How to: - SOHC V6 Timing Chain Inspection & Repair | Page 2 | Ford Explorer Forums - Serious Explorations

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How to: SOHC V6 Timing Chain Inspection & Repair

Prefix for threads which are instructional.
I read about somebody who didn't have the tool to keep the camshaft still so he improvised by loosening a couple of cam bearing caps and slipping some sandpaper in there (yikes!) and torquing the cap down gently.

If it sounds stupid but it works.......
 



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First of all, I want to thank you for this very valuable information. It was a success! Now to put it all back together. Only thing I need now is to figure out the Torque Spec for the Valve Cover. I am re-using the original gasket because it looks fine. Haynes Manual says anywhere from 71 - 88 in/lbs. I always used to hand tighten valve cover gaskets, so what should I do here? Somewhere in the middle?

Thanks again!

TJ
 






Amazingly I found a shop that will do this job for $650.00.. does the head need to be taken off?
 






does the head need to be taken off?

Maybe...Some of the models had a tough time getting the guide out. But if it does, ask the mechanic how much extra it will be and have them show you why they have to take it off. It'll be because the upper cam guide is too large. Fortunately, I didnt have an issue and my guide slid right out, albeit it was a very tight fit.

$650 aint bad. It's a hell of a job to do yourself especially if you dont have the tools. Besides, if a shop does it, theres usually a warranty and you dont have to tear it all back apart again yourself if something happens. If I had the money Id have paid that. Good Luck!
 






wow, thanks for the writeup. 118k miles on my '02 SOHC with no problems so far.
 






Ok I changed both screw in hydraulic tensioners on my 03 v6 because of rattle on cold starts. Seemed good at first but the next day the rattle got worse as in constant while driving even when hot. I replaced the front new tensioner with the old and now seems normal. Could the new one been faulty or was the tension of the new one showing signs of a bad guide?
 






Ok I changed both screw in hydraulic tensioners on my 03 v6 because of rattle on cold starts. Seemed good at first but the next day the rattle got worse as in constant while driving even when hot. I replaced the front new tensioner with the old and now seems normal. Could the new one been faulty or was the tension of the new one showing signs of a bad guide?

The new and old seemed to have the same amount of tension in the spring
 






I have a 1999 ford explorer 4x4 4liter sohc engine.the problem is I have a top left corner rattling noise only makes noise after it warms up. It was started cold and was over tacked,the engine still runs fine,what can t h e problem be?
 






front or back?

. . . I have a top left corner rattling noise only makes noise after it warms up. It was started cold and was over tacked,the engine still runs fine,what can t h e problem be?

By "left" I assume that you mean the driver side. Is the source in the front or rear of the engine?
 






engine noise

It's the top left front.
 






excess valve clearance?

Normally a failed left (driver side) cassette guide or a weak hydraulic tensioner is noisiest when engine is first started. Is the rattling consistent with valve opening/closing frequency? If so, it could be due to a sticking valve or a intermittent defective hydraulic lash adjuster. Maybe your oil pressure is low when the engine warms up. Sometimes an exhaust manifold leak can sound like a rattle. Try listening thru a flexible length of hose to try and pinpoint the source of the rattle.
 






engine noise

I don't think it's a valve problem,if you take filler cap off you can hear the noise really good,if you rev engine when it backs down you can hear intermittent chatter.I t only makes noise after it reaches temp.
 






I just want to thank 2000Street Rod for all of his help.I guess I will have to take it apart to see what could be wrong.Oh well I should be happy it still runs.
 






I believe I know the answers but I need to hear it confirmed before I pronounce it dead.
02 xlt with v-6 , vin E, 169k
auto tran

Compression check on the center left bank cylinder was 126 lbs. Repeated test got 65 on same cylinder. Hearing click sound some times on turning over, sometimes not. Best guess is timing is slipping and pressure change depends on if valves are closing or not.
Highly probable exhaust valve has already struck cylinder and that is the loud click.
Have not pulled right cover yet.

