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The wide bushed idler arms are usually NOT included in the hydraulic tensioner kit (what do you want for $450?) . Not sure about the new price of these ($75-$100 ea.?); I picked up a used pair a few years ago for $50. You can place a wanted ad in the classifieds.

BTW, there are no seals as such in these tensioners. They act like a hydraulic lifter in that constant oil pressure keeps the clearance at zero while the precisely machined piston allows the oil to bleed out at a controlled rate. An internal spring merely keeps the piston from collapsing in the tensioner bore if there is no oil at all.

I think the only new items on my car are spark plugs, oil and filters .... and on occasion, brake pads.
Sherwood Lee

Old 06-22-2002, 03:48 PM
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Good info, Sherwood.

I *knew* I shouldn't have paraphrased Roland. I didn't get what he was saying.

So here it is. . .Part of Rolands post on the early S Reg;

"Now the pressure fed tensioners have some problematics.

1.) they have as far I could see it the same failure rate alike the normal 930 tensioner. They seem to fail very soon if the oil contains to much dirt. Also there had been a series sold mostly via the aftermarked who failed within several hours.
2.) they need a very proper installation routine if you set your cam timing with them and use them to hold the cam via the chain they will fail very soon.
3.) they also will fail if the engine is runing over 6 bar pressure. The 930 cases have a other oilpump and a modified case, as long the old block isnīt upgraded to the new standard I wouldnīt recomend using them. They will hold very long but will start needing more time to go up after coldstarts and if your overpressurepiston stucks the unit will shot off his vent ball and let colapse the unit.
4.) After several years working on Porsche and listening to hearsay and stories I found the failure rate from the 930 unit is very low much lower then the pressure feed units. In fact I nver had a failed 930 tensioner on my engines but lost several pressure feed units. Failed 930 tensioners had very high milage and those engines also has bad ramps and worn chains keep beating on the unit. I think BA recomend to renew them every 50 000 mls I use to renew them on every time the heads have to come off with is some 100 - 200000 mls for the average driver.

Now print out the thread and show it to your mechanic."
Old 06-22-2002, 04:10 PM
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Well, I trust Roland and his real-world experience more than I trust those carerra tensioners. Especially all of the defective ones. (See the new thread on page one).

I think that going with new 930 tensioners on my '82, which has the wide-bushed idle arms, is going to be best bet. They do not fail and no defective ones I've ever heard of. My originals are fine with 120k miles, but worn ramps are making noise. Obviously carerra tens. are good if you can avoid the defective ones, I just don't think they are better than last SC ones, (930 part#).
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Old 06-22-2002, 10:39 PM
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Well, I couldn't disagree more. There are rumours that there was a quality-control issue a few years ago. Recent chain tensioners have not been returned as defective. Without a doubt, the older-style chain tensioners do fail. This is a given. If you replace them every 50,000 miles, you will reduce your chances of them failing. However, the Carrera chain tensioners are indeed much more reliable (based on the recommendations of just about everyone I've talked to for this new book, including Bruce Anderson)...

I wouldn't base your decision to use or not to use the newer-style chain tensioners on one person's opinion. If it counts for anything, my opinion is that you should use them.

As for the idler arms, they are *not* included in the upgrade kit. This is because not all cars need them. If your car was manufactured after 1980 1/2 then you already have the updated arms. The new arms (definitely worth it) are about $68 each... Look under tensioners in the following web page:

http://www.pelicanparts.com/catalog/shopcart/911M/por_911M_enginC_main.htm

In my opinion, the Carrera chain tensioner upgrade, combined with the proper pre-bleed installation, and the updated idler arms, should offer the best odds on protecting your engine...

-Wayne
Old 06-23-2002, 12:12 PM
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Well, there is no question that either tensioner, or ANY tensioner for that matter, is fine if it does not fail. They all do exactly the same thing. What you call "rumours" of failed carerra tensioners, I call "reports". And they were not all a few years ago, they continue to the present. (See new thread).

I have also read everything I can get my hands on and talked to many experts, plus read hundreds of owners' personal experience on this board and others, I do not recall EVER reading or hearing about a total-failure of the last 930 tensioner. That is certainly not to say that it has never happened, but I have not heard of or seen it. As opposed to many reports of defective oil-fed units. I tell you, though, if I installed either one of them and they failed soon after and damaged my engine, I would sue who ever sold them to me. Fair is fair.

