4.0 SOHC Timing Chain Qestions | Ford Explorer Forums - Serious Explorations

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4.0 SOHC Timing Chain Qestions

TonyTiger2004

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Joined
June 27, 2010
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City, State
Manchester, TN
Year, Model & Trim Level
1998 XLT 4.0L SOHC
Hey guys.. been awhile since i posted about my 98 Explorer i Got.

I got a replacement engine from a good Low Mileage Scrap yard... The engine looks like at one time its been gone through... But i got a scare when i started switching some components from my Locked up engine. When i pulled off the Lower Oil Pan i seen quite a few pieces of Plastic Timing Chain guide pieces. So i proceeded to remove the Passenger side Valve cover to have a peak at the Back Timing Chain cassette from what ive heard its the one that you usually have problems with first.

Well it appears to be intact and fine. I am fixing to remove the from timing cover and the other valve cover to see what they look like.. I was thinking possibly its already had the timing chain guides replaced as this engine come out of a Government used Explorer.

So the questions. How do i really know if this has been done? I noticed the Cloyes Timing chain kit (4x4) guides where BLACK but ive noticed quite a few that are white. Does the new guides have the metal Backing on the tensioner side? There is hardly a 1/4 Inch of play on the back timing chain.

Note: Supposedly the ran the engine up to 2500 RPM from a Cold start with 0 Timing Chain Noise. It being a government vehicle you would think it woulda have well over 170K miles of which you would think the guides would have given out and been replaced.


Any Help or Advice would be apreciated. Ive read alot into the timing chain issues on these SOHC Engines. I know it requires or well recommends the use of the Specialty tool kit and the cheapest ive found the Complete Timing Chain Set for 4x4 is $255 Dollars Shipped (CLOYES 9-0398S)
 



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Thanks.. The Kit i was looking at is from 4USA for $151.00 Free Shipping on ebay.

But what are the signs that the timing chain components have been replaced?
 






old parts

Here's a photo of my old rear guide assembly:
RCasset.jpg

There is no metal reinforcement on either the traction or slack side.

Here's a photo of my old primary tensioner:
PrimWorn.jpg

The newer style has a much larger and stronger base. There are six leaves in the spring instead of only three.

I couldn't find a photo of my old front guide assembly. I don't remember if it was all plastic or if there was metal reinforcement on one side.
 






Thank you. So ideally if im checking it out and its got Metal reinforcement it should be good long as its all intact.

But if its all plastic regardless if its broken or not should just go ahead and install the updated timing components since the engine is out right now.
 






repair vs replace

Some might argue that it may be better to simply replace your engine with a later model (and lower mileage) engine from a salvage yard. That way all of the engine components would be more reliable due to less wear. Even if you perform all of the labor yourself the OEM timing chain parts are fairly expensive as is the OTC 6488 timing tool kit. Personally, I think failed timing chain related components represent the most probable expensive engine repair. Since the traction side of the rear guide assembly is still not metal reinforced it could break as early as 50,000 miles although that is unlikely. I chose to repair my engine with new timing chain components rather than chance a salvage engine that could have existing or near future timing chain problems.
 






Thank you Dale, How many miles have you driven on your repaired 4.0 Thus Far?

Also... Ive seen some people saying the Heads must be removed to install the rear and front timing guide assembles. And from what it looked like on yours you never removed the heads. I plan on working on the engine this weekend going to finish diagnosing the timing guides and tensioners to see if they had previously been replaced or still the originals.
 






heads can stay on

Thank you Dale, How many miles have you driven on your repaired 4.0 Thus Far?

Less than 2,000 miles. Being retired I don't drive much and my Sport is my second vehicle.

Also... Ive seen some people saying the Heads must be removed to install the rear and front timing guide assembles. And from what it looked like on yours you never removed the heads. I plan on working on the engine this weekend going to finish diagnosing the timing guides and tensioners to see if they had previously been replaced or still the originals.

It is not necessary to remove the heads to replace any of the timing chain related components. This thread may help you assess your timing chain problems: SOHC V6 Timing Chain Inspection & Repair
 






Thank You!

Thank you dale again. You have been some big help... I plan on tackling some of your mods once its up and running. Been looking at quite a few of your helpful threads.
 