Without special tool restoring timing is Hard? Impossible?
Doesn't matter anyway because the piston is almost certainly highly damaged?
 






Your compression numbers should still be somewhat consistent unless the timing is changing during the compression test. If you can actually still crank it, it probably hasn't skipped more than a tooth or two, so there may not be much damage yet. But I wouldn't keep cranking it. Doing a pressure test (i.e. leakdown test) will tell you even more without having to motor the engine. It's fixable if you are willing to spent the money.

Fixing the timing without the proper tools is possible, but difficult, and I don't recommend trying it. You have to understand the procedure and rig up alternatives to the special tools. It would be better to borrow or buy the tools and then sell them again later for most of the cost. Even buying the tools new is a lot cheaper than what you would have to pay someone else to do the work for you. There are some threads here discussing methods of doing it without the tools if you really want to go that way.
 






pistons vs valves

The valves are weaker than the pistons. The pistons may still be functional even if the valves aren't. Significant slipped camshaft timing should result in a fairly uniform compression loss for all cylinders in the bank. You need to check at least two cylinders to confirm slipped timing instead of something valve train related for just one cylinder (i.e. broken valve spring, thrown cam follower, etc.). By left bank I assume you're referring to the driver side. If so, the cassette can probably be replaced without pulling the engine. Also, the head can be removed and repaired without pulling the engine. However, in most cases special tools are required to compress valve springs and to time camshafts. If's not a job for a novice unless you have considerable time and an inclination to learn the process before attempting.
 






Thanks for the advice. I am not a novice, I have pulled engines, trans and changed rings and cranks. More time on destroyer pumps, steering gear hydraulics and steam turbines than gas engines. No auto pro either, there is a lot of value in someone doing the same job before being willing to share. It is economic death rather than mechanical death that I am worried about.
Did not do right side because ERG tube is stuck and rear lower cover bolt is rusted round, can't drive on 7 mm socket or start with chisel. Drilling in the vehicle is not going to work.
I could break off corner and replace the cover. Or just ignore right bank and hope for the best?

The left top guide is in pieces, depending upon where chunk was laying I could pick the chain up off the cam gear. Little chips in there too. No longer any question of re-timing or not to me, much more likely than not to have already jumped the chain.

If the engine is apart enough to work the timing it is not much farther to make sure the head does not swallow or burn a damaged valve in a hundred miles even if it passed today? Worry too much or real risk?

How does doing timing chains installed compare to just pulling engine?
 






replace or repair

Many forum members choose to replace the engine with another lower mileage engine rather than repair their original engine with failed cassettes. The reasons are less down time, less special tools and less complicated procedure. However, even if a replacement low mileage engine has a warranty it probably won't cover the cost/time for replacing a defective one. A replacement engine with more than 100K miles could soon experience cassette failure. I chose to fix mine that had a failed right cassette and a failed primary tensioner at 150K miles. If you PM me your email address I'll send you a copy of the SOHC V6 assembly instructions.
 






If the engine is apart enough to work the timing it is not much farther to make sure the head does not swallow or burn a damaged valve in a hundred miles even if it passed today? Worry too much or real risk?

How does doing timing chains installed compare to just pulling engine?

If it were me, I would pull the engine and fix everything out of the vehicle. It's not really that much more stuff to disconnect. Sometimes the extra effort is worth it compared to struggling to work on it in the car. If you can do the labor yourself, I think it is worth doing. It's when you have to pay someone else for labor that the decision gets hard.
 



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Ok, finally enough warm days to finish getting engine out in the unheated garage. Piston contact in post #1 photo is about the same as mine had. Mine hit both intake and exhaust marks. Frankly neither the pistons or valves look like there really is any serious damage. Anybody have any experience actually running after valve/piston hits?

At 169 k I cannot even feel a ridge in the pistons. I am going to check bearings when I clean out the sump. Looks like the rear main seal is beginning to leak a little, perfect timing that way. Wish I could find someone local who still does heads. Got to be someone left.
 






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