Timing Chain Slipped?

[stkline81]

I purchased a 97 xlt sohc a few months ago from a guy who told me the timing chain had broken on him in his driveway. I put the key in it this afternoon after charging the battery & it started up but ran pretty rough. I shut it off after about 10 seconds to prevent further damage to the engine. I can see plastic pieces inside the engine when I take the oil cap off. Did the tensioner break and the timing chain just slip? If this is what happened is it worth fixing?

 

[2000StreetRod]

Overall condition

Whether the vehicle is worth fixing depends on the overall condition, the extent of chain repair required and your ability and willingness to repair it yourself.

Since the engine still runs it is unlikely that the timing has slipped enough to damage the valves. Failure of the primary (crankshaft to jacksaft) timing chain tensioner although noisy rarely results in a signficant timing change. Replacing the primary tensioner requires removal of the front timing cover. It can be done in a weekend and the parts from Ford probably cost about $150 (primary timing chain kit, crankshaft dampener seal and lower oil pan gasket). If you have guide pieces in your head then you should remove the oil pan and clean out the rest of the pieces.

Correction of your indicated failure of the left/front timing guide assembly requires removal of the front timing cover and the left valve cover. A replacement cassette (sprockets, chain & guide asssembly) costs about $75 from Ford.

The only way to determine if the rear/right cassette has failed is to remove the right valve cover and inspect it. Replacing the rear guide assembly requires removal of the engine (preferred) or the transmission for access. The cost of parts is around $100 from Ford.

If the 00M12 kit (upper & lower intake manifold gaskets and improved front tensioner for $50) has never been installed it would be good to perform the installation in conjunction with the timing chain repair.

See My Helpful Threads in my signature for links to timing chain related threads including current part numbers.

 

[stkline81]

I spent part of the day tearing the engine apart. This is the first time I've taken apart an engine so pardon my ignorance. With 2 kids and another on the way I can't afford to take my vehicles to someone else to fix them. I really appreciate the help I've been getting from everyone on this site! Here are some pictures of what the inside looks like.

Pieces in Oil Pan

I'm amazed at how clean it was inside!

I found this pinned in front of the timing chain...hopefully that means there was little to no damage to the engine?

So how difficult/expensive is it to replace that tensioner, guide, and chain? It did run roughly before I started this project.

 

[2000StreetRod]

Look for small flat metal pieces

I suggest that you sift thru the pieces in the pan looking for small, flat strips of metal. If you find any then your primary tensioner has failed as well as your left guide assembly.

I also suggest that you check the screen on the oil pickup tube. It probably has numerous pieces caught in the screen near the outer diameter. I fished mine out with a bent wire but the oil pump was removed at the time. It might be difficult working under the vehicle.

 

[stkline81]

Just looked through the pieces. Only plastic parts in the oil pan.

 

[stkline81]

Sorry for the quality of the pictures. I couldn't find my camera so I had to use my phone instead. The tensioner had worn down a bit from being pinned against the timing chain. This caused some fine metal shavings (finer than glitter). The shavings disintegrate when rubbed between two fingers. This doesn't seem to me like it caused any damage. I cut the oil filter apart & there was very little of the metal shavings in it.

 

[2000StreetRod]

Helpful threads

I think that you will find the following threads helpful:

Timing Chain Pictures!?!

So what causes the death rattle?

CAUTION Make sure you rotate the crankshaft by hand to get #1 piston at TDC on the compression stroke before disconnecting any of the sprockets. That is the correct position to time the camshafts. Also, at that position the left camshaft will stay in position after disconnecting the camshaft sprocket retaining bolt.

You will have to pull the front timing cover in order to replace the left guide assembly. It is not necessary to disconnect any of the power steering lines. See Power steering pump

Nor is it necessary to disconnect any of the air conditioner compressor lines. See A/C compressor

I suggest that you wait on ordering parts until after the front timing cover is removed and you have inspected the primary tensioner.

It will be very difficult (if not impossible) to remove the guide assembly lower retaining bolt without removing the jackshaft sprocket because the bolt is behind the sprocket. If the left camshaft sprocket bolt is loosened or removed then the left camshaft will have to be retimed. If the jackshaft sprocket retaining bolt is loosened then both the left and right camshafts will have to be retimed. The right valve cover must be removed to retime the right camshaft. I suggest that you remove the right valve cover now and determine if the rear guide assembly is serviceable. If it isn't then the engine must be pulled and you may decide not to repair the current engine but purchase a later model engine from a salvage yard.

 

[stkline81]

I have confirmed that the other chains are still functioning. Can I replace my damaged tensioner without having to retime the engine or will I need the timing tools for this job? I'm not in any hurry as this is a 3rd vehicle.

 

[2000StreetRod]

Timing repairs

The damaged front hydraulic tensioner can be replaced without retiming the engine. However, you also need to replace the timing chain guide assembly which will (as a minimum) require removing the front timing cover. How did you determine that the front and rear components are functional? Did you remove the right valve cover and inspect? Did you remove the front timing cover? If you're just basing your determination on the pieces in the pan it may not be accurate.

The timing tool kit (OTC-6488) greatly simplifies timing either camshaft. There are alternatives but using them is more complicated and can be risky. It is difficult to check the left timing without the tools because the timing slot on the camshaft is at the end close to the firewall. As a minimum, the left camshaft timing should be checked after replacing the guide assembly. It is difficult to remove the guide assembly lower mounting bolt without disconnecting the jackshaft sprocket retaining bolt. When the bolt is loosened the right camshaft may rotate due to compressed valve springs to 50 degrees advanced or retarded. Any time the jackshaft sprocket bolt is loosened both camshafts should be retimed.

Since this is a back up vehicle and you're in no hurry I suggest that you remove the right valve cover and front timing cover and determine the condition of all the timing chain related components. You'll probably have to do it anyway just to replace the left guide assembly and retime the camshafts.