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Kenny Z.
Kenny Z., Ford Senior Master Tech
Category: Ford
Satisfied Customers: 5210
Experience:  Auto Trans, Drivability and Electrical Specialist
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How do I set the front timing chain gears on a 98 explorer 4.0 sohc?

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how do I set the front timing chain gears on a 98 explorer 4.0 sohc?

HiCustomer I am John Mc, a Ford dealer technician.
I hope I can help solve your problem quickly and accurately.


You absolutely have to have a special set of tools to set the timing on these trucks. No way around it. These tools position the cams and the crank in the proper position and then you tighten up all the bolts. This set of tools lists for around $600. I usually suggest for you to prepare every thing for the job, remove the valve covers, the timing cover and install the crank pulley and take it to a dealer. They will usually charge an hour or two of labor to do the job. This is much cheaper than the tools! Another option is to talk to one of the techs and see if they will come to you and time it. Offer to pay $100 and they should be glad to do it. I will post the instructions so you can see what all is involved.


Click here for instructions.


I hope this answer has been helpful to you! If you have any further questions please feel free to ask.

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John Mc

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Customer: replied 6 years ago.
am only replacing the front chain and tentioner. need to make sure top and bottom gears are aligned properly. there are no timing marks to go by. how do I check this setting?

You have to set all the cams when you take anything in the timing chains loose. You have to have the tool set.


Sorry for the bad news but it is what it is.

Customer: replied 6 years ago.
Sorry but thats not true since other mechanics I've talked to have done it without your tools. I'll take there experiance over what the book says.Sorry to waste your time.
If you want to bend valves by guessing go ahead. I do all the timing setups on sohc motors in my shop and there is not accurate way to do this without using the tools. If you are willing to tear up a $2500 engine to save a little money, go for it... It won't hurt me, my Explorer runs!
I have replaced the front primary jackshaft chain,guide and tensioner many times without timing the cams. If you already took the bolt out of the jackshaft gear then you are in trouble. There is a trick to replacing the primary chain without locking the cams down with the tools. This engine will only stop in three places one of which is with the keyway on the crank at 12 o'clock. The engine is in a neutral position as far as being able to loosen the jackshaft bolt without the cams springing to another position. I usually pull the front cover, rotate the crank until the keyway is at 12 o'clock. At this point I mark 2 chain links and one tooth between them on the front cam chain and do the same for the jackshaft chain and gear ( which is essentially the rear cam chain). The jackshaft sprocket is not keyed to the jackshaft. Now I hold the crankshaft stationary and loosen the jackshaft bolt. Nothing should move at this point and you can replace the gears,chain and guides. Only hand tighten the jackshaft bolt to where it is almost contacting the gear.Once I have the chain, guides and tensioner all installed and the making sure all my marks are still good I then hold the crankshaft and snug up the jackshaft bolt until the gear cannot move independently of the shaft. I now release the tensioner. At this point I hold the crank again and torque the torque to yield bolt on the jack shaft. This is the improper way to do this but it can be done and I have done it many many times on this engine for the tsb ford had out for rattling from the primary chain. If you loosened the jackshaft bolt before lining up the crank and marking the gears and chains then you will need the tool kit. If the jackshaft moved independently of the jackshaft gear then the engine will need to be timed from scratch.
Kenny Z., Ford Senior Master Tech
Category: Ford
Satisfied Customers: 5210
Experience: Auto Trans, Drivability and Electrical Specialist
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