12A185 Head Question

[Gary Schulz]

I have a lead on a good 12A185 Cooper S head as a replacement for my AEG163 head. Is this a viable alternative? Is it equally prone to cracking as the 163?

My search for a decent 163 head seems to have come up empty with several dead-end leads so would this be a comparable alternative?

[bwaminispeed]

Both the 185 heads I have, are for small bore engines, one is open chamber, like a 12G295, the other is closed chamber, like a standard 998 head, but, with slightly larger intakes very much like a 202 head......

The 185 heads were mostly used on 1098 Midget heads, and, a few went on 1100 saloons, between the 202 heads and, the 295s...

Although, I have heard that some early S's had 185 heads, unless there was a third edition of that head, with the chambers spaced for the large bore blocks, I have trouble believing that......

Would the factory really put small bore spaced heads on big bore blocks??????????

[Gary Schulz]

I am told this is an original early Cooper S head (1071 I believe) using 11 studs. It is apparently for the bigger bore engines. It has very large valves that look just like what I have on my 163 head. Pretty much zero space between the intake and exhaust valves.

[bwaminispeed]

OK, looks like they made 3 different head castings with 12A185 casting numbers.........

Closed chamber small bore, open chamber small bore, and, open chamber large bore.....

Whacky.........

Both my small bore 185 heads have the wider space between the two middle cylinders typical of small bore heads......

Nice to now know the answer to the 185 mystery.......

[251 ENG]

Early 1071,s used a head with 12A 185 cast on it but it was more like an AEG 163 than the 997 cooper head .

It was replaced by the AEG 163 .

They are incredibly rare and normally completely knackered

[mk1]

I have an almost mint 185 S head. As Simon says it is similar to the 163 but there are some very noticeable differences.

The inlet ports are more restricted than in a 163 with a flat plinth directly behind the Inlet valve making the inlet tract a bit convoluted. These are also FAR MORE Prone to cracking & general disintegration than the slightly later 163. This is regularly referred to in old tuning books. The 185 was often referred to as "The Yellow Head", where as the later 163 was "The Blue Head". In period the Blue was always considered a far superior head to the early "Yellow".

IF your car is a very early 1071 that should have been fitted with a 185 then it is certainly worth considering, but if your car should have been fitted with a 163 S head then why would fitting a 185 be any less incorrect than fitting a good 940 head that doesn't have all the weaknesses of the early heads & is "no less wrong".

[Gary Schulz]

Mark,

Good to know. I am only considering it because it has become available to me and I can't seem to find a 163 head since all my leads have gone cold.

If I could get a viable 163 head I would use it instead since that was original to my mid '64 build 1275 S.

[steve1071]

Does anyone know the change over point from the 185 to 163?

[mk1]

The 163 head was well down the development road as early as March 1963 as proven by the following letter. I don't believe the 185 was fitted to anything after July / Aug 1963.

http://mk1-performance-conversions.co.u ... letter.jpg