If the oil-fed units had an absolutely bullet-proof record, I'd put them in. For less $ and hassle, I'll just change the ones I have. I think that if everyone changed these every 100k miles, along w/ ramps, you would never hear about this issue again. As it is, it lives on in infamy. My .02.
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Old 06-23-2002, 02:35 PM
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Hello

@speeder

Well i recomend the upgradekits only for engines with the correct oilpump and in clean internal condition.

I donīt see any sens to add them to old worn engines or the pre 77 cars as you can run into problems with them.

( I think those upgrades where mostly done after the original units made noises and then slap on the new stuff and sale the car with a "upgraded" engine, especially in the US the pressure feed units seem to be a indiacation for quality work and maintance )

Now the main problem on the old engines are mostly lack of oilpressure at idle and so the pressurefeed units make noises until they are pumped up again.

A catastrophical failure didnīt showed up.

This is what happend only with the old 901 units and also the 911 units had a higher chance to fail then the 930 units ( all not pressurefeeded ). But the reality is that you will find failed units mostly in engines who had been used extensivly and are short before they had been to have a topendrebuilt anyhow.

( This doesnīt apply to the 69-74 engines as they have better valve guides.)

Said that i know engines who are now over 200 000 mls blasting down the highways and the are internal often in better condition then the garage queens who are used to idle down the driveways and then get WOTet to catch the green light.

Say there is no general rule and milage isnīt milage but whenever the dopend needs arbuilt it is time to renew the tensioners and some other stuff as well.

I use the pressure feed units when the engine is rebuild and then clean inside ( see Waynes engine pics ).

A enginer ebuild runs right now over 10 000 $ with only the base parts & machining. The costumer can chose the tensioners himself. If not presure feeded then new normal 930 units go back in

Anyhow with either tensioner he gets the same warantys.

Especially if the people are short on budget I like to invest the money into maching or a new oilpump rather then a tensioner upgrade kit. They can be added on later.

I had seen some failed pressure feed units and most from them where installed aftermrked and when you opend the engine you could mostly see that someone slapped them in ( sometimes even without the distance ring so the chains can run into the case, shaving off debris wich failed the tensioners and also the rod bearing ) and still all the old stuff in there, old guideramps, worn chains and gears so I always thougt; Hell sure those units go bad.
A other oberservation was that the factory equiped engines never showed problems and if then those engines had been worn down and the oil was in bad condition ( Sometimes a oilchange fixed it )

But then it hit me myself on two cases and both units where supplied by Porsche and not from the aftermarked and I wasnīt sure about my own work quality and phoned around at other Porsche engine rebuilders and well you got a full bunch from oppinions on the subject but most said they also had sometimes "problems" with them.

Grüsse
Old 06-24-2002, 08:16 AM
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Roland,

A simple question, since I have heard Wayne's opinion and value both of yours: I am going to do a top-end on my '82 SC due to a broken head-stud and oil leaks. It will get whatever work on heads that is necessary, new exhaust, oil lines, all seals that can be replaced, etc. Which tensioners would you install if it was your engine? Also, do you agree with statement that 930 tensioners are only safe for 50,000 miles?

Since I (hopefully) have your attention, new rings as well? Goetze? (Assuming P/C are in spec of course?) TIA,
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Old 06-24-2002, 10:39 AM
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I used the Goetze (sp?) rings on cylinders that were no more than .0015" worn anywhere, and the engine burns no oil whatsoever. Risky though, since those rings are harder than most.

And FWIW, I put pressure fed tensioners on the car two years ago. I'm not Roland, though.
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Old 06-24-2002, 12:32 PM
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Thanks, Super. I guess I was thinking that Goetze is OEM, maybe not? I never kept up w/ your rings thread to the end and did not know whether you wound up w/ new rings. Seems pretty common-sense to use new ones if P/C's are OK, (if they're not you replace everything). I would definitely want to use OEM rings, they would be the ones that factory had spec'ed for those cylinders.

