Getting prepared to do an engine and timing chains on a 4.0L | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Getting prepared to do an engine and timing chains on a 4.0L


Active Member
October 23, 2014
Reaction score
City, State
NW. Wa
Year, Model & Trim Level
2002 Explorer
Helping the inlaws by fixing their 2002 explorer, it threw a rod on the highway a couple weeks ago, he bought another engine with 90K on it, and we figured doing the timing chains would be smart.

Ive been searching, and I see everyone says to buy ford parts over cheap ones, we are on a budget, so Im open to suggestions as to exactly what and where to buy parts...

Also the cam service tool kit, is that a must?

Do I need to buy a FSM? or is there a link to enough info on the net?

Appreciate the help


Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

timing chain info

SOHC V6 Timing Chain Related PNs

SOHC V6 Timing Chain Parts Sources

The OTC 6488 timing tool kit will simplify the process and improve the accuracy of timing the camshafts. There are alternatives but using them takes more time and ingenuity.

The Ford Service Manual will provide vehicle specific engine removal/installation procedures. The following threads may be helpful:
SOHC V6 Timing Chain Inspection & Repair
SOHC V6 Camshaft Timing
Balance Shaft Timing Procedure
SOHC V6 Timing Chain Parts Removal Procedure
SOHC V6 Rear Cassette Replacement
SOHC V6 Block Cradle removal/installation

how long to last?

How much longer do your inlaws plan to keep their 2002? From what I've read on the forum the 2002 automatic transmission is one of highest failing transmissions. How many miles are on the odometer?

The Cloyes kit is a good compromise between price and quality. If they only plan to keep their Explorer for another two years you may want to go with the 4USA kit.

If you go with the Ford parts you don't need to purchase all of the items listed in the post. You'll need the left and right cassettes (includes guide assembly, sprockets and chains) and left and right hydraulic/spring tensioners. Also the jackshaft rear plug. If the rear guide upper positioning post is worn you'll need a new one. You probably should replace the primary chain tensioner even though the 2002 had the improved one. The primary chain guide lasts a long time but is fairly inexpensive.

Does the replacement engine have a balance shaft? If so, then you should replace the balance shaft chain tensioner and guide. Replacing the balance shaft chain tensioner requires removal of the block cradle.

You'll need the timing tool kit (OTC 6488). You may want to try to buy a used one on eBay. You need to become very familiar with the engine configuration, how to use the tool kit, and the procedure for timing the camshafts before you start the process. If you post a parts list for your project I'll be glad to review it.

Ill ask him again, but he said after this, there is no reason to get rid of the rig, his daughter is driving it for a DD.

Ill make a list of what I think I need, and I appreciate your double checking!

ok, so, different kits separated by the dashes, part numbers I need to order in bold:

This kit, included everything below it?
Jackshaft/primary timing chain kit 2U3Z6D256CA includes:
Crankshaft bolt harmonic balancer E7RY6A340B
Tensioner-engine jackshaft chain YL2Z6L266AA
Gasket-cylinder/timing front cover F77Z6020AB superseded by 1L2Z6020AA
Sprocket/gear-engine jackshaft/intermediate 2U3Z6M264AA
Guide-engine jackshaft chain 2L2Z6K297AA
Bolt-jackshaft sprocket bolt F77Z6M264BA superseded by 2L2Z6279AA (included when 2U3Z6M264AA is purchased)
Sprocket/gear-crankshaft two wheel drive 2L2Z6306BA
Chain-engine jackshaft F77Z6268AB
Bolt-camshaft sprocket right hand
Bolt-camshaft sprocket left hand F77Z6279BA


Left/front timing chain cassette assembly 7U3Z6A257A includes:
Timing chain
Guide assembly YL2Z6M273AA superseded by 7U3Z6A257A
Bolt-guide assembly upper mount
Sprocket/gear-jackshaft front


