Recently snagged a '98 Disco I off of craigslist for $800. It's 132k miles, and after fixing the minor floorpan rust, it's time to fix the head gasket. It's leaking compression on #4, and chuffs like a steam engine. I've got a big pile of parts to put on, and want to make sure I didn't miss anything in my research.

The Plan:

- Rip off heads, have machine shop clean, pressure test, install new valve seals, grind seats if necessary. Using a Victor-Reinz H/G Kit.
- Install new 4.6L cam, lifters
- Replace oil pump gears, timing chain, cam and crank sprockets, timing cover and oil pan seals. (All OEM Parts)
- High-flow Water pump (GMB) and thermostat
- Flush radiator
- New Plugs/Wires
- Replace all hoses, belts, fluids.
- Switch to Rotella 15w40, and gigantic Hastings LF434 oil filter. Read the oil/filter thread in the tech section sitcky, this filter has a bypass valve set the same as the OE filter, but it's massive. Catalog says it's for industrial air compressors/CAT Diesel Generators.
- Oil press/ Water temp/ volt meter

Did I forget anything?

 

Pretty extensive list.

I would also suggest-

- rodding the radiator.

- new fan clutch

And of course serp belt.

I didn't know you could use a 4.6 cam on a 4.0. Do you know what the gain is? Decisions, decisions.

 

From what I've read, it a bit of an increase in power in the bottom end, but nothing crazy huge. I've read that the "best" in terms of price/performance for the 4.0 is putting in the rotating assembly from a 4.6 (crank, pistons, cam etc.) but I'd rather just get the truck running again instead of pulling the motor. I plan on using this 4.0 until it gives up totally, and a lot of the reading I did talked about excessive cam and timing component wear @100k. I figured I would just do it while it was apart, and if I go to the trouble of pulling the engine, might as well put a refreshed 4.6 back in. Pulling the engine opens a bigger can of worms than I'd like on a truck I've hardly driven yet. We'll see if I can get to 200k on the 4.0 without going nuts, And I can get OEM parts through my work for less than wholesale, a 4.6 cam and lifters is a pretty cheap upgrade.

I'll add the fan clutch to the list as well.

 

From what I have read you only need to swap the crank and rods not the cam, only difference is supposed to be the stroke


that said if you do the cam do a timing se,t front main seal and oil pump while it is apart


may also want to drop the oil pan and check the pickup and clean sludge from the pan

 

That's the plan! I hadn't heard that about the cam, I do know the cam part numbers are different in my catalog.

 

From reading I believe you would also need to get the ecm set to 4.6 iirc both programs are there but a scanner changes it? It will run set to 4.0 with the 4.6 crank and rods just not getting full benifit, I wanted to do this eventually but there is info here on it and on discoweb

 

My first mechanic threw a 4.6 short block in my car with no ECM set change, and the motor ran like a striped Ape! Too bad the short block had some issues and had to be pulled and changed out for a 4.0. He said it was a full plug and play and the times that he has done it he never changed the ECM and the motors run great. He even said, in his opinion, they ran better with the 4.0 ECM. Go figure...

 

So was the mpg better? Also read putting stock ford injectors yeilds more power and better MPG from better fuel atomization

 

I only got to drive it home to turn around and give it back, starting making a ticking noise.

I bought the Ford injectors and have a buddy that installed them. Said his car was peppier off the line and a mild increase in MPG, but nothing that translated to noticeable savings. But, He swears by them. After his testimony I went right out and bought some. Now Im debating on installing now or waiting to build my dream 4.6.

A member on the forum just clued me in on a Shop called Q&E here in SO Cal that will top hat a block for $1500. Im looking to do that and replace the crank, rods and pistons from a Bosch 4.6 I picked up.