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Picture inside. I have a question about timing marks

Discussion in 'Boxers/TR/M' started by silvergts1998, Nov 17, 2007.

  1. silvergts1998

    silvergts1998 Formula 3

    Apr 10, 2005
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    #1 silvergts1998, Nov 17, 2007
    Last edited by a moderator: Sep 7, 2017
    I was putting my engine on TDC and used the factory marks. What I noticed on the exhaust side of the cam, I had two marks on it. is this right? Doesn't look right? Is there a reason why there are two marks?
    maybe I am missing something here, but I would think there should only be one mark.
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  3. 2NA

    2NA F1 World Champ
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    Possibly one is a "remark" because the other was off a bit.

    Possibly both are wrong.

    Time for a degree wheel and dial indicator.
     
  4. silvergts1998

    silvergts1998 Formula 3

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    That what I was thinking, it was a mark that was off and then remarked. I am not going to mess with it, my car was running fine so I will leave it where it's at. In the future, if I rebuild the engine, I will mess with it then.
     
  5. 2NA

    2NA F1 World Champ
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    In the photo you show one of the marks in alignment. are the other marks lined up as well?

    I think you're "good to go".

    A lot of attention is paid here to degreeing cams whenever timing belts are changed (just look at the million timing belt threads). In my experience while for absolutely optimum performance it is good to use a degree wheel and "dial everything in", I've never had an engine that didn't run well because the factory marks were off.

    Chances are good it will run okay at either mark but maybe 2% better at one of them.
     
  6. carguy

    carguy F1 Rookie

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    Hmm....never seen that before. I've just seen the usual one single mark on the cam. I the past when I used a degree wheel I found the factory timing marks were spot-on with TDC and the valve opening/closing events. The cap notch is wider then the camshaft mark, so you can vary a little and still be within the width of the cap notch. I measured this and it turns out it takes just under 3 degrees of crankshaft rotation to use the entire width of the cap notch, which of course is only 1.5 camshaft degrees....not enough camshaft rotation to worry about. I would imagine that cam lobe events combined with the timing belt slack/tension during cam rotation varies the timing by a degree or two anyway.

    Has anyone ever seen 2 marks like that? Are the 2 marks supposed to line up with each edge of the cap notch - that way there is no "that's close enough" sort of judgement call? I would really like to know about this.
     
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  8. james patterson

    james patterson Formula Junior
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    Most if not all the early 512 TR's had the cams marked grossly incorrect. The mark that is off is the original mark, someone marked it again during the coarse of a service. The cars left the factory with the one mark that was way off. If you are doing a belt service you should degree the cams as mentioned.
     
  9. tvu

    tvu Formula 3
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    I just had my 30K major done a few months ago, and the engine was really wobbly at idle. After some troubleshooting, they figured they had to pull the engine out to check out the timing/marking. Sure enough, they were dead on with the factory marking. So they had to resort to the old fashion way with the degree wheel etc... Needless to say, they weren't too happy with Ferrari, but they said this was the first time they have found a mismarking - However going forward, they will take that extra time to check with the degree wheel before putting everything back together.

    BTW, mine is a 92 - so maybe that explains it.

    ps. They remarked it also, and made a note on it so in the future, the 30K service would be a lot easier.
     
  10. carguy

    carguy F1 Rookie

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    This just blows my mind that the FACTORY marks would be off. That would mean that in order to make the car run right, they had to do a degree-wheel job themselves, and could see first-hand that the original "builder's marks" were off....so it would make sense to put a second mark into the camshaft. But how would you differentiate the two later on when doing a service? How would you know which was right and which was wrong? Mr. Patterson speaks from lots experience about this, and I feel TVU verifies this fact. If.......or when I ever get a 512TR I now know what to watch for. I do seem to remember in the past where some 512TR owners had a service done and experienced erratic or reduced performance afterwards.

    Thank You SILVER1998GTS (Adam) for bringing this to our attention....this is invaluable information.
     
  11. silvergts1998

    silvergts1998 Formula 3

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    My car idled perfectly, but will have it double checked with a degree wheel. This is why I strongly recommend taking a picture of everything with a digital camera for future documentation.
     
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