Unusual items on 4.2 engine rebuild

I recently accquired a S2 XJ 4.2 motor to replace my oil burner

later, I found out this engine had a big dollar rebuild

there is something unusual they have done, that I havent seen before

see 2 pics…those round silver items are ~1/2" diameter, and say “guarantee void if removed”
(if you zoom right in)

there is 2 drilled in the back of the head (pic), one in the upper valley, 2 in the exhaust welch plugs,(pic)
and 1 in the intake welch

the outer grey ring has silicone-like consistency

presumably these are “heat plugs” inserted by the rebuilder for warranty purpose?

it seems strange to me to setup potential extra failure points, especially at the rear of the head

The receipts show JagDaim (Australia) to be the rebuilder, (they claim to be Oz largest supplier of Jag parts)

Interesting, I had heat sensors fitted to my fore and aft core plugs, but they were stick on, and registered the max temp attained…I think I would be tempted to plug those in the back of the head, but dialogue with the rebuilder should enlighten you…

I would assume they are sacrificial anodes.

Mike Eck
New Jersey, USA
www.jaguarclock.com
'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2

http://www.engineheattabs.com/products

stick ons…that makes sense!

got the receipts emailed to me for this rebuild, which included new stepped sleeves bored 30thou over, 9:1 pistons, crank sludge plugs done, new everything, manual choke conversion, dynoed, little touches of class like copper washers everywhere backed by bellville washers etc etc…the ebay seller got a bit cranky when he found out, but I was the only bidder at $300, as his description was “XJ motor, was working when removed”

I saw Mike’s “Sacrificial Anode”, and thought, “ok, fair enough”, but I kept wondering what kind of madman would drill a hole through a core plug, either before, or after installation. So I googled about a bit.

my bad for being dumb enough to use the word “drill”

the grey stuff looks like solder, it wasnt till I touched it yesterday that I felt it was rubbery