355 major gas tank out | Page 2 | FerrariChat

355 major gas tank out

Discussion in '348/355' started by NMF1, Oct 21, 2020.

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  1. Jackie and bill

    Jackie and bill Formula Junior

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    You dont have to tell me anything about the 355 brother. But thanks for the effort.
     
  2. KevZep

    KevZep Formula Junior

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    Okay thanks I'll try to remember that......
     
  3. Ferrarium

    Ferrarium F1 Veteran
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    I ask because every time I ask someone who time the cams they say that when they were finished timing it the timing marks were the same meaning those assembly marks aren't some rough gauge they're fairly accurate. after all it was done at the factory when they were set. I'm sure some vary like a Friday at 4pm car so it's a good idea to check.

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  4. KevZep

    KevZep Formula Junior

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    Kevin Bennett
    Yes they'll get you in the ball park, but as the timing gear is using a belt, they are obviously adjustable to account for any variances there may be. It is fair to say they are reasonably accurate though.
     
  5. johnk...

    johnk... F1 World Champ
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    #30 johnk..., Oct 22, 2020
    Last edited: Oct 22, 2020
    No argument here. Belts stretch a little. Another reason for hydraulic tensioner as opposed to the old fix tensioners use don the 3x8 series. But I would argue that performance is necessarily degraded. Performance is changed. you may gain in one RPM range and loose in another. It's not straight forward. Another issue is that belts are elastic so regardless of whether they undergo permanent deformation due to stretch, they do stretch under load and the load on the belts is variable with not only with RPM but also with rate of change of RPM. This is another reason they now use hydraulic tensioners as opposed to fix tensioners. So what ever the static timing is, it's constantly changing by some amount when the engine is running.

    I was unclear here. I should not have used the word "correct" as what I meant was "previous" timing..... If you installed a new belt and the timing was off more than that associated with belt length tolerance it is because of 1 of 2 things. 1) Who ever timed it last screwed up. This is a reason why you are probably better off if you leave things as they came from the factory. The assumption is that the factory got it right. So leave it alone. By timing the cam every belt change you are relying on the ability of the mechanic to do it at least as accurately as the last guy. 2) The other way the timing could be different after a belt replacement, again, by more than belt length tolerances, is mechanical wear. If there is wear it doesn't matter what you do. Depending on how timing is done either opening, closing, position of max lift or some combination of two of the three will be off.

    Now, if you found your exhaust cams off 3 and 6 degrees after a belt change, the last guy to time the cams screwed up or the exhaust cams are shot. In either case, apparently you didn't notice any drivability issues because of it.

    Take my car. The belts are 8 years/11k mile sold. The car runs more than acceptably to me. Starts, good throttle response, passes emissions. I could not care less about what the actually cam timing is. I don't lay awake nights thinking about it. When I have the belts done I'll be more than happy if it runs as it does now. I could care less about peak performance. And if it's timed perfectly at the belt change, in a year the timing will be off because of belt stretch.

    So it's up to the owner as to what he wants to do. But it's not a matter of necessity.
     
  6. tbakowsky

    tbakowsky F1 World Champ
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    I have attempted to do the tank out method in the past. Yes is can be done. However I would not do it again. Those plastic lines leading to the tank, filler
    neck, vent tubes, are getting very old and brittle, and are unavailable. Risk is very high of damage or breakage.

    The a/c lines crossing in front of the left timing cover require quite a bit of "manoeuvring" to get the cover off.

    Front crank pulley removal requires the engine and transmission mounts to be loosened completely and the entire assembly be slid back as far a possible..which isn't much. A shallow 36mm socket and a long breaker bar is needed to lossen the bolt. Hopefully the last guy didn't use lock tight on it..

    Removing the vlave covers in the car is not a bad job..but is not fun either. Leaning over the body work of a car only increases the chance of dents and scratches. My back hurts just thinking about it.

    Setting cam timing would be near impossible.

    You can do it, but the risks are pretty high. If you are a penny pincher ferrari owner..its an option. If you want it done right..it is not.
     
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  7. yelcab

    yelcab F1 World Champ
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    I no longer debate the point. I do it my way.
     
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  8. KevZep

    KevZep Formula Junior

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    Fair call, I appreciate the response and the time you took to clarify.

    "In either case, apparently you didn't notice any drivability issues because of it." In actual fact I did, which is why I checked the cam timing before I took the belt off.
    But was the noticeable difference afterwards the new fuel pumps, spark plugs, and so forth, well, we dont really know, but I do know after tuning countless engines on the dyno, cam timing makes a difference. Its not right or wrong in terms of performance, its different as you say.
     
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  9. jjtjr

    jjtjr Formula Junior

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    I think this sentiment is relative to the thoughts of about 90% of Ferrari owners(and all other makes/models). We all just want our cars to
    I think this is the sentiment with 90% of Ferrari owners (and most other makes/models), we all just want our cars to run well and enjoy driving them. I know that there are professional mechanics that will sell customers on the fact that they degree every engine belt job they do, but I'm sure a camry owner might say "what?", while a Ferrari owner will say "that's awesome". I think when any cambelt engine is spinning at 6K plus RPM, a half-of-a-degree of cam timing due to belt stretch is probably acceptable from an engineering perspective.
     
