Top end engine rebuild w/ pics and video
 

Hello fellow forum members!

Not too long ago I purchased a discovery II with engine troubles. I am going to document the process of diagnosis and repair to help anyone else who might face this issue. I'm using the rave manual to help out with the process but have found this forum to be an excellent source of workarounds not always provided by the rave. I am not 100% sure yet if the problem is only in the top end and am hoping that one of the liners have not slipped. I assume that once I have the heads off I will be able to determine whether the bottom end needs a rebuild which may lead to an engine replacement.

Here is a video of the sound and symptoms

Step #1
 

Looks like I have SAI, not sure if this is a good or bad thing yet..?

Starting out with the left gasket.. Rave steps below

Gasket - cylinder head -LH

Remove inlet manifold gasket

Ok, so far I have removed the viscous fan (a tool is needed to remove the fan or else you will be spending quite some time), radiator, oil cooler and intake manifold. The rave manual suggests that you only remove the intake manifold to start but I plan to replace the cooling system.

Next step is to remove the ht leads from the spark plugs..?

Pic attached

Disconnect ht leads from spark plugs
 

Disconnect ht leads from spark plugs

HT Leads were trivial, but just in case anyone is having an issue removing them I used a set of pliers to simply pull them out. I am now attempting to remove the secondary air injection and have successfully removed one of the union nuts. The nut closest the cabin is giving me some trouble so I have taken the advise of a fellow forum member and purcahsed a set of crows feet wrenches. Still I am having trouble removing the union nut. Any advice would be greatly appreciated! Thanks!

Video

I don't have SAI, so I don't know if removing that nut is an accessibility problem, or if the nut is seemingly seized. If it is the later, my latest go to nut buster is Sea Foam Deep Creep. Previously, I had been a fan of PB Blaster. Then I discovered the wonders of the Deep Creep. I helps break down rust and galvanization, dissolves carbon, and lubricates the threads. Recently helped a friend change spark plugs in his 5.4L Triton Ford. Professional mechanics hate these engines because the plugs carbon up and break on removal necessitating a lengthy process for removing the broken plug. With the help of Deep Creep, all 8 plugs came out easily, as the carbon was liquefied.

I thought Deep Creep was an adult film star but from based on your description it sounds like I need to pick some up.

HAHA, going to pick up a can of that stuff. So what size is the union nut, 22mm? I've been trying to use a set of pliers with no luck and need a better tool to get to it at an angle.

if it's the one perpendicular to the head, it's a 27mm. You can get a 27mm combo wrench at Home Depot for a few bucks.

SAI Union nut removal
 

Success!! Due to the difficulty of this step I will take more video in a few. The required tools for this step are an 18mm crows foot wrench, short ratchet extension, and 27mm combination wrench. And you were rite about that sucker being at home depot for 8 bucks, thanks!

I believe the next step is to remove the valve cover

what is your ultimate goal here to replace the heads gasket?