Right/rear timing chain cassette assembly 4L2Z6M290AA includes:
Timing chain
Guide assembly
Sprocket/gear-jackshaft rear


00M12 intake manifold kit YL2Z9E473AA includes:
Lower intake manifold gasket set of six YL2Z9461AA
Upper intake manifold gasket set of two YL2Z9E436AA
Left timing chain tensioner 7U3Z6K254B
Tensioner metal O ring XU2Z6M252AA
Oil restrictor
Galley plug


Right timing chain tensioner 7U3Z6K254A supersedes XU3Z6K254BA

Right timing chain guide assembly upper postioning bolt F77Z6U000BA

Jackshaft rear sprocket retaining bolt W703167S430

Cover assy/rear of block jackshaft opening plug F77Z6026AB

Left cassette assembly lower mounting bolt W500100S300

Jackshaft chain guide mounting bolt W500100S300

Sprocket/gear-crankshaft inner four wheel drive F77Z6306BE

Sprocket/gear - crankshaft outer four wheel drive 2L2Z6306AA

Balance shaft chain guide F77Z6K297BC

Balance shaft chain tensioner 1L2Z6L266AA

Balance shaft chain F77Z6268BC

Seal-front timing cover E6TZ6700A was superseded by 5H2Z6700AA

Gasket-lower oil pan 4L2Z6710AA year 2000+

Gasket-upper oil pan/reinforcement section F77Z6710AA

Block cradle retaining bolt seal F77Z-6734-AB (Listed as engine oil drain plug gasket)

Exhaust manifold outlet bolts (M12-1.75X54.5 H) N811747S2 ?needed??

Gasket-valve cover F77Z6584AE (right 01-03)
Gasket-valve cover F77Z6584BA (left 01-03)
other parts

Seal-rear main crankshaft F5TZ6701A or FEL-PRO BS40619 (seal w/repair sleeve) ?needed??

Is that too much? Missing anything?

Still looking for the 6488 tool kit used or to rent also

I'm surprised his daughter is still driving it if it actually threw a rod. It may just have a broken guide assembly. That can make a terrible sound like marbles rattling around in the engine.

she was going down the freeway and it went BANG, but was still running... she pulled to side of road, shut if off, and it was leaking oil pretty bad, they had it towed to their house, where he seen the hole behind the starter in the side of the block. :eek:

Cant wait to see what the inside of this thing looks like!

confirm balance shaft engine

What year and model of vehicle is the replacement engine out of? Did the vehicle have 4WD? Even if 4WD, is there a possibility the engine was replaced with one not having a balance shaft? Before I review and edit your parts list, please confirm that the purchased replacement engine has a balance shaft. Are the block part numbers identical? If not, it would probably be best to wait until the replacement engine is partially disassembled before ordering the parts.

Are you experienced in working on engines? The SOHC V6 is a rather complicated engine to work on.

he said it came out of a 2002 explorer also, Ill find the numbers on it today and verify, should have time saturday to tear it down some and see whats in there.

Been working on engines for over 20 years. Just not a 4.0L explorer motor before.

piston 1 at TDC on compression stroke

Before taking the engine apart I strongly suggest that you set piston 1 at TDC on the compression stroke. It's an interference engine so you can't arbitrarily rotate the crankshaft when valves are extended.

If you PM me your email address I'll send you a copy of the engine assembly instructions that illustrate use of the timing tools and where to place sealant when reinstalling the block cradle.

by apart, I mean taking off covers so I can see whats in there. Dont want to tear it down until I have parts, and the tool kit, ideally.

Tasca Parts

I purchase my OEM parts from because my local Ford dealer requires payment prior to ordering anything not in stock and charges list price. The dealer rarely has what I need in stock so I end up having to make two trips to get what I need. Tasca has a large inventory and sells at a discount price. When I purchase from them my parts come directly to my home and the discount is usually greater than the shipping cost. They are also knowledgeable and helpful when there are questions about which part to order. I used to also purchase online from Tousley Ford at the same discount but they have changed ownership and no longer sell online parts except for local pickup.

