interference versus noninterference engine??

Discussion in 'Prime Main Forum (2017-Current)' started by bear15, Jun 3, 2017.

  1. bisco

    bisco cookie crumbler

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    i wonder if the service manual would have the answer.
     
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  2. bear15

    bear15 Member

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    Awesome- I think we might be getting closer. I have not had a chance to watch the video yet. Do you know if the 1.8L 7AFE, 4AFE, 4AF – Non Interference listed below is the engine in the prii???

    Interference Engines – Complete List
    The following list will provide you the information on whether your car engine is an interference engine or a non-interference engine. An interference engine is one that has insufficient clearance between the valves and pistons if the cam stops turning due to a broken timing belt. The result is usually catastrophic engine failure. Not so with a non-interference engine. It pays to know.
    The video below will also help you determine if your car has a timing belt or chain.


    Toyota

    1.5L (1A-C, 3A-C & 3E) Interference
    • 1.5L (3E-E & 5E-FE) Non-Interference
    • 1.6L DOHC (4A-F & 4A-FE) Non-Interference
    • 1.6L DOHC (4A-GE & 4A-GZE) Non-Interference
    • 1.6L SOHC Non-Interference
    • 1.8L Diesel Interference
    • 1.8L DOHC Gasoline Interference
    1.8L 7AFE, 4AFE, 4AF – Non Interference
    • 2.0L Non-Interference
    • 2.2L Diesel Interference
    • 2.2L Gasoline Non-Interference
    • 2.4L Diesel Interference
    • 2.5L Non-Interference
    • 2.8L Non-Interference
    • 3.0L Inline 6 (Except 1998 2JZ-GE) Non-Interference
    • 3.0L Inline 6 VVT-i (1998 2JZ-GE) Interference
    • 3.0L V6 Non-Interference
    • 3.3L 3MZ-FE V6 W/ V VTi – Interference
    • 3.4L Non-Interference
    * 3.5L V-6 Non-Interference
    • 4.7L Interference



     
  3. Mendel Leisk

    Mendel Leisk Sidewalk Supervisor

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  4. fuzzy1

    fuzzy1 Senior Member

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    With all current systems of mechanically driven valves that I've heard about, a timing belt/chain/gear is essential. This may go away some time in the future when all-electric valves come into play, but that has not yet happened.
     
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  5. dalcon95

    dalcon95 Senior Member

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    Screenshot_20170603-152624.png
    This is what engine is currently being used in the 4th generation Prius. Being it isn't a 7AFE, 4AFE, or 4AF, that tells me that it is an interfering engine.

    #1 in Easley,SC
     
  6. PT Guy

    PT Guy Active Member

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    Whether or not it is an interference engine is almost a moot question due to the great reliability of the timing chain. I won't worry about mine. In any case, what are you going to do?...renew the chain every, what?, 200,000 engine miles or so? That would be about 500,000 miles on our Prime. We won't live that long. Neither will the Prime.

    I had a 2001 Tundra 4.7 V8 with one of Toyota's very few belt equipped interference engines. Every 90k that engine got a new timing belt. Long ago I had an old Chev V8 where one side plate of one link came loose and was banging the cover until I replaced the chain. But, that was long, long ago, and it was a Chevy.:(
     
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  7. bear15

    bear15 Member

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    Well, for the sake of interest as it relates to this thread/topic, it looks like we will need to find another list for verification as this one does not include the Toyota 2ZR-FXE 1.8 engine that is used in the Prii as indicated above. I wonder if a good Toyota service manager might be able to help answer this question.

    Toyota


    1.5L (1A-C, 3A-C & 3E) Interference
    • 1.5L (3E-E & 5E-FE) Non-Interference
    • 1.6L DOHC (4A-F & 4A-FE) Non-Interference
    • 1.6L DOHC (4A-GE & 4A-GZE) Non-Interference
    • 1.6L SOHC Non-Interference
    • 1.8L Diesel Interference
    • 1.8L DOHC Gasoline Interference
    1.8L 7AFE, 4AFE, 4AF – Non Interference
    • 2.0L Non-Interference
    • 2.2L Diesel Interference
    • 2.2L Gasoline Non-Interference
    • 2.4L Diesel Interference
    • 2.5L Non-Interference
    • 2.8L Non-Interference
    • 3.0L Inline 6 (Except 1998 2JZ-GE) Non-Interference
    • 3.0L Inline 6 VVT-i (1998 2JZ-GE) Interference
    • 3.0L V6 Non-Interference
    • 3.3L 3MZ-FE V6 W/ V VTi – Interference
    • 3.4L Non-Interference
    * 3.5L V-6 Non-Interference
    • 4.7L Interference
     
  8. ChapmanF

    ChapmanF Senior Member

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    This isn't the first time this question's gone around PriusChat ... the last time I remember seeing it, there was someone reporting a pattern with Toyota engine designs: the non-interference models use belts, the interference designs use chains. I don't remember who said that or on what authority, but it did seem to make a bit of sense.

