Hey guys,

I had a blown head gasket so I took apart my 98 4.6 Expedition. I marked everything and took pics before proceeding to remove anyghing. Problem is, when I looked at my camshafts they weren't 90° to my cylinder heads when I took apart the timing cover even though the Crankshaft pulley time mark was dead on 12 o'clock. Anyways, driver side was accurate but the passenger side was off by about 3-5 links facing in-ward. So instead of facing outward at 90° it was facing pretty much straight up to the sky.

Alright, keeping this in mind I marked everything and put it all back together just as it was. Truck started right up but there was a clear knocking sound coming from drivers side in 2-3 second intervals.

So I took it apart again only to see that the chain isn't where I left it. So I bought new timing tensioners and guides since the sprockets and chains looked absolutely fine. Problem is, I have no idea how I should time her now that she was off when I took her apart. Should I just line up the Crankshaft to 12 o'clock, take off the camshafts, place them exactly at 90° to the cylinder heads facing outwards and make sure the marks I made at the ends on the chains sit right on the timing marks on the cams and sprockets? Or can I just rotate the cams (while the chains are off) to 90° then set the chains?

Need some help here guys. I've checked out a lot of timing forums but can't seem to find out what to do when the chains are already off.


Thanks guys.

Mo

 

Here is a thread on the subject. Also, the third post down (mine) there is a PDF with the entire timing chain installation procedure.
https://www.ford-trucks.com/forums/1...tallation.html

 

Perfect! Thanks so much for the help! Only question I have now is that since I dont own (or can I afford to buy/rent) any timing tools how can I exactly rotate the Camshafts with the chains off to line them up then hold them in place to put the chain on???

 

Geez you want everything. To rotate the cams put the sprockets on and turn them by hand. In place of a holding tool grab yourself a helper than can hold the sprocket in place for you.

 

I figured as much but I wanted to make sure. Kept reading horror stories about rotating the cams manually that caused severe valve and/or piston damage. Thanks again! I'll let you know how it goes.

 

Well yes that will happen if you rotate them around. I was suggesting minor back and forth movements to get everything lined up. If you have to do any full rotations then you have to loosen the valve hold downs to allow the valve to rise up and clear the pistons. Naturally if you have to end up doing this, line up the rough timing before bolting the valves back down.

 

Figured I'd post an update.

So I finished lining everything up and manually rotated the crankshaft a full powercycle and the chains just wouldnt hold tension so I took everything apart only to find that I needed new tensioners.

While messing with that I noticed that rocker arm #6 on the passenger side (for exhaust valve on cylinder #3) wouldnt sit on the valve straight. So I took off the head and detached the valve spring and noticed a part of the valve guide on the actual head chipped off. So I sent the head to the shop to get a new guide installed and ordered a new exhaust valve, spring, stem guide and seals. Dude at the shop said no more damage was done.

Only reason I can think of for the damage was the piston knocking against the valves when the timing was off because when I was rotating the cams (manually) I was careful to unbolt them to ease pressure on the valves before rotating them too much.

Anyways, the head should be ready tomorrow so I can get back to work.

 

Oh man, this sure turned out to be more involved than what you were hoping for.

 

Took a few days of putting in 4-6 hours of work a day but she's purring like a kitten now. No leaks, no knocking, no weird noises. Will post video of first start when I get a chance. Thanks for the help bro!!

 

Now you know why shops charge so much!

 

Alright, so she ran perfectly for a few days, then she overheated again. Only to about 2/3 of the way (and only for a few seconds) but still. When I got home it took forever for the pressure in the reservoire to clear up so I could check it. Water was low so I put about a gallon in it to fill her up. Then I started her up with he cap off and she spit out all the water in her, almost immediately.

She was doing the same thing before I replaced the head gaskets and a dealer and an independant mechanic both told me she had a cracked head gasket. When I tool the gaskets off both were fine but the heads were warped in some areas to .007 so I figured that was it, I had them both resurfaced.

Before I did the head job I replaced the water pump, radiator and both hoses, and thermostat. The front heater core is bad so I bypassed it.

I cant think of anything else at this point. She's riding with no thermostat right now btw. Any ideas?