I hope some well informed person can help identify six mystery brass components that are tapped into the top of this 4.2 cylinder head. They appear to have been cut off/crimped at some point. Does anyone have any idea what these are for and whether they can be removed? Here's a close up shot of two of them (between the spark plug and the the cylinder head domed nut). The engine is US specification with twin Strombergs from 1968. The car has been sitting for 10 years and all history has been lost.

 

OK, I'll bite and take a stab at it. If there are six of these mystery fittings, that means one per cylinder. I'd guess that at least the head, if not the whole engine, is from a later car that had a smog system ( XJ6 ?), and when this engine or head was installed in the E-type the smog system was removed. The fact that the tubes are cut off and crimped, would indicate that in fact they can be removed, and the holes plugged. If this car has been sitting for at least 10 years, the issue will become clearer when the head is removed for inspection.
If this is a car that you are considering buying, check if the engine is original to the car. It may not be. Good luck and let us know what you find out.
Bill.

 

Hello Bill,

Thanks for your very swift response. Yes, there are six of these brass fittings. The engine number stamped on the head is D0397 (as far as I can make out). This does not seem to tally with the engine number on the body plate, however, I don't have the number from the block.

The number on the head would appear to be from a 3.4L Mark VII - could that be correct? Would that fit the 4.2L block? If so, the mystery deepens.
Curtis.

 

Curtis,
I really don't know if the number stamped on the head indicates it is from a Mark VII, or if the Mark VIIs had these fittings on the head. If it is a Mark VII head, it could very well fit on an E-Type block. The compression and valve sizes may not be correct unless some head work has been done.
I guess the next thing to find out would be the engine number, and if the engine number is correct or at least a correct E-Type block, you can always find a correct head or go for an xj6 head with bigger valves.
Bill.

 

Definitely air injection tubes for emission control. The head is probably from the 70s or 80s as I don't think Jaguar was using air injection in the 60s....but I could be wrong on that.

Cheers
DD

 

The tubes are for air injection into the exhaust port to control engine emissions. The head is most likely form a USA XJ6. Back in the late 60's (about 1968/69) cars started to have air pumps added for emission controls. Series 2 XKE's never had an air pump that I know of. I don't know when the XJ6 started using an air pump.

As far as the later XJ6 head fitting a earlier block, about 1969/70 jaguar added 2 additional coolant passages to the back of the block & head. Later heads can be fitted to earlier 4.2, 3.8 or 3.4 blocks by plugging the rear set of coolant passages and milling the plugs flat with the head.

I hope this helps.

 

Bob-S, Daytona & Doug,

Many thanks for the replies - at least I now know what they are. I agree that it must be a later head - and relieved that this is a factory modification.

all the best,
Curtis.

 

The ribbed cam covers look like later model XJ6 parts also. I doubt that Mark VII parts would be fitted to an E Type. If it was an XK 120 then yes. Do you suppose that the entire engine in your car is from a later car? You could probably just remove those fittings and plug them with an appropriate length bolt.