brand new oil-fed chain tensioner gone bad

[ckissick]

After about 200 miles on my new engine with new oil-fed chain tensioners, a low-rpm noise developed on the left (driver) side. I was in Campbell, so I swung by Jerry Woods, and he identified the noise as a failed chain tensioner.

I'm going to take it apart and inpsect it, but I was just curious... How common is it for a new chain tensioner upgrade to go bad? It was installed by one of the best in SoCal, so I don't think the installation was the cause.

Charlie
1970 911E
1950 VW

[Rot 911]

I know a couple of years ago there was a batch of bad oil-fed tensioners being sold.

[sammyg2]

(warning, severe sarcasm ahead
In the past three years or so I can remember reading about at least a dozen failed new carrera style tensioners.
Funny thing is, I can't remember reading about a single failed earlier style unit. That can't be right, I must have missed them. There had to be at least several thousand failed earlier types reported in that time frame or everyone wouldn't be saying that the upgrade is manditory.
(end of sarcasm)

Sorry for hyjacking your thread, but yes. Many people have reported new oil-fed tensiners failing. I too have heard it was due to a bad batch, apparently that was one very big batch.

That is exactly why I did not "upgrade" to these units. I don't buy the hype and respectfully disagree with those who say it is a "must do".
Yes, all early tensioners will eventually fail. All oil-fed tensioners will also eventually fail. The trick is figuring out which style will fail earlier and which will last longer.
Based on the reported evidence it looks like the new style isn't living up to their reputation.
The safety ring thingies are all I need (knock on wood).

[Zeke]

I use safety collars, Sam. You're not the only one. I'm thinking of going to solid tensioners, I don't have any problem with goin in and checking/adusting them every few 1000 miles. It'll take me a while to rack up even 5000 miles. Like a year.

[ckissick]

Now that you mention it, my new engine replaces a 1974 2.7 with very high miles, very bad compression, bad leak down numbers, and oil leaks that had Greenpeace activists following me with signs. And the original tensioners were just fine, thank you.

I will say, however, that my engine was not damaged, I guess because of the spring acting as a backup. When the old style tensioner fails, the noise that tips you off must be a tad louder as the pistons crush valves.

Charlie

[ckissick]

I just took off the chain cover to inspect the problem, and found no problem. The chain is tight, and there's a lot of clearance between the idler arm and the housing, so that's not hitting anything. And I could not move the plunger on the chain tensioner.

I put everything back together, and the noise was gone for about 20 miles, then came back. Then it went away again.

My conclusion: the tensioner is only bad intermittently, and I will replace it. I was just wondering, has anybody else had an experience like this?

Charlie

[Slider79SC]

I had my drivers side fail on me and it turned out to be plugged. We cleared it with a little solvent and compressed air. No problems since.

[vol96]

I've always wanted to upgrade to the new style tensioners. But then I remember how low the oil pressure gets at idle and reconsider. I dont know the internal design of the new style but I suppose they dont require constant oil pressure or there would be more problems with them. The old style (051's) never caused any damage.......either with my 73E which I owned for 13yrs and 50k miles or my 72E which I owned for 12yrs and 40k miles.

To me the important feature of any tensioner is how much warning you get before it completely fails and causes damage. Dont know which style give you the most.

[Joeaksa]

Had one fail on me 50 klicks after installing it. Turned out to be clogged as well...

JoeA

[ckissick]

Can you unclog it while installed?

Charlie

[alex jelepis]

Off and on chain noise in my '71T - driving me nuts, cool Fall weather (Ohio) seems to affect it as it has been pretty quiet lately. Seemed worse this Summer.

Will have the covers off over next couple of weeks to check things out. Wrench warned me not to drive, but I've taken more than a few chances lately and probably pushed my luck as the noise has been absent, but a failure could occur anytime.

Debating upgrade or sticking w/ originals. Just purchased an extra pair of '70 tensioners from e-bay seller who claims they had 68K. They look good, but plunger do not depress at all. Is this normal? Seems to me that I could place enough presssure to cause movement - probably need rebuilding.

Any thoughts?

Thanks....Alex

[competentone]

Originally posted by vol96
I've always wanted to upgrade to the new style tensioners. But then I remember how low the oil pressure gets at idle and reconsider. I dont know the internal design of the new style but I suppose they dont require constant oil pressure or there would be more problems with them.

Somebody correct me if I'm wrong, but isn't the hydraulic tensioner actually a mechanical tensioner with the oil pressure working to keep tension if the spring fails? It's a redundant system -- which adds the extra margin of safety against failure. (My wife, looking over my shoulder, just commented that my comment "extra margin of safety against failure" is redundant too! )

[dtw]

Originally posted by competentone
Somebody correct me if I'm wrong, but isn't the hydraulic tensioner actually a mechanical tensioner with the oil pressure working to keep tension if the spring fails? It's a redundant system -- which adds the extra margin of safety against failure. (My wife, looking over my shoulder, just commented that my comment "extra margin of safety against failure" is redundant too! )

No. Try completely purging the oil from a tensioner, then compressing the plunger. The spring offers very little resistance.