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? Type Tensioners for 67s Rebuild??

My 67 911s engine is being assembled. My builder has suggested to use later style chain housing in order to use hydraulic tensioners. My problems is that I want to keep the external appearance of the engine factory original. I am not keen on having these hydraulic lines show as this will detract from the car's originality.

The early cup style tensioners are out of the question as these are very prone to failure and take time to build up pressure.

What is the consensus out there with early 911 owners?

Mike
Old 03-06-2005, 04:51 PM
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Reliability is more important than originality IMHO.
Old 03-06-2005, 05:08 PM
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I am definitely not in the experienced camp here - so I am sure others who are more knowledgable will chime in.
But, on my '67S, I have mechanical tensioners, which seems to be generally hated by many.
That said, many or most pre '68 cars here are with this setup for the reason you mention - keeping the stock look.

Both my original engine rebuilder and my current mechanic who has rebuilt many engines believe the mechanical (modified to be solid) is the way to go with the really early 911s. They both say that with a cover off adjustment every so often such as setup is fine. Since my car is only driven once per week I guess this isn't a problem.

I hope other posters will not shoot the messenger here, as I am only relaying views in my neck of the woods and I know your question touches on a topic that has reached a virtual religious zenith on these boards. You should also check out what the guys on the Early 911S board think in regards to impact on originality and value.
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Old 03-06-2005, 05:12 PM
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Why not go with mech tensioners, but install collars in case of failure?
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Old 03-06-2005, 07:18 PM
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Mechanical with either collars or the 'Jerry Woods Mod'. The mod is detailed in the post from 'aigel' about halfway through this thread.

Last edited by Shuie; 03-06-2005 at 08:02 PM..
Old 03-06-2005, 07:59 PM
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idler arms were updated around '80; some people think it is nearly as important as the pressurized stuff. Of course the non-pressurized tensioners improved over time as well. Perhaps a replica of the '80-83 setup would be a good starting point.
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Last edited by KobaltBlau; 03-06-2005 at 08:09 PM..
Old 03-06-2005, 08:04 PM
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I built a 67 "S"engine some years ago and installed pressure fed tensioners. I had both stock covers machined for the hole so the tensioner could stick through. The only custome part was one of the cam feed lines. I can't recall but I think I had to modify the side with the distributor. I took the stock line and had to lengthen it alittle. All in all it wasn't that difficult. Hope this helps.
Old 03-06-2005, 08:14 PM
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Quote:
Originally posted by KobaltBlau
idler arms were updated around '80; some people think it is nearly as important as the pressurized stuff. Of course the non-pressurized tensioners improved over time as well. Perhaps a replica of the '80-83 setup would be a good starting point.
I agree totally with Andy's assessment.
Late style arms with 930 tensioners and a chain saver kit and you're good to go.
My 2 cents worth=
"On an early "S" engine stock appearance is important."
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Old 03-07-2005, 07:29 AM
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There are definitions being used that is causing some confusion. First by definition a mechanical tensioner is solid. The mechanic , breaks loose a jam nut makes the adjustment and locks it down again, much like in adjusting valve lash on the 911, so there for a safety coller is unneeded.
Second the sealed tensioners have oil in them for the buffering effect like a shock damperner, so they or hydro. tensioners and they self adjust. when the oil leaks out the damping effect goes away and cam timing suffers, under sever conditions the chain can skip teeth and valve/ piston contact is possiable. safety collors help in preventing big failure. but they do last enough time to still be a popular choice.
3rd style use engine oil to provide pressure and damping effect they do not have rubber seals and their main fault lies in im proper instalation, which seems to be not bleeding them before start up and not secureing the oil lines from vibration to prevent steel fatigue and then ruptue of oil.
There is a late model sealed hyd. tensioner that many people use with early engine refered to as the "930 style" which is the most advanced sealed hyd. tensioner. Fritz
Old 03-07-2005, 08:08 AM
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No further convincing needed. No hydraulic tensioner oil lines for this engine. I will go with the 80-83 "930" style with collars.

Thanks all!
Old 03-08-2005, 07:13 PM
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Hmm. the Jerry Woods Mod is also a good alternative to collars.
Old 03-08-2005, 07:22 PM
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Hi

There is a lot of BS about tensioners, If you want a stock look fine, go for the later non "pressure refreshed" tensioners and use collars or drop a ball bearing in the bottom (The "Jerry Woods Mod") either solution is preferable to mech tensioners. either way its not like your early 911 drove out of the factory and had tensioner failure 5K down the road, it was more like 100,000K, so all this 'tensioner failure' angst is crap. My early 911 failure was caused by the original rubber/wire chain rails collapsing, I wouldn't rebuild early tensioners but if you are concerned carry a spare pair they only take a couple of hours to change

HTH

Neven
Old 03-10-2005, 01:28 AM
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I have used the origional with collars for years. Survived one failure. Having said that I believe the updated are probably the the most bullet proof
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Old 03-10-2005, 01:26 PM
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