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Rubber Tensioner

Discussion in '"Stock" Alpine' started by dlyle123, Oct 23, 2010.

  1. dlyle123

    dlyle123 Donation Time

    How many have had problems with the reproduction rubber tensioners? I recently bought one from a reputable parts supplier and installed it in my engine. I drove the car for a couple hundred miles before deciding it needed a complete rebuild. When I took it apart I was shocked to see how swollen the "new" tensioner was. I have no oil additives and clean oil. I had a similar experience with the last rubber tensioner too. Both were soft rubber when they came out and were swollen to a scary size.

    I've searched the forum and it seems a few other people suspect these are bad reproductions. Some even say to use the original. I'm a little scared to use the reproductions now and am thinking of going back to the steel one that my car originally had. Sure they're a little louder but I'm not sure I want to take the chances of the rubber one failing.

    Thanks, Doug
  2. jumpinjan

    jumpinjan Bronze Level Sponsor

    Any Alpine engine that I rebuild, I use the original rubber tensioner. Yes, the engines that I tear down, I find them swollen too. One I found in the oil pan, and it was a huge lump.
  3. dlyle123

    dlyle123 Donation Time

    Thanks for letting know Jan. This is actually a Minx motor so if I can't find what looks like a good original rubber piece I'll use the steel blade that the early Hillmans used.
  4. puff4

    puff4 Diamond Level Sponsor

  5. dlyle123

    dlyle123 Donation Time

    Yeah, it's experimental. I think I've already been the test dummy so I'm not going there again. I just may go back to the steel blade.
  6. RootesRacer

    RootesRacer Donation Time

    Not sure where you bought your tensioner from, but I have bought several from SS, and havent had a problem at all with them.

    I know of several others that also bought them from SS, and they swelled up like a dead cow on a hot day.

    Goes to show there are some good ones and some bad ones out there.

    You might ask the supplier if this is the attribute that differentiates his product from the rest.
  7. dlyle123

    dlyle123 Donation Time

    I bought mine from SS. I've got one in the garage...I'm going to put it in a cup with some oil and see what happens.
  8. RootesRacer

    RootesRacer Donation Time

    Hot oil, cold oil will take forever.

    In fact, put it in 50/50 new and used oil just to be sure the chemicals that swell it are present.
  9. sammaw@bellsout

    sammaw@bellsout Silver Level Sponsor

    I had this happen on one from SS, after less than 600 miles. I ordered another from them and VB, and they seemed similar. I ended up putting the original old one back in.
  10. sunbeam74

    sunbeam74 Silver Level Sponsor

    Running a test might not take too long in hot oil this issue occured happened within 600 miles. Figure an average speed of 30mph and you'd be looking at 20 hours actual engine running time. The other variable is the time it was just in a static mode in the assembled engine.

    If you can find a safe place to warm the oil up to 180-190 F it might be worth trying to cycle the rubber tensioner through temperature a number of times to a total period of 20 hours.

    Take a few dimensions before and at time intervals.

    It seems like who ever is producing these clearly used the wrong material.
    Apparently all the vendors are sourcing these from the same place.

  11. Alpine 1789

    Alpine 1789 SAOCA President Diamond Level Sponsor

    What are the symptoms of one that has failed?
  12. sunbeam74

    sunbeam74 Silver Level Sponsor

    I would like to ask if anybody could send their failed (swollen) tensioner to me? Would anyone have pictures they could send too?

    Let me know if you can help out.

    Steve Silverstein
    130 Chase Road
    Marlboro, MA 01752
  13. dlyle123

    dlyle123 Donation Time

    The first tensioner on my car failed after less than 100 miles and the second one was 200 or so miles. Maybe failure isn't the correct description as the rubber did not come apart but rather just swelled to huge proportions. At those dimensions they are getting squeezed between the cam timing gear and the timing cover so it would just be a matter of time before it came apart. As of now I can't bring myself to put another one of those rubber pieces back in there.
  14. jumpinjan

    jumpinjan Bronze Level Sponsor

    Another big problem with the new rubber tensioners, that no one has mentioned yet, is that many new ones are NOT molded right and so they don't fit right.
  15. dlyle123

    dlyle123 Donation Time

    photos added

    Here are a few pictures of one of the rubber tensioners that came out of my car. The smaller one is unused but is still the wrong soft rubber. I thought I had thrown away the enlarged one but just found it in the garage. The swelling doesn't seem as bad as I remember but it may have shrunk in the last year.

    The size it is currently would have soon caused it to come apart as it was getting squeezed between the cam gear and timing cover. Look at the picture from the top and you can see that the chain was starting to tear it apart. It is still very soft.

    I've decided to put the engine back together with a used rubber tensioner out of an old Alpine. It seems to be in great shape compared to everything else I have seen. I'll keep an eye out for rubber particles when I change the oil.

    Attached Files:

  16. JConstable

    JConstable Donation Time

    A quick question....has there been any resolution to the tensioner problem? Or is it still advisable to use an old tensioner? Thanks John
  17. tigretr

    tigretr Platinum Level Sponsor

    Ditto on the swollen tensioner. In 2005 I put a new tensioner I got from SS in my motor. I few hundred miles later I was in the timing cover for reasons other then the tensioner, but when I took the cover off I noticed the tensioner was so swollen that there were chunks missing from it. No longer able to trust the new tensioners, I went down the long road of installing a timing belt. I did however look into creating a nylon or other material tensioner. I took a new tensioner, wrapped it in fiber glass and installed it in my motor. Once dry I took it out and was left with the installed shape of the tensioner. I then took a hundred or so data points off the profile so I could create a solid model. Got that far, looked into the PV (Pressure / Velocity) of different materials and decided to go the belt route. If someone is interested in being a guinea pig I might be willing to revisit this and make some parts for you. I would probably do it just for the cost of materials. Anything to get away from the rubber. Let me know.

  18. Q

    Q Donation Time

    Still finding swollen rubber tensioners

    What is the feeling in 2013 regarding the quality of the tensioner rubber? I'm working on fixing the timing cover leak and pulled a broken, chain worn, slimy swollen black slug of a rubber tensioner from my 1966 sV that was re-built in the 2000's tonight. Luckily, I had ordered parts from Sunbeam Specialties today and included a replacement. On inquiry regarding this problem I was told that they figured the problem had been solved based on the lack of complaints they were receiving. Is the aftermarket problem with tensioner rubber solved?:confused:
  19. 65beam

    65beam Donation Time


    one of the first things to remember is not to use high mileage oils or synthetics in your alpine engine since the tensioner is a chunk of natural rubber. these oils are blended to swell worn seals and since the tensioner is rubber it swells also.
  20. jumpinjan

    jumpinjan Bronze Level Sponsor

    The best solution for me is to re-use the factory rubber tensioner.
    (Fact- I haven't seen a factory tensioner that was swollen as bad as the new replacements they sell today. Don't throw them away)

    Last edited: Sep 24, 2013

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