Replace timing chains ?
 

OK, I know Waynes book says a new master link chain is better than an old chain but just want to double check everybodys feelings on this.
This is a 78 3.0 liter with 74K miles, Tope end being redone due to Dilavar issues. Everything looks fine , heads are getting Supertec care and cams/rockers redone by John Dougherty. I have already replaced the chain ramps and am upgrading to the later idler arms. No wear on the sprockets but have a replacement set anyway. On teardown the tensioners did not appear to be extended very far, for whatever that is worth.

Just wanting to make sure before I pop out the original chain and put in the master link style (which are sitting on the bench)

When I did my 92 I just used new chains. What is a master link chain?

I would definitely. Pelican doesnt seem to have it for a 78. I got mine from this site www.performancepartsstore.com along with a bunch of other stuff. Great prices and service. Here's your part:

http://www.performancepartsstore.com/item.wws?mfr=IWIS&sku=POR022916&price=37.81&orpart no=1198950&cookieID=1PF0ZFFWX1QN0TSE3F&drillid=9&i mage=

A search
on Pelican finds this part as the first item listed.

If the chain is not stretched (elongated), use the old chain. It's not so good to use a new chain with old sprockets (inner sprocket).
74k is nothing it will last the double.

Saying that, I replaced my chains when my chains where so elongated that my tensioned almost touched the housing on the left side. It has held up 10-15k miles now, but I think its a gamble...

I have never heard of a master-link chain failing. Has anyone else?

I didn't see that they were the same PN. Pelican has it mislabelled as for up to MY73. Probably should read 1983.

bbh03..that is kind of what is am wondering. I sure see how a master link could be the "weak link" but have always wondered if this is one of those things we always worry about but rarely occur?

I have seen a few bike chains failing on the track, not sure that it is the link failing or improper fitment or other links failing.......however look at bikes the punishment these take are huge! I would have though that the chances of failure of the timing chain are very small indeed, the load could not be anything like driving a rear wheel.

Mark.....

Well, if Wayne's opinion means anything to you, he claims it is better to use the masterlink than to leave the old chain in his book. So I guess you have to make a decision based on that vs. the other feedback here.

"Safe",
How do you tell if the chain is elongated?

-Eric
90 C2

Usually if the chain is elongated, you can lift it away from the sprocket as you hold the opposite site firm, but if your sprocket is worn, it will be hard to tell. As far as the master link goes, I think failure is rare, but I remember being told in school that the direction of the opening on the closure is important. It should face away from the direction of rotation. Just another 2 cents.

I dont think that a master link chain is weaker, if you put the lock "thing" on the right way.
Erik: My idler arm on the left side was very close to the housing => tensioner close to its max extension.

Found a picture.
On the right side its more difficult to see if the chain are elongated.

http://forums.pelicanparts.com/uploa...1140717737.jpg

I would not replace it unless it is streched. To me its best to not replace it until are doing complete rebuild.

Good luck.

I had the same question a few months back.. I even had two master link chains ready to go in. After a long look at the amount of travel the chain tensioners still had until they bottomed out and the amount the existing chains had stretched (if any) I left well enough alone and did not replace them.

How many miles were on the motor Steve?

Only 30k Miles, but it was difficult to say that they were genuine. The odometer had not worked in the vehicle for al least the three previous years. All the service records dating back to 2000 said 24,000km. I estimated by the wear on the brake rotors that it had at least double that or 30k miles