Bolts sticking out of cylinder head?

[katy]

What are these bolts sticking out of the cylinder head for? They are in a 1275 engine out of our '61 MM. There is one beside each spark plug, they are 7/16-20 UNF thread and there is a small hole behind each bolt. I suspect that they are just plugging the holes of an emissions related set up of some sort. Neither the BMC manual or Vizard's book show anything similiar. I don' have the cyl head casting # as some goofball has glued the valve cover down w/silicone and I haven't been able to pry it loose yet.
TIA, Ken[frame][/frame]

[Simon P]

Interesting...
I don't think these will be emision related as they would appear to directly enter the combustion chambers,
I seem to remember reading about a diesel 948cc A series engine that was used in a small nuffield tractor,
Although obviously not the same as your head it did look quite simular as it had heater plugs fitted in the same location's,

Hopefully somebody will be along to shed some light on them

[Simon P]

Just had a quick google and came up with a 12G1316 cylinder head,

Your quite correct with regards to emission's,
Apparently reffered to as the american smog head and is described as an excellent base for heavy modification,

[bmcecosse]

Yes - it's the rare 12G 1316 head, and these are the ports for air injection to 'fiddle' the emissions figures! I have one of these heads 'in stock' - it is 'supposed' to be good for modifying but to be honest it looks just the same as my other 940 heads!

[katy]

Thanks for the insight. I think I'll cut the bolts off, then cut slots in them to screw them back in. Won't be as ugly and obtrusive then.

[bmcecosse]

Blimey! You may have some problems getting them out after all these years - my advice - leave well alone!

[katy]

Well, they came out w/out a problem. The head isn't as rusty as it looks in that pic. Methinks that in the resizing of the pic it lost a lot of quality.