2002 minimum parts list

The primary chain kit is normally not needed. The sprockets and chains will typically last for 500K miles. The 00M12 kit components would have already been incorporated in the 2002 engine. The left and right camshaft sprocket retaining bolts are not TTY and can be reused. Primary and balance shaft chain tensioner mounting bolts can be reused. I reused my lower oil pan gasket and the valve cover gaskets. I also reused the block cradle retaining bolt seals. If you leave the water pump attached to the timing cover it saves some time and a water pump gasket. I did not pull the crankshaft front seal and carefully reinstalled the block cradle and cover in the original positions and had no leaks. Many forum members have experienced leaking rear main seals after replacing them because they don't have the special installation tool. If there is no sign of it leaking I would not replace it. If you do replace it, don't use the repair sleeve unless the crankshaft has been scratched.

Here's a minimum list of parts for the 2002 assuming it has a balance shaft. Hopefully, I haven't forgotten anything.

TTY bolts that can't be reused:
Harmonic balancer retaining bolt. The harmonic balancer was changed for the 3rd generation so call Ford for correct part number.
The jackshaft front & rear sprocket retaining bolts aren't specified as TTY but are torqued as if they are.
Front 2L2Z6279AA
Rear W703167S430

Cover assy/rear of block jackshaft opening plug F77Z6026AB
Right/rear timing chain cassette assembly 4L2Z6M290AA
Left/front timing chain cassette assembly 7U3Z6A257A
Left timing chain spring/hydraulic tensioner 7U3Z6K254B
Tensioner metal O ring XU2Z6M252AA (optional)
Right timing chain tensioner 7U3Z6K254A
Tensioner metal O ring XU2Z6M252AA (optional)
Tensioner-engine jackshaft chain YL2Z6L266AA
Guide-engine jackshaft chain 2L2Z6K297AA
Gasket-cylinder/timing front cover 1L2Z6020AA
Gasket-upper oil pan/reinforcement section F77Z6710AA
Balance shaft chain tensioner 1L2Z6L266AA
Balance shaft chain guide F77Z6K297BC
Gaskets-intake manifold 3rd gen
Gaskets-exhaust manifold 3rd gen

If the right guide assembly is broken then you'll need the upper positioning bolt F77Z6U000BA

took the valvecovers off last night, pass rear was already failed, good thing we decided to do this!






normal plugs?


clean engine

The engine looks pretty clean with very little (if any) sludge.
Try to find all of the pieces of the failed cassette guide. I actually reassembled the pieces to determine if any were missing. Some were in the oil pickup tube screen. Another was in a pocket in the head near the lower mounting bolt casting.

The last piece was behind the jackshaft rear sprocket.

It looks like the guide upper positioning bolt is worn from being struck by the loose chain.
It may just be the photo but the spark plug gap may be excessive.

Be aware that at some year (2004?) during the 3rd generation the head or block casting was changed making it very difficult to remove/install the left cassette guide with the head installed. There isn't clearance for the guide pivot bushing.

The latest guides have pivot bushing with a circlip instead of a pressed pivot bushing to allow disassembly.

Please post your block part number and if you have problems extracting the left guide assembly.

By the way, for the SOHC V6 the last 8 digits of the VIN are stamped on the rear of the block on the driver's side as shown in the photo below.

The tenth digit of the 17 digit VIN indicates the year of manufacture. The identifier changed in 2001 [1998(W), 1999(X), 2000(Y)------2001(1), 2002(2), 2003(3)]

Ill get that vin number, and pull the pan today, gotta grab a couple bolts to get the dampener off.

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!



Missing something here...




Seal possibly been leaking a little?

No clue where the parts from that first one are, and the pass rear must all come out the top, cant get to it from the bottom.