Strange chain tensioners
Thread Starter
2nd Gear
Joined: Jun 2006
Posts: 2
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From: South San Francisco, CA.
Strange chain tensioners
Well, here's my first post!, Quick intro, new owner of a 67 912 that has a 70 911 engine. Looks to be a well done conversion. Body is straight, no rust! Any way I'm hearing a scraping type noise from the right chain housing and immediatly think colapsed tensioner. Pull the cover and see a "updated" full mechanical tensioner!
What do you all think of this set-up? It's definetly noisy. If I stay with it, how often should I check for chain strech? How do you know you have enough tension? This car otherwise seems to have been well sorted out.
Thanks Dave
P.S. Look forward to hanging out here!
What do you all think of this set-up? It's definetly noisy. If I stay with it, how often should I check for chain strech? How do you know you have enough tension? This car otherwise seems to have been well sorted out.
Thanks Dave
P.S. Look forward to hanging out here!
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Rennlist Member
Rennlist Member
Joined: Aug 2003
Posts: 4,146
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From: Raleigh, NC & North Myrtle Beach, SC
I think that is a regular chain tensioner, converted to mechanical. I am no expert, but they have to adjusted fairly often, and I am unsure of chain tension needed. SOmeone on the board I'm sure can help. I had tehm on my 72E and didn't like them becuse of the lack of flexibility and the worry of chain tightness. They won't collapse, however. I would change to the latest pressure fed ASAP. It is a fairly inexpensive (relative term) and straight forward process.
Rennlist Member
Joined: Oct 2004
Posts: 20,607
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From: Bakersfield, CA, for now...
Throw them away - they're JUNK! 911 timing chains stretch approximately 2mm between cold start and full temp. Obviously, a "mechanical" tensioner can not accomodate this stretch, so the chain is either too loose or too tight depending on temp and how the tensioner is adjusted. Your tensioners are similar to putting a bandaid on a wound that requires stitches...
Pete
Pete
RL Technical Advisor
Joined: May 2001
Posts: 11,870
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From: Portland Oregon
Originally Posted by Peter Zimmermann
Throw them away - they're JUNK! 911 timing chains stretch approximately 2mm between cold start and full temp. Obviously, a "mechanical" tensioner can not accomodate this stretch, so the chain is either too loose or too tight depending on temp and how the tensioner is adjusted. Your tensioners are similar to putting a bandaid on a wound that requires stitches...
Pete
Pete
Convert the engine to Carrera pressurized ones with the late wide idlers and you'll have a reliable setup that won't let you down.
Replace the chain ramps, too.
