Dominator cylinder head identification.

Looks like it could be right for a later DD  88SS   as long as the bolt  holes are drilled for the same size as the 88 barrel.  . Will need some welding and new seats . Hope you only paid about £50 !!.

On further inspection I think this could be a 750 head  .  Not suitable , make a good door stop.

Hi Jonathan have one of these heads marked 22707R on a recentley acquired  1959 Dominator 99. 

I have not been able to find any reference to the "R" suffix and don't know what the head was originally fitted to.

It has 28.5mm inlet ports which may rule out the larger capacity twins???

If you get a full explanation you may have solved a mystery for me too.

Keith

I don't  think that it is a 750 head, the spigot recesses appear to be concentric to the combustion chambers, which marks it as a 500 or 650, these were the same p/n if memory serves.

Just about anything is repairable, given enough time, money, equipment and skill, but as to whether or not it is economic is another thing altogether, this is well beyond the scope of the average enthusiast, somebody like SRM could probably do it, but it would be very, very expensive, and finish up costing you much, more than another, serviceable head, if you could find one.

This cylinder head is actually a very early AMC machined 650 (or 88SS) cylinder head.  Probably from late 1963 or soon afterwards. The 23166 number was added to the 22707 casting number to show that this head was a Birmingham casting but machined at Plumstead.  After AMC had finally got their act together, their own castings just had 23166 for the 650 and 750 cylinder heads (different bolt hole positions on the 750 heads).

The later spigotless 650/750 versions of these heads were numbered 25319 and the post 1967 650 / 750 and Commando engines, with slightly longer valves, were stamped with just 06-0380.

The excellent photos show this is not a 750 cylinder head. The bolt holes each side of the plug would be 2.5mm further apart and the combustion chamber widened with a crescent shaped step by the inlet valves. See attachments.

Although repairable, I think the damage would be very costly to fix. Also major cylinder head repairs tend to warp the casting which then leads to gasket sealing problems. There are plenty of good Norton Twin heads available on the market place for far less than the cost of fixing this head.

The suffix letter seen on most 22707 cylinder heads is a foundry identifier to show which casting blocks were used to make a particular head. There are at least 6 of these using letters such as K, L, M, W and others.

I have got one like that in my collection, I paid £6 for it. It needs a new valve seat. I have the equipment and will fix mine one day. Try Steve Maney, he takes most repairs on.