Timing Chains UP Close and Personal



Here is what Ive discovered.. Only question is the best way to determine if it may of jumped time? From the Haynes Manual it says at TDC. The crankshaft Key (Torque Converter Key) will be exactly straight up On Compression Stroke. So i checked that and looked at the valves and they appeared to be closed.

Engine Rotates fine, No hard or start stop action. No teeth on the Sprockets looked rounded off or Broken or what have you. Any input or suggestions will be appreciated. Going to Order the Timing Chain Kit This Week.

If you notice in the video the primary chain guide is still intact and pretty Taught.

Thanks, Tony
 






bad tensioners?

You have the old style primary tensioner and it is obviously shot. Even if it were still functional I would replace it because the later one is superior. The timing rarely slips due to a faulty primary tensioner. There just isn't that much excess length in the chain. The primary chain guide should last 500K miles but it is cheap so I would replace it.

It looks like your balance shaft tensioner is also broken. There should be some tension in the chain to prevent easy deflection. Unfortunately, the block cradle usually must be removed to remove the mounting bolts for the tensioner. Some members have been able to slide part of the old tensioner out and parts of the new tensioner in without removing the mounting base and therefore the cradle.

There is excessive slack in the rear chain. The spring in the hydraulic tensioner or part of the guide assembly may be broken. The upper locating bolt section of the guide appears to be intact. I suspect the lower part of the traction side of the guide assembly is broken near the pivot (lower mounting bolt). You might confirm that by pulling up on the guide assembly at the upper locating bolt section. You can remove the upper locating bolt to see if that allows more movement.

Since the crankshaft rotates two turns for every turn of the camshafts you have to be sure that #1 piston is in compression when the crankshaft is at TDC. Some members put their finger in the spark plug hole and feel for pressure. Another way is to make sure the camshaft lobes for #1 are up instead of down. Also, the camshaft position sensor nub on the left camshaft should be above the axis of the camshaft instead of below. Looking at the crankshaft keyway is not a very accurate way to determine TDC.

If the rear guide assembly is broken you will have to retime the camshafts after replacement. The OTC 6488 tool set simplifies the process and results in more accurate timing. What about the left guide assembly? Have you pulled the left valve cover and inspected? It looks like part of the left guide is laying behind the primary chain between the crankshaft and the jackshaft.
 






Timing

The back guide is still fully intact, Its still connected at the pivot.. I noticed when i rotated the engine that back timing chain got really taught.

The left side is shot also that piece behind the primary tensioner is indeed a piece of the front, this is why i have not removed the other valve cover yet.

And i do believe the Balance shaft guide is shot also, i will have to remove the reinforced section of the oil pan to really examine it. But i will need to remove it to retrieve some timing chain guide parts and some of the spring material that come from the primary.

What i really dont understand is the front timing chain to the left side is not very lose. But you can clearly see a big chunk of the guide has come lose.

I will be replacing the right and left side, as well as the primary and balance shaft. I do not see a point in leaving any of it since the engine is not in the vehicle i would rather get it all done.

But i wonder if the cams will need to be re timed, or just held in place with the tool kit for replacement?

Any advice will be appreciated.

Thanks, Tony
 






left guide assembly

The left guide assembly is fairly straight on the traction side so if that side breaks there is little change in the chain deflection.
LCassette.jpg


The following thread may be helpful for disassembly: SOHC V6 Timing Chain Parts Removal Procedure

It is important to have the crankshaft positioned so #1 piston is at TDC on compression stroke before loosening the jackshaft sprockets or the camshaft sprockets. Then don't rotate the camshafts or the crankshaft until the engine is reassembled and camshaft timing is begun.

Post #5 of the following thread details the camshaft timing procedure: SOHC V6 Camshaft Timing

Camshaft timing is normally done after the front timing cover and harmonic balancer is installed. The procedure is fairly complicated and if not done correctly the engine can be damaged in the first minute of running. I suggest you read the procedure several times before beginning it. Look at photos in the various threads until you fully understand how to use each tool in the tool kit.
 






Timing Procedure?

Ok so you time the jackshaft and Crankshaft with number 1 cylinder at TDC on Compression stroke.. Install all guides and sprockets with it at TDC compression stroke. Then install timing cover and balancer before you time the Cams?

I will probably get a tool kit off of a friend fairly cheap. Will it have the timing procedure or should i use the procedure from the Haynes Manual?

What about the balance shaft chain and guide assemblies how are they timed?

