Mystery bolt holes on block

Hi. Just bolting bits back on my 4.2L engine out of my '68 E-type. To the right of the oil pump there are 3 bolt holes. I don’t believe these were used for my engine. There is also a central bolt hole that was sealed with another bolt. Is this

a legacy of a previous engine or is it for an option that I don’t have? Cheers, Lloyd

What is the serial number stamped on your engine? It is located on the flat area just below the “Jaguar” cast into the side of the block.


Hi Paul. I’m guessing that given there’s a mirror image of the 3-stud pattern on the other side of the block, that it’s for mounts for a different Jaguar vehicle. My block is 7E54369-9.

XJ6 Engine mounting points .

Hi Ian, was guessing it was mounting (as mentioned above). Thanks for verifying. And then there’s that middle bolt, which you can see through the middle left side of the bracket. Another variation? Thanks, Lloyd

That bolt goes into the oil gallery , you can hook up a mechanical oil pressure gauge from them .

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According to the Jag-Lovers page on XK engine serial numbers, a 7EXXXXX-9 serial number would be correct for your E-Type.


Hi Ian. That’s handy to know. Thanks.

This is how my XJ6 engine come to me , still has the oil pressure Sensor in place , you can fit one in place of any oil gallery bolt , that run’s along the block !

Thanks. That’s handy to know.

The larger of the two holes that are plugged with slotted screw plugs is where they drilled the oil passage through to the center main bearing, just like the six to the other main bearings that are plugged with brass hex head screws. On some XK engines this hole is left open and just connects to a passage in the filter head, same as the larger hole beside it. On some it is blocked with a core plug, XK150 and late Mark 1 I believe.

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Hi Rob. thanks for the pic and info.

It’s the mounting point of the XJ6 and Daimler Sovereign engine mounting brackets. Only the later 4.2 blocks had these holes machined out making the block universal.