I think the Cambelt on 308GT4 coming apart? | FerrariChat
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I think the Cambelt on 308GT4 coming apart?

Discussion in 'Technical Q&A' started by Noah_AMF, Jun 2, 2014.

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  1. Noah_AMF

    Noah_AMF Karting

    Nov 9, 2013
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    Noah
    #1 Noah_AMF, Jun 2, 2014
    Last edited by a moderator: Sep 7, 2017
    Need some help with a problematic cambelt. When fixing my accelerator cable we noticed a bunch of metallic looking fibers all over the right side of the engine and some scattered elsewhere in the engine bay.

    We couldn't find the source but tonight I was checking out the car and was able to see that the cambelt (part no. 107833) appears to be eaten thru about halfway and all frayed on the right side. Pics below...I've got a clean shot and a red box around the cambelt in the second shot plus some of the fibrous debris that's scattered about and accumlating.

    I can feel it with my fingers and it's like touching a bristled comb. Thoughts on what this is? Faulty belt or one of the cams or some else is out of whack and eating away at the cambelt causing it to fray and come apart?

    I just acquired the car back in April and the previous owner had changed the belts within the last 3 years.

    Thanks for any insight that can help.
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  2. JohnnyS

    JohnnyS F1 World Champ
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    #2 JohnnyS, Jun 2, 2014
    It looks like 1/2 of the belt is fine. I would suspect the belt is not riding correctly and worked it's way in and is rubbing on something getting destroyed in the process. So, I think the belt is fine. I would look at the tensioner to see if it is off center, lost the inside bearing or perhaps a chunk of metal got stuck under the cam cover and is rubbing against the belt.

    Can anyone confirm the cam belt contains metal fibers?
     
  3. Jaeger

    Jaeger Rookie

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    #3 Jaeger, Jun 2, 2014
    Not an expert but= DO NOT START engine!
    You may have dodged destroying engine,
    May need to get looked at.
    Hopefully, you just need new belt service.
     
  4. Noah_AMF

    Noah_AMF Karting

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    #4 Noah_AMF, Jun 2, 2014
    Thanks for the quick reply guys! Yes, belt is toast...something must be out of causing the best to come apart. NOT going to start the car. Going to see if I can change the best myself or get it to a shop in Chicago called Autosprint. Anyone ever dealt with them?

    Thanks again!
     
  5. ztarum

    ztarum Formula 3

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    #5 ztarum, Jun 3, 2014
    Wow! You really dodged a bullet there. Good catch!
     
  6. Brian Harper

    Brian Harper F1 Rookie
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    #6 Brian Harper, Jun 3, 2014
    Last edited by a moderator: Sep 7, 2017
    I would check the lower cam belt drive bearings. These are known to fail. On the early cars the bearing is too far inboard and can't cope with the stress and fails. Later cars the bearing is moved outboard where it is sealed and the grease gets old and the bearing fails.

    If the bearing doesn't hold its proper position perhaps it is angled to drive the belt off track.

    The tensioner bearing could also be bad as mentioned, perhaps also angling the belt off track. I'm very interested to see what you find as the root cause. It looks like you were only a few minutes away from new valves.
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  7. tomoshea

    tomoshea Formula Junior

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    #7 tomoshea, Jun 3, 2014
    Check the locknut in lower cam drive gear, one of mine came loose, kept knocking off the woodruff key and damaged the shaft... Needed a new Lower gear- belt was tracking off as a result
     
  8. yelcab

    yelcab F1 World Champ
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    #8 yelcab, Jun 3, 2014
    If you get lucky and have the right tool, you may not need to pull the engine for that.
     
  9. Noah_AMF

    Noah_AMF Karting

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    #9 Noah_AMF, Jun 3, 2014
    Thanks for all the info everyone. Looking into getting this fixed by a local shop or my neighbor who is a highly qualified mechanic might be a be able to help me change the belts out if he's got time. We'll check to see what it's rubbing up agains (might be that locknut on the lower cam drive gear re: tomoshea's post). Stay tuned...
     
  10. JohnnyS

    JohnnyS F1 World Champ
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    #10 JohnnyS, Jun 10, 2014
    Yes, I've used them and they did a clutch on my 328. Fast and good service.
     

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