Im going to read the threads you posted on previous post.

EDIT: Do you have the part numbers of any additional parts that are required that is NOT included in the Timing Set like the Sprocket bolts that need to be replaced, and are these parts avaible from local parts house or should they be ordered?

And is this the Kit you bought that u could recommend? ( http://cgi.ebay.com/ebaymotors/Timi...r_Truck_Parts_Accessories&hash=item3f0bfcf474 )

Thanks again, Tony
 






Qs & As

Ok so you time the jackshaft and Crankshaft with number 1 cylinder at TDC on Compression stroke.. Install all guides and sprockets with it at TDC compression stroke. Then install timing cover and balancer before you time the Cams?
The jackshaft is not timed. Each camshaft is individually timed. There are only enough parts in the kit to time one camshaft at a time.

I will probably get a tool kit off of a friend fairly cheap. Will it have the timing procedure or should i use the procedure from the Haynes Manual?
Good luck finding a timing kit to borrow. They are not very common. No, the kit only contains a description of each tool and how to install it. The procedure in the Haynes manual is not very detailed.

What about the balance shaft chain and guide assemblies how are they timed?
If you PM me your email address I will send you the 2005 Mustang SOHC assembly instructions.

Im going to read the threads you posted on previous post.
Click on "Dale's Helpful Threads" in my signature for a list of threads you may be interested in.

EDIT: Do you have the part numbers of any additional parts that are required that is NOT included in the Timing Set like the Sprocket bolts that need to be replaced, and are these parts avaible from local parts house or should they be ordered?
There is a link in my helpful threads to a list. You must buy them from the dealer. The camshaft sprocket bolts are not torque-to-yield and are therefore reusable. The jackshaft sprocket (front and rear) and the harmonic balancer bolts are torque-to-yield and should not be reused.

And is this the Kit you bought that u could recommend? ( http://cgi.ebay.com/ebaymotors/Timi...r_Truck_Parts_Accessories&hash=item3f0bfcf474 ) No. I bought only Ford OEM parts. See: SOHC V6 Timing Chain Parts Sources

Thanks again, Tony
 






I just finished replacing both cassettes, front jackshaft gear , front crank gear, crank to jackshaft chain, guide and tensioner, balance shaft tensioner and guide, camshaft sprocket bolts etc. It runs great, and I have a tool set(OTC6488) for sale for $150 if interested contact me thomasjermstad@comcast.net
 






I just finished replacing both cassettes, front jackshaft gear , front crank gear, crank to jackshaft chain, guide and tensioner, balance shaft tensioner and guide, camshaft sprocket bolts etc. It runs great, and I have a tool set(OTC6488) for sale for $150 if interested contact me thomasjermstad@comcast.net

Which timing Kit did you purchase? (manufacturer) How does it compare to Cloyes or FORD OEM?
 






ZNLM4ty0tOg

Here is what Ive discovered.. Only question is the best way to determine if it may of jumped time? From the Haynes Manual it says at TDC. The crankshaft Key (Torque Converter Key) will be exactly straight up On Compression Stroke. So i checked that and looked at the valves and they appeared to be closed.

Engine Rotates fine, No hard or start stop action. No teeth on the Sprockets looked rounded off or Broken or what have you. Any input or suggestions will be appreciated. Going to Order the Timing Chain Kit This Week.

If you notice in the video the primary chain guide is still intact and pretty Taught.

Thanks, Tony

Hey, that looks familiar :p
attachment.php

Mine looks like it blew apart tho.
 






Hey, that looks familiar :p
Mine looks like it blew apart tho.

haha that looks identical to what happened with mine.. same Tensioner piece left over.. Apparently this happens too frequently

Any after photos of the new guides and chains installed?

Regards, Tony
 



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hello, I bought Ford parts but would have used the 4usa parts if I had to do again. The price on equiv. Ford parts was about $380.00 + shipping. I also changed both cam sprocket bolts,front and rear jackshaft bolts, crank bolt, front jackshaft and front crank gears and water pump ($230.83 +s/h), Gasket set (ebay) $147.27 and bought tool set ($205.48)subtotal=$963.58 + oil, filter, anti-freeze, hoses, atf, trans filter, new ac drier, freon. Expensive job, and the $250 savings w/ the 4usa timing kit would've helped. I have the practically brand new tool-set for sale for $150 + s/h Tom
 






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