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100 Cylinder head identification

Dougal

Senior Member
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Hi All, does anyone know how to identify a hundred cylinder head? When I bought my car it came with 3 spare blocks and 6 heads. I’m pretty sure one of the blocks is an A70 and one is a A90 from the bore size, but I’m not sure about the heads.
Cheers
Dougal
 
Hi Zblu
All have the same Weslake casting, can you explain what you mean about the "1/4" narrower on the face".
 
"When I bought my car it came with 3 spare blocks and 6 heads."
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That's about the right ratio.
 
"That's about the right ratio"
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It wold be nice if I knew if they were any good, I have just droped the heads of to be crack tested as the first stage in the keep them or bin them decision.

Anyone know how thick the head should be i.e how I can tell if they have any life left in them for skimming (Two of them have bad rust pitting)?

Dougal
 
In my limited experience, the A90 head as found on the BN1, BN2, has a rather thin deck to start with. Around .200" to .220". Not the same front & rear. This on a head that measures around 3.680" from top surface, (rocker gasket) to bottom surface. I would be uncomfortable skimming more than .010". In my opinion, a deck that was much less than .200" thick would be too weak. You can get a pretty good estimation of deck thickness by measuring from the gasket surface to the water jacket in some of the cooling passage holes.
D
 
They all say "Westlake"--even the Denis Welch AL head. And BTW I recently heard that an AL 100 head is being made in the US which brings to three (along with DW and SC)the number of suppliers--fascinating assuming they are selling only to the Healey market and a total run of 15K cars.
 
Dougal,
lets say the length of the head that faces the block is "x", then the width of the same face of the head is about a 1/4' narrower on the A70, they can be used as an interim measure.
The thickness from memory from the above face to where the rocker cover sits is about 3 1/2", so after the crack testing you may end up with a thin one, where as one of the others may be more suitable for rejuvenating
Dont bin the u/s ones, send them my way /ubbthreads/images/graemlins/smile.gif
 
Thanks Zblu, Will measure when I pick them up from crack testing. As for the cracked heads, you may need to help with the postage.....
 
Dougal, will do!,
Had mine welded up (14 cracks from mem), and had the face built up 125 thou to compensate for previous work by others in the past prior to my owning same, now have approx 3k miles up and all still ok, (now wheres that piece of wood?)
 
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