Part of my engine saga was checking the valve tolerance and having to return it to the shop in another state to have it corrected…just got it back today. On removing the head previously I broke the thin area of the head gasket that seals the timing area. I have a new head gasket in my cart to order and before I purchase it was wondering what the pressure really is on the front of this seal anyway. I imagine it isn’t as vital as the surface area around the pistons. I’ve used Permatex The Right Stuff on other gaskets to repair broken areas with success- seems like this is would be an easy place to monitor because I can see it inside with the cam covers off and the outside. Should I order a new seal- is repair a bad idea?
Side note: I have many new old stock head gaskets from 4.2 Jags still sealed but they are probably 25 years old. I collected them with other parts purchases. I imagine head gaskets have rubber/fiber materials that have a shelf life- should I feel bad about tossing them?
Ben the area on the gasket you are speaking of is the area that is mostly likely to leak - oil in this case. I can’t comment on your broken gasket, but if you use it, or a new one be sure to seal both sides with a gasket making compound. This is particularly important around the 6 holes where the 5/16th studs come though. The oil likes to leak down the studs, and will do so if you don’t seal it correctly.
Thank you! Never thought of that- I was considering putting the head gasket on dry but sounds like some copper spray gasket on the primary surface area to ensure a good seal near the pistons and maybe a bit of Permatex Aviation Sealant around the small 5/16" studs.
Ben - If you have a 4.2 and are using a fiber head gasket I would not add any additional gasket material on the portion that seals the piston area. Jaguar decidedly does not recommend it. I’ve never had a fiber gasket leak - I’m sure they do, but if your head and block are properly prepared it’s highly unlikely.