  10. Ferrarium

    Ferrarium F1 Veteran
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    #35 Ferrarium, Oct 23, 2020
    Last edited: Oct 23, 2020
    Hence my argument that those "assembly marks" are probably quite adequate and of course you wont bend valves that that one video showed "accidently" on purpose.

    I get some folks may want to check and have it exact that that's fine, but saying not doing so puts folks and their engines in mortal danger is absurd. Your not saying that, no one here is, I know... but some folks are militant about timing cams even after you slam the door hard. :)

    Timing your cams is not needed people, do it if you must of course it likely a good idea, but if you don't there is no shame, those marks are just freaking fine. It was fine when you took the belt off assuming you checked that first.

    #CamTimingShaming :p
     
  11. johnk...

    johnk... F1 World Champ
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    My point is simple. You have been driving your car for 3, 5, 10, 15 years with out a problem. You are not going to suddenly have a problem related to cam timing if you lock and swap. If you anal about it, if you a professional shop with potential liability, fine, degree the cams. But one other point is that every time you unlock the cams there a chance that an error will be made.

    In the context of this thread, with the limited space and access to all components needed to degree the cams I would suggest the chances of error grow and you are probably better off doing a lock and swap if you are dumb enough to drop the tank.
     
  12. KevZep

    KevZep Formula Junior

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    I'm not talking about whether you want it done or if you care about it or even if it makes a difference.
    The facts are, Ferrari made the cams adjustable, unlike a Toyota Camry, and they outline the procedure for dialing the cams in whenever the belt is being replaced or that part of the engine is being assembled.
    This is good enough reason to do it.
    If you line the assembly marks up, the cam timing can still be off, I deliberately took extra time to make sure the marks were as close to perfect as possible on my engine in reassembly.
    The result was one exhaust cam off by 3˚ and the other by 6˚. Was it someone else messing it up last time? Is it because the marks are not set to the exact timing? Who knows.......Again, this is good enough reason to do it.
    How do you know your cam timing is right if you don't check it?
    Ferrari never refer to those marks as "timing" marks, they are referred to as "assembly" marks.

    I understand a lot of people are doing their own work, and may not have a couple of dial gauges and the knowledge to dial cams, other feel its not necessary, and that is all fine, its a free world and you're entitled to make you own decisions.
    But, the procedure outlined by Ferrari is to dial the cam timing in, I happen to agree with this, and so I check the timing.
    When I do a Toyota Camry, I do not do this as there is no provision to dial the cams in the first place. So this is an easy decision.

    For me I feel I at least want to check it, who knows what the last guy did in there, maybe the last guy thought he was a bit of a legend and advanced the inlets or something to make it "better", so in this case the assembly marks are not going to give you the full story of where the timing is at, although, they will have your engine running without breaking or bending anything. Yeah, I feel its worth at least checking to verify.

    I am not criticizing anyone for not doing it, I am just pointing out what Ferrari expect you to do, whether you think its right wrong, necessary, or witchcraft, that's up to you, and more power for you doing your cambelt change and saving some $$....
    Happy days, but at least be informed, have a think about it and maybe learn something new, I like dialing in cams, there is something satisfying about it, knowing that everything is spot on.
     
  13. johnk...

    johnk... F1 World Champ
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    Actually, Ferrari does not say to time the cams at each belt change. The instructions for timing are for assembly from scratch. For a belt change here is what Ferrari says, outlined in red, in the 360 manual for service (not assembly). The 355 and 308 manuals address assembly only. Now, we all know that the timing marks won't necessarily line up perfectly. The comment in red is to be interpreted as an indication that the marks should be close.

    Basically what they are saying is lock and swap. Time only if obviously off. And note, it doesn't even say retime. It say "check". But those who are in the "degree the cams at every belt change" school of thought dismiss this.

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  14. KevZep

    KevZep Formula Junior

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    This is what I am saying,
    For me I feel I at least want to check it, who knows what the last guy did in there, maybe the last guy thought he was a bit of a legend and advanced the inlets or something to make it "better", so in this case the assembly marks are not going to give you the full story of where the timing is at, although, they will have your engine running without breaking or bending anything. Yeah, I feel its worth at least checking to verify.

    You can interpret it any way you want, but at the end of the day Ferrari want you to check it.

    I think we are actually agreeing with each other.
    Check it or don't check it, use the assembly marks as timing marks and hope the last guy in there didn't screw it up or mess with it, whatever, its up to the individual and what you want to do at the end of the day....
    I am not trying to start an argument or say anyone is right or wrong, but rather trying put forward considerations so people can make their own informed decisions, its nothing to do with being "right" or "wrong".
     
  15. Jackie and bill

    Jackie and bill Formula Junior

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    These exact arguments and facts were around 15 years ago, word for word. Theres is nothing unique in what anyone has said in this thread.
    History repeating its self , it seems like it's a yearly event.
     
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  16. johnk...

    johnk... F1 World Champ
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    And most prevalent in the 348/355 section. Seldom comes up in the 3x8 section where lock and swap is routine.
     
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  17. Ferrarium

    Ferrarium F1 Veteran
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