    -Chap
     
  9. bear15

    bear15 Member

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    Hi Chap- Thanks for the input, but this still does not answer the question as related to this thread. Although we might be getting closer. Many thanks!!

     
  10. ChapmanF

    ChapmanF Senior Member

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    I wonder what you would consider to "answer the question as related to this thread"?

    You included a list a couple of posts up:

    You bolded the line for 7AFE, 4AFE, and 4AF—all engines the Prius doesn't have. The Prius has a 2ZR, which is not mentioned by name in that list, but it is a 1.8L DOHC Gasoline engine, which matches the line above the one you bolded. You mention a 2003 Highlander engine being non-interference, but not which available 2003 Highlander engine you knew that about. I assume you may have meant the 1MZ 3.0L, because the 3MZ 3.3L is shown in your list as an interference design. 3MZ does have VVT-i, and this article claims the engines were non-interference "before the 1999-2003 introduction of VVTI") The 2ZR engine in the Prime also has VVT-i.

    To get the closest to a positive answer to your question, you might sign into techinfo.toyota.com and look through the engine mechanical section for the model year of Prime that interests you. You would be looking for telltale instructions like these:
    int.png

    Those are from the 1st generation Prius, 1NZ engine manual, just to give you the drift. They don't want you ever to rotate the crank when the cams won't rotate with it—except in rules 2 and 3, where you are to rotate the crank 40° backwards (enough to move all pistons away from TDC) before you turn any cams ... and, when it's time to undo that, make sure the cams are back in matchmarked position first, then rotate the crank back where it belongs.

    That was in the valve-clearance adjustment section for 1NZ. I'm not sure you'll find a valve-clearance adjustment section for 2NZ given that it has hydraulic adjusters. But you might look through the various other sections having to do with cam or head removal, etc. If you find instructions like that, you'll pretty much have your answer. :)

    -Chap
     
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  11. bear15

    bear15 Member

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    Thank you for the information- very helpful information. And I have personally learned a ton or related information as part of this thread which has been awesome. As indicated in the first post, this thread is simply looking for verification if the gas engine in the 2017 Prime is an interference or noninterference engine. I hope this helps.

     
  12. ChapmanF

    ChapmanF Senior Member

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    What would you consider verification, beyond what is already in this thread? If that isn't enough for you, there will probably be no verification short of you going to the repair manual and looking for a specific passage like the 1NZ passage I quoted above.

    -Chap
     
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  13. bear15

    bear15 Member

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    I will try calling a few local service managers and see what they recommend in terms of verification-- maybe even speak with one of the senior tech guys. I travel approx. 5,000 miles per month, a little over 60,000 miles per year and so this is somewhat important information for some of us (see post 9,561 in 60 days). I hope this helps.

     
  14. Sam Spade

    Sam Spade Senior Member

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    Hope it helps what exactly ??

    I think you just have an un-natural obsession with this interference question.

    You already found out that it has a chain, not a belt.
    AND that the chain is likely to last just as long as other mechanical parts inside the engine.
    So.....what difference do you think that it really makes to you; what practical difference, that is ???
     
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  15. bear15

    bear15 Member

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    Thanks for the kind words, Sam. To some of us, however, it makes a big difference if you drive over 60,000 miles a year under challenging conditions as chains do have there issues as well.(see post 9,561 in 60 days). That is why I started this post. However, the additional information is very helpful. I am not sure why you are not interested in the initial question, but please do not punish me for asking. I am just trying to add factual information to the literature on this new Prime forum-- sorry for the inconvenience and please forgive me.

    Cheers, Ed


     
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  16. bisco

    bisco cookie crumbler

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    don't take it personally ed, we're all under the same scrutiny.:)
     
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  17. DonDNH

    DonDNH Senior Member

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    If a timing chain does break, there will be much damage to both the crankshaft and camshaft gears that the chