Carrera vs Turbo chain tensioners
 

I've got a '71T thats making alot of noise on the drivers side chain tensioner area so, I've been reading every thread I can regarding chain tensioner upgrades. There's alot of info out there on this upgrade and 99% of these threads are regarding the carrera tensioner variety. I read so many last night that I thought I came across a post in a thread that mentioned the turbo tensioner was a more reliable way to go...now I can't find it.:confused:

Can someone share the pros and cons on the 2 different upgrades please?SmileWavy I know the Carrera is pressure fed with oil lines and the turbo has an oil catch at the top (can't find a picture of the part in the pelican catalog). From my understanding the 911 turbo doesn't use oil feed lines for the tensioner because of space constraints and they built in a collars as a fail safe.

There are differing opinions among engine builders (Really?:rolleyes:)

If you want a stock look, you should go 930 tensioner. They are sealed and have the bushing upgrade on the idler arm. They do not use the outside oil pressure lines that can leak. These are very reliable because of the bushing and lack of oil leaks. Put the safety collars on.

Carreras are nice, too, but the outside oil lines are non-stock and can leak. If you go this route, you can do the modification to prevent total collapse where a pin/stopper is inserted behind the piston and spring. If you cannot find the thread with this procedure, please post.

Both tensioners are spring tensioned with an oil damper. It is just how the oil is delivered/kept there.

The most important thing is to get new tensioners and chain ramps (especially if you have the old soft plastic kind). 930s are great with collars. So are Carreras. Just don't leave a bad tensioner in the engine.

After replacing my 2.7's pressure-fed tensioners with new ones (on advice from my "gurus"!?!), if I had it to do over again, I believe I'd opt for the 930 tensioners with the "collars" - which (1) are very reliable (I've been told); and (2) don't affect oil pressure.

I'm happy to sell you my old Carrera tensioners which I believe are fine although I'd highly recommend the modificaton mentioned above. Refer to

http://www.pelicanparts.com/techarticles/911_Carrera_chain_tensioners/911_Carrera_chain_tensioners2.htm

If you go with the Carrera tensioners, I believe the oil line restricter is also recommended (PEL-CAMRSTN).

There is much debate about the cam tower oil line restrictors. I personally don't like them but I may be wrong. More knowledgable people can chime in.

Flieger and Conrad thanks for your replies. Im leaning towards the turbo tensioners for the reasons you both mentioned.

Conrad, thanks for letting me know your Carrera tensioners are available. If I decide to go in that direction I'll certainly pm you.

Flieger, I remember reading there's another fail safe where a brass bushing/tube is inserted inside the tensioner housing that, in essence, increases the shaft length thereby not allowing the shaft to "collapse" beyond a certain point and thus maintaining chain tension. This doesn't sound like the idler arm bushing you refer to but more like the "pin stopper" you mentioned. Did I confuse this?

http://forums.pelicanparts.com/showthread.php?s=&threadid=199819&perpage=20&pagen umber=3

Original appearance for concours= 930

Don't care about looks = Carrera

When you do ANY tensioner mod you have to get the updated idler arms, these are not cheap. Also remember that the old sealed tensioners have a thicker boss that goes over the pin, these must be machined or replaced with the newer, thinner versions, that work with the updated idler arms. Also make sure the pins aren't galled, Tim Hancock has a good thread on how he replaced his with drill rod.

What's nice about the 930 tensioners is that they are rebuildable. Put collars on them and you are good to go. I perfer these over the "carrera" tensioners.

There's another reason 930 tensioners are superior, the word from somebody who
really knows what they are talking about is that carrera tensioners aren't reliable
above 7000rpm.

andy

Sand_man, that thread is exactly what I was trying to describe - the Jerry Woods update(bookmarked it). Thanks!

John, thanks for idler arm info. Will definitely read Tim's write up! Also, although not planning to make this a concours car, you never know...

Aaron, good to know they're rebuildable...another reason to go with the turbo tensioners. thx

Thanks for additional info Andy. Came back to thread and didn't recall seeing your reply.

This is the first I've heard of that. It goes against what I've seen on our club race engines and those of other clubs, some of them run to 8500 RPM. Is there a reason why this would be so?

-Andy (the other one)

I also prefer the 930 tensioners with collars to Carrera tensioners especially on early mag case. Since the advent of Carrera tensioners we are seeing far more case distortion at the intermediate bearing. Is this distortion caused by pressure fed tensioners? I'm not certain but it's worth considering.
The other problem with pressure fed tensioners is their propensity for line leaks. The oil lines seems very leak prone and the small steel lines break with sometime catastrophic results. One of our rally cars line /broke a line and the whole rear of the car caught on fire.

The real problem with early tensioners is narrow non bush tensioner arms. They tend to bind on the shaft causing premature failure of both styles of tensioners. (Carrera & 930)

Turbo tensioners with wide tensioner arms and collars is the way to go.

Because of the hi cost of wide tensioner arms( $250+ ea) and the great availability of early narrow arms we have started to convert the early arms for use on all our rebuilds.

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How do you attach that spacer to the idler arm? Is it a big bushing turned down on the idler
end and pressed into the arm?

andy

Henry, how wide is the insert, end to end?

great stuff Henry!

The arm is machined out and the bushing is pressed in and honed to size.
The bushing is the full width of the arm body plus the spacer width, making the dimensions the same as a Carrera tensioner arm.

We are not interested in competing with Pelican Parts for the sale of any parts, so please check with their sales desk before contacting us for any parts.

These items were not designed and manufactured for resale. We needed a better part for our rebuilds so we made one. Because of the intense interest in this product we will sell the pair of arms for $190.00 exchange. plus shipping and sale tax
As with all our custom parts, these carry a life time warranty for the original purchaser. I know from previous posts that this life time warranty has little or no value to some of you so those of you with this perspective can just ignore it.:)

FWIW, I just pulled a perfectly good set of Carrera tensioners for the rebuild of my '69S motor...again for the "correct" look only. For my center lubed '65, they were the only option, too. They really are nice with the collars.

Yes, the Carrera tensioners are available for purchase. :D

Henry are you able to show a picture of the 930 tensioner with
the arm machined for the wider idler arm?

andy

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