The authoritative thread on chain tensioners

[jrbennett]

930 tensioner part number should be 930.105.053.00
I believe you'll also need a spacer for each tensioner, part number 930.105.513.00

[gled49]

The idler arms should be updated as this was shown to be a contributing factor in tensioner failure. And the idler sprockets and axles should be replaced as they look like non-bushed sprockets, anybody had one seize up, I have, not pretty. Gordon

[911scfanatic]

This is a very simple and rewarding upgrade. Definitely a DIY job if you feel comfortable.
I did it a couple of years ago on my '68 after one of the original tensioners collapsed. Caught it before a catastrophic failure.
Rebuilt the 930 tensioners with a rebuild kit (don't know if they still sell them; procedure is in the FWSM), put in some Carrera idlers and collars.
Great project and very well documented on The Bird.

[66S]

The idler arms in early aluminum motors have bushed idler arms and seldom gall the pins. You do not need later arms but the wider bushings are an improvement. I prefer solid tensioners, 930 tensioners can fail that's why the factory replaced them with the more reliable Carrera tensioners. It's not a good idea to let your car roll backwards in a forward gear with hydraulic tensioners, it can retract them.

[gled49]

I was referring to the non bushed chain wheels that are mounted on the idler arms. Solid tensioners will accelerate chain stretch and wear as the engine lengthens when it heats and the chains don't. Gordon

[Kilgore Trout]

Maybe beating a dead horse here... I have scanned several threads on this subject, and STILL have questions.

1. What is the difference between the older and newer 930 tensioner?
2. Do you need the spacer with both the older and newer versions?
3. I understand the "idler arm" is an issue, but will the 930 tensioner with older,(original) version of the idler arm be a benifit?
4. I am calling the idler arm the part that the tensioner puts tension on, is that correct?

I am looking at some, part # 930.105.501.OR, for what looks like a good price. I feel like I should not pass them up?

Thanks,
Dan

[edmayo]

#1 may be a terminology issue, basically the difference between "old" and "new" is the width of the casting that fits on the idler arm post.
old tensioner is thick and can only be used with earlier "thin" idler arms. Newer tensioner is thinner on that mounting ear so it can accept
the later wider idler arms. If you used a later "thin" tensioner with the old narrow idler arms, a spacer was required to make up the
difference.
#2 The best solution is the later thin boss tensioner with the later wide base idler arms,,,,and a guard on the tensioner. Compared to the sixties
and seventies tensioner failure is virtually a thing of the past.

[Kilgore Trout]

Thanks Ed, that is helpful. I bought a pair of 930.105.501.OR ,$100.00 for the pair. It didn't seem like I could go to wrong at that price.
My engine is out of the car, so before I put it back in I can check on what I have and check the chain ramps. I expect to see a part number starting with 901. I have already added the safety collars.
Dan

[crummasel]

Basically further than the narrow "ear" to accept the wider idler arms, the latest non-Carrera chain tensioners had an imho very important detail change, a spring loaded check valve inside.
Rebuild kits have them included so with that also an older chain tensioner with the non-spring-loaded check valve (with the thicker "ear") can be updated.
That should be done in any way.
I never have seen one of these later ones collapse on a huge number of engines i was working on, but the older version sometimes, which have sucked air...

[al agustin]

This is a very simple and rewarding upgrade. Definitely a DIY job if you feel comfortable.
I did it a couple of years ago on my '68 after one of the original tensioners collapsed. Caught it before a catastrophic failure.
Rebuilt the 930 tensioners with a rebuild kit (don't know if they still sell them; procedure is in the FWSM), put in some Carrera idlers and collars.
Great project and very well documented on The Bird.

Would you please be so kind and post the various part numbers of the items you purchased for your 68 and other associated things I need to order that would be for good measure. I also have a 1968 2.0 engine but all this never ending amount of information and opinions is making me lose my mind Thanks very much!

I just bought a complete chain tensioner rebuild kit and now I don't even know if they would work...
These are the items I bought:
https://www.pelicanparts.com/More_In...105-901-01-OEM
https://www.pelicanparts.com/More_In...-0458-053-M230