Sudden Chain Tensioner Spring Wear

[BruceMcC]

A couple months ago I removed the timing chain tensioner spring to install an offset woodruff key. I didn't get the right offset so last weekend did the job again and got the right offset key in there.

When I removed the spring this time, there were significant wear areas on the outside of the spring. Serious wear, like something was rubbing badly.

On previous inspection two months ago, the spring was in pristine condition.

What did I do wrong???? I've ordered a replacement spring, but something is not right that I should have so much wear in such a short time.

Bruce McCreary
'85 300D
Snowflake, AZ

[Pete Burton]

Did you take the tensioner apart and reset it? Make sure you follow the procedure when you replace that inexpensive spring.

[Eskimo]

Sorry, no answer here, but another question:

When you put the spring back in the tensioner, did you use a new sealing ring? If so, where did you purchase the ring? This part is on my shopping list.

[BruceMcC]

Pete, no I did not remove the tensioner, only the spring per the manual.

Eskimo- Sorry, I reused the aluminum washer as it was still OK. Let me know if you find it.

My usual trick for aluminum washers is to make it with some 1/16" sheet stock, a step drill, then tin snips, and a file. Barbaric but it only takes about 15 minutes to do a decent job.

I"m just going to put in a new spring and check it after a while.

Bruce

[BruceMcC]

I got a request for info on the woodruff key job.
Pull the valve cover, pull the fan and shroud (or have someone crank from below), crank on the crank to line up the timing mark behind the timing gear. Read your degrees of strech- should be 1-4 degrees past zero. Pick an offset woodruff key that's half your stretch. (2 degrees woodruff for 4 degrees of stretch).

When it's time to put in the new key, do the same as above, then remove the bolt on the timing gear per the manual. Loosen the chain guide bolt which faces forward so the guide can be pulled forward. Remove the chain tensioner spring per the manual. Now you can grab the timing gear and pull it forward off the shaft. WATCH OUT- you need to keep an eye on the timing mark disk- it's like a big keyed washer. DONT DROP IT IN THE CRANKCASE. I stuff rags around the timing gear for insurance. Carefully remove the timing mark disk. Remove the woodruff key with a needle nose vise grip plier or a small vice grip, torture with a punch as needed. The key will be at around 2 o'clock.

The new wooduff key has a flange that faces to the left as you're standing in front of the car thinking about it.

Put in the new key, put on the timing mark disk, then the gear and bolt. Don't forget to put in the chain tensioner spring before you check your timing and of course crank it around twice.

Cranking from above with the fan and shroud removed is a snap. But the fan bolts require a ground thin box wrench and are not very awkward to get out and in. And you have to crank from below to get it out. BUT then you can do the whole job by yourself easily.

Remember that if you use an offset woodruff key, it only corrects for valve timing, not your injection pump. So you need to retime your IP too. Which isn't too bad. I like the air version of the drip method.

Bruce McCreary
(2) '85 300Ds, '83 300CD