Chain Tensioners Rebuilt?

[aigel]

Oh, I completely forgot! When did the idler bases become wide on the 3.0? Was this in 80 or 81? This is definitely an upgrade that needs to be done. The narrow base can lead to the idler cocking and failing the tensioners also! Please someone who knows post the info! THANKS!

Cheers, George

[andycook]

OK, so help me out here. Yet another P-Car amateur doing my own wrenchin. I am rebuidling my 78 3.0. My intent is not to dirve it every day. More of a garage queen. Do I or do I not need the upgrades? Can I rebuild my standard tensioners and install the "crash collars" for backup? I could sure use th $400 elsewhere at this point. Thanks.

[HarryD]

Originally posted by andycook
OK, so help me out here. Yet another P-Car amateur doing my own wrenchin. I am rebuidling my 78 3.0. My intent is not to dirve it every day. More of a garage queen. Do I or do I not need the upgrades? Can I rebuild my standard tensioners and install the "crash collars" for backup? I could sure use th $400 elsewhere at this point. Thanks.

You need to do your own research and make up your own mind. However, what I have "heard":

1-The problem with the failures has several sources: The older idler pulleys can bind. This was solved first with spacer and later with a redesigner idler arm.
2-The timing chains have some strange harmonics at the 2-3000 rpm range which overwork the tensioners leading to premature failures. This became evident in the 3.0 and larger engines since you were actually able to drive the car for extended periods at these lower rpms and still have some "grunt" when you needed it.

I am no expert ,so the true experts here can correct me if I am mistaken.

As often stated, the upgrade is good insurance, but you have decide if it is worth the cost. When my tensioners were changed to carrera tensioners, my wrench noted that some (not all) of the chain ramps were changed and the tensioners have a 930 number so they are the upgraded tensioners as well. They were perfectly fine when they were removed but I wanted the "extra piece of mind".

YMMV

[aigel]

andy:

I think if you have the collars and your tensioners in good shape with the wide idlers, you shoudl be all set.

Note that a LOT of people will look for the carrera upgrade when they buy an earlier car. It can be a thing to do if you plan on selling the car in the not so far future.

George

[markwemple]

I am cheap and, ince I have seen carrera failures, I would rather go early with collars. I can't remember whether it was 80 or 81 but that upgrade should be done. As far a catastrophes go here is a good story: When I bought my '76 I was a newcomer to the 911s (knew 356s then). I knew of a really good wrench about 300 miles away so I made a vacation out of it. I decided to let him go throught the car, including putting collars on. So I was visiting a friend when, under deceleration, my 911 made a noise that sounded like dieseling! I called him, described the noise and he said to take it easy and come up asap. So, I left a day early and drove about 250 miles with this unknown condition. Even hit the redline a few times but never "raced it." When I arrived he gave it a quick lesson and went into the back of the shop. He came out with a couple of tensioners (used from a carrera update) and said "here." SO there you go. Nothing fatal is definite just possible.