I am new to Jags but not new to cars. I just bought a beautiful 1986 XJS V-12 Jaguar with a dropped intake valve seat on the number 12 cylinder. The car is from southern California and is just gorgeous aside from the threads letting go an the front seats in a few places. The head is pulled and the cylinder is undamaged as well as the piston. My question is: where can I get another valve seat and should I be concerned about the other valve seats getting loose? I intend to do a complete flushing of the coolant system and replace the thermostats to be on the safe side. I am also going to pull the other head and do a valve job on both of the heads. Thanks, Gary.

Submitted by silver007@shaw.ca on Mon, 05/17/2010 - 11:21

I would do what I did, send the head to a HEAD SPECIALIST and have the seat fixed....I would not have them plane the head unless you have major warping. in that case I would buy a rebuilt head..... hopefully they would have re line bored the cam bearings. Coventry West is a reputable co for rebuilt parts......

Submitted by bonnettoboot@e… on Mon, 05/17/2010 - 10:07

Be aware Gary, a loose seat invariably means serious overheating, this almost always happens on B bank due to; a faulty thermostat or a non-op electric fan. most times the head and the sandwich plate below it are warped and that is a big problem. If you do go ahead I would advise you to leave the other head alone apart from checking valve clearances and new gaskets.

Submitted by SE98-32482CJ on Mon, 05/17/2010 - 07:51

Gary pull both heads and have them checked by a machine shop or send them to a well versed rebuilder (contact me off list for recomendation). The seat dropped because it was overheated and so the damage may or may not be limited to what you call #12 (Jaguar refers to the cylinders as 1-6A and 1-6B which will help you in the future. Do you have manuals? If not consider our Shoppe as our prices are great for members. So your choice to pull both heads and flush are correct and proper. The valve seat by the way is part number EAC3639 (intake) and EAC3641 (exhaust).