Tensioner Questions for 72 911T

I have a 72 911T with around 30k on a rebuilt motor. It has original chain tensioners. 2 mechanics have told me two very different things.

Mechanic one told me that the original chain tensioners scare him and he wants to upgrade them before impending disaster occurs.

Mechanic two told me that the original tensioners are fine and in 30 years he has rarely seen a problem with them.

Who's wrong?

I have full receipts on the engine rebuild.

My understanding is that a good re-build included replacing the tensioners and a cheap-o job would not have.

What would I look for in my engine re-build recepits to determine if the mechanic replaced the old tensioners?

Any info here is appreciated.

I have heard both stories from different mechanics too. I went ahead with the pressure fed tensioners. It was only about $150.00 more for the pressure fed verses original. My originals had just started to make noise at 129,000 miles. If they replaced the tensioners on your rebuild they should be listed on the invoice (about $200.00 for parts). If they weren't replaced you might think about replacing them. In hindsight I think the original tensioners will suffice. I had a reputable Porsche mech tell me he has seen very few problems with the original tensioners. If you feel queezy about em, put some collars on the ones you have. That would prevent a total collapse. I did the upgrade myself, the toughest thing was wrestling with the muffler. Good luck.

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Robert Stoll
83 SC
83 944

Would there be other parts on the receipt in conjunction with the tensioners themselves that would give me some idea of what's currently in there?

Ian,

The two most important parts associated with tensioners are the two double-bushing idler wheel or chain sprocket carriers: 930.105.509.00 & 930.105.510.00.

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Warren Hall
1973 911S Targa

Maybe chain ramps too.

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Robert Stoll
83 SC
83 944

Bruce Anderson *constantly* says in his tech articles that the updated idler arms and wheels (introduced in 1980) solved 90% of the tensioner failure problem, as it was binding of the early style idlers, NOT the design of the non-pressure fed tensioners, that was the real problem.
Of course, he also says that the pressure fed tens cured close to the remaining 10% of the problem.
FWIW.

Warren, thanks for the info. I don't see those part#'s on my records. This list is not for the meek. I have had this car for 2 years. It runs great.

Can you spot any areas that might be suspect based on the list of parts in the rebuild?

I see the following major parts in the rebuild. I left out things like nuts and washers, studs etc. Part #'s may not be 100% accurate, they are hard to read in a few places.

Here it is:

2 Chains 90110552950
1 Filter 9010776400
2 Hoses 90121119400
3 Shaft 901110534204
3 Rockers 90110504300
3 In. Valve 91110541100
6 Stud 99906200602
1 Piston/Cyl Kit 91110392102
9 Guides 90110432151
1 "not legible" set 91110090500
6 rails 91110522205
3 ex. valves 91110541500
2 Tensioners 93010549?(part# is hard to read)
3 Guides 930010432150
2 Guides 93010432150
3 Valves 91110541100
6 "no part name" 93010432150

The description of the work is "Disassemble engine to case, replace pistons and cylinders, sublet heads for re-building"

The rebuild was done in 1984, by the Porsche/Audi dealer (it's gone now) and the car has around 25k on the new engine. The Mechanical injection has also been completely overhauled (all injectors have been replaced, the pump and governor was completely overhauled by Jerry Fairchild Industries.

I apologize for this ridiculous post, but where else are you going to get this kind of info these days.

Thanks.

Check out our technical article, with pictures of the Carrera chain tensioners installed. If you don't have these oil lines, then you don't have the chain tensioners.

http://www.pelicanparts.com/techarticles/911_carrera_chain_tensioners/911_carrera_chain_tensioners2.htm

Also, we have these in stock right now for $395...

-Wayne