Head Replacement

I apologize in advance if there is already a thread on this, I searched, looked through the entire How To section, and haven't found quite what I'm looking for. (Though I find it hard to believe that there isn't a large number of people that have experience in this field)

So, after some time I have diagnosed various issues with my explorer and it is time for a head replacement. I was hoping to wait longer and upgrade heads, new cam, new lifters and rocker arms. But this needs to get done so I'm going with stock heads on my '93 and just getting her up and running.

Before I start this project this coming weekend I figured I would see if anyone had a few helpful tips here or there for anything unexpected they encountered or small things I may have looked over. My plan is really just to get in there and replace the heads with complete, new heads. I have all gaskets and heads waiting. Plan to soak the exhaust manifold bolts in a hefty amount of pbblaster.

So, any hints, tips, or tricks are welcome and very appreciated.

PS: Anybody got the torque specs for the heads? And I thought I read somewhere there was a certain tightening order as well...

Installation


NOTE: The 4.0L engine should always be assembled using new cylinder head bolts.

1. Position cylinder head gasket(s) on cylinder block. Install cylinder head locating dowels. Position the cylinder head(s) onto the gaskets and locating dowels.
NOTE: The cylinder head(s) and intake manifold are torqued alternately and in sequence to make sure of correct fit and gasket crush.

2. Install and tighten cylinder head bolts, in the sequence shown to 60 Nm (44 ft-lb).




3. Apply Silicone Rubber D6AZ-19562-BA (ESE-M4G195-A) or equivalent to the block and cylinder head mating surfaces at the four corners shown. Install the intake manifold gasket and again apply sealer to the four corner locations.
NOTE: Once applied, the silicone sealer will set up in approximately 15 minutes. The intake manifold must be installed immediately after the sealer is applied.






4. Position the intake manifold on the two guide studs and install the nuts and bolts hand-tight. Tighten the intake manifold bolts in sequence to 4-8 Nm (3-6 ft-lb).




5. Tighten the cylinder head bolts in sequence to 80 Nm (59 ft-lb).

6. Tighten the intake manifold to 8-15 Nm (6-11 ft-lb).

7. Rotate the cylinder head bolts 80 to 85 degrees tighter in sequence for the final cylinder head torque step.

8. Finish tightening the intake manifold in sequence to 15-21 Nm (11-15 ft-lb) and then to 21-25 Nm (15-18 ft-lb).

9. Install valve push rods. Install rocker arm assemblies as outlined in this section.

10. Apply Silicone Rubber D6AZ-19562-BA (ESE-M4G195-A) or equivalent to the four locations at the joint where the intake manifold and the cylinder heads meet (as shown).

11. Install rocker arm covers as outlined in this section.

12. Install the upper intake manifold and tighten the nuts to 20-25 Nm (15-18 ft-lb).

13. Install the exhaust inlet pipe and exhaust manifold(s).

14. Install the spark plugs.

15. Install the ignition control module and bracket assembly.

16. Install the alternator.

17. Install the accessory drive belt(s).

18. Install the power steering pump to the cylinder head.

19. Install the air conditioning compressor (if equipped).

20. Fill and bleed the cooling system as detailed in Section 03-03.

21. Connect the battery ground cable at the battery.


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hope that helps out! the removal is pretty straight forward. just make sure you follow the tightening sequence exactly....there are like 4 sealing surfaces that all have to clamp down together or it WILL leak. also it helps to put a little silicone sealant in the corners where the intake block and heads all meet....there are 4 corners that will need silicon(see step 10)...youll see what i mean when you go back together. good luck! hope youre ready for a work out...those head bolts are TIGHT!

Thanks for that. I'm more than positive it will save plenty of aggrevation and time . Disassembly begins today, time to see how good/bad things are in there. Anyone feel free to chime in any time, every bit helps.

Bag and tag all your bolts. Make sure to record how every little bracket, clip or loom holds whatever it holds; otherwise you'll have all sorts of lines and cables crisscrossing it'll look like a squid fight. and one other thing TAG ALL YOUR ELECTRICAL CONNECTIONS

dont forget to replace things like plugs, wires, thermostat, air filter, fuel filter, and all those cheap tune up parts...youre going to be in there anyway...might as well get it done now. and when you fill it back up with coolant make sure to get all the air out. and please please please dont cheap out on the plugs...buy motorcraft...they arent even expensive...ive seen so many driveability issues caused buy bosch, autolite, and other cheap plugs.

o and check your cats! if you had coolant running through the exaust there is a chance it could have plugged your cats...just something to check....dont get too worried about it.

