardened seats in a cast iron 100 head
 
I am still using cast iron heads on both my 100's. Amazingly neither have serious cracks as are so common on these.
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. 
I'm contemplating installing hardened seats in one. 
Hase anyone done this successfully?


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