BTW, had an interesting(?) experience today. Was driving by the Porsche dealer where I worked 15 yrs. ago, decided to stop for a minute and ask one of the mechanics, (18yrs. same job), what he had seen in the way of tensioner failure. He said that pressure-fed was the ONLY way to go, he'd never heard of one failing. Now before you P.F. guys get too exited, he ALSO said that ALL of the tensioners before P.F. were "the same",(?), that dilivar studs don't break and were not installed until 3.2 motors,(?), that SSI's would "do nothing"(?), never heard of 964 cam upgrade, etc... Asked me, "where do you hear all of this (poop)?" I just said, "never mind", JEEZ those dealer guys are out of touch!!

Did see a nice Guard's Red 996tt w/ the $17k "go faster" engine option, sticker $150k, have to admit it looked OK.
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Old 06-24-2002, 06:02 PM
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Hello

There isnīt a simple black $ white solution.

My guidelines are:

No pressure feeded units to pre 77 engines ( mag cases ) except they are in a good condition or are rebuilt with a new oilpump.

However costumer is king.

The background is that all the failed pressure feeded units I had seen where in those engines.
There are also some other issues relatet to that.
Your oilpressure will drop and most people are scared seeing the oilpressurelight flashing bright at idle. There is a upgrade kit that mounts smaller nozled studs into the block where the feedlines are boltet on.
But you have a significant oil volume loos up to the cam sprayer rail. However with the new synthetic oils this isnīt a real problem. But to go sure you have to check if your cam sprayer rail tube works like they should.

On the 3,0 on engines ( aluminium cases 5 bar oilinstrument ) everything is ready to bolt on the pressure feeded units.

If your engine shows internal wear we have to talk about it and make following desicion.

Using the pressure feeded units now and risk a problem with them and dump them later when the engine is on time for a rebuilt.
Or just renew the normal 930 units and use the Pressure feed units after a clean rebuilt.

If it is a budget issue then I rather spend money into a idler arm, drive gears if they are worn and in the chain ramps. Any pre 1980 engine should have renewed the ramps if they still have the originals. The pre 69 rubberized units are contaminting the engine with that rubber and your cams run dry ( using the pressure feeded units on those engines isnīt helpfull ). Pre 78 ramps are geting brittle over the years and can snap. This mostly blocks the cam on the side and shears them off. Fixing a chain tensioner failure is cheaper.

If the budget isnīt on shortage I also recomend the pressure feeded units. But the reality is that most Porsche owners are "growing" with there cars. They want the best cut for the money. My goal is to keep the costumer happy plus his car into my hands. A engine failure is mostly the end from the relation as they loose confidence or canīt afford the rebuilt

Any new tensioner is better then waiting for the failing unit.

Now on the lifetime from the normal units.
I know cars with very high milages and still the original units in the car. I talked to those owners about the potentional risks but they think I try to sale something to them so they drive untill the unit makes sounds. Hell some from them are over 200 000 mls and potentional costumers

The 50 000 mls cycle is a good number to stay on the safe side.
If you remove them you will find them mostly a bit soft but not real soft.
It is the same thing like on the belt driven Porsches. You can expand the belt service but sooner or later you will have problems yet sometimes you have belt failures even before scedule.

Now if it would be my engine I would go for pressure feeded units as they are the more clever design and prolong the lifcycle from your timing chain.
But if it would be my engine and didnīt be in the condition the pressure feeded units needs then i would use the normal units.

Thinking about it I had more sleepless nights with the pressure feeded units then with the normal units.

Grüsse
Old 06-25-2002, 01:03 AM
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When they look like this.
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File Type: jpg collapsed chain tensioner right.jpg (33.5 KB, 1703 views)
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Old 06-25-2002, 03:17 AM
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jadams, great pic...here is my failed one! I am saving $$$ to fix this little mess. By inspection, how do you know if you have the "better" idler arms? Or does this only apply to the Carrera chain tensioner update? What is an idler arm?
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Old 06-25-2002, 04:33 AM
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Kemo, the later style spocket arms were introduced in 1980 1/2. Engines with a serial number after *6300454* had them. The later arms have two separate bronze bushings. I upgraded to the later style arms when I did mine.
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Old 06-25-2002, 05:39 AM
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Hello

The correct idler arms ( or chain wheel carrier arm ? ) have bronce bushings. The old versions are just drilled holes in the GGG cast.
If you have old idler arms then also check the pivot for wear.

Sometimes they have grooves and need a bit smothing. Sometomes they are oval and need to be renewed.

Grüsse

Old 06-25-2002, 03:07 PM
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