Thanks for all the info. I took it easy today and got the valve covers and intake manifold completely off. Tomorrow morning starts with the removing of rocker arm shafts and heads. Switch a few parts over to the new heads, and back together we go (which I plan to do hopefully by the end of the night if all goes well). Trying to keep things a liesurely pace so as not to get too frustrated Thanks again guys.

So far so good on day too of laid back head replacement. Only a few hiccups today such as rounding off the head of a bolt or two... and the rounding out of one of the torx head bolts (good thing the new ones were going in anyway), and broke a lifter cup pulling a head out (that was a 50 dollar fix from a semi-local napa). Found as expected and then some. Rear passenger side cylinder: incomplete combustion due to what appears to be coolant leaking in. The surprise, found the same thing on forward most driver side cylinder as well :thumbdwn:, leading me to believe whole heartedly what others have put forward: that there is a weak spot in the cylinder head design. Other than that great combustion in the other 4 cylinders and the cross-hatching was still visible after 128xxx. Lifters, rocker arms, and pushrods all seemed in good shape, a little shiny on pushrods and rocker arms, but no actual indentation.

Anyway, got the new heads in. Decided to take care of the nasty valve covers and painted them a nice metallic ford blue with engine enamel and then went with a metal flake grey/silver under a clear coat for the upper intake manifold (we'll see how long that beauty lasts).

Tomorrow is the big day, fill up the radiator (hopefully avoiding air pockets, any and all tips on that are encouraged, don't want to overheat the brand new heads), few quarts of oil and see what happens.

Thanks again for all the previous help (the diagrams were an awesome help) and thanks ahead of time for any incoming help between now and tomorrow.

Well for those reading, it all went well. Patched the rest of the little things all up yesterday morning and she fired up great. The temp stays right where it should, it doesn't miss at first start up, and runs/sounds 10 times smoother. Just goes to show you can't rule out the least preferred cause of problems I suppose.

I do have a final question though. I'm sure there is some unwelcome debris in the engine like dirt, small chunks of old gasket, brake cleaner, etc. from the time in between taking the various parts off and plugging the holes they opened. How many miles would you folks run the engine on the new oil I just put in (along with a quart of rislone) after piecing it all back together, before changing to another round of new oil and filter? And maybe another quart of rislone for a full 3000 mile cycle?

jtb would you describe this as some what easy. im a bit short on tools. but i probably need to do this aswell. i only have sockets, screw drivers and some pliers. no work shop either

jtb1689 said:

Well for those reading, it all went well. Patched the rest of the little things all up yesterday morning and she fired up great. The temp stays right where it should, it doesn't miss at first start up, and runs/sounds 10 times smoother. Just goes to show you can't rule out the least preferred cause of problems I suppose.

I do have a final question though. I'm sure there is some unwelcome debris in the engine like dirt, small chunks of old gasket, brake cleaner, etc. from the time in between taking the various parts off and plugging the holes they opened. How many miles would you folks run the engine on the new oil I just put in (along with a quart of rislone) after piecing it all back together, before changing to another round of new oil and filter? And maybe another quart of rislone for a full 3000 mile cycle?

Click to expand...

Just had motor rebuilt, which is a lot more "involved" than replacing a head, but they told me 500 miles... I'd probably go ahead and change oil after 1,000 miles just to be safe in your case. Not expensive to change oil/filter... couldn't hurt

YB - With only sockets, screwdrivers, and pliers you may be in over your head trying to replace the heads. Don't get me wrong you could probably do it if you really wanted to, I personally wouldn't have done it if I were in your situation. Maybe find someone with a wider array of tools such as air tools, torque wrench(which you MUST have), and many others that you don't necessarily need, but help. Oh and a place to leave your explorer for a day or two or three helps.

Mirge - I changed it I think about 500 miles afterwards, and have since changed it twice more as it was a while ago. Thanks for the input though, I'm sure it will help someone later on down the road.

jtb1689 said:

YB - With only sockets, screwdrivers, and pliers you may be in over your head trying to replace the heads. Don't get me wrong you could probably do it if you really wanted to, I personally wouldn't have done it if I were in your situation. Maybe find someone with a wider array of tools such as air tools, torque wrench(which you MUST have), and many others that you don't necessarily need, but help. Oh and a place to leave your explorer for a day or two or three helps.

Mirge - I changed it I think about 500 miles afterwards, and have since changed it twice more as it was a while ago. Thanks for the input though, I'm sure it will help someone later on down the road.

Click to expand...

I guess I need to start checking dates

any how ive decided im going to do this in the near future. i found sludge under my oil cap so i guess its time to do the do. ill post updates later

From my local mechanic he said to change it every 1500 miles to get all the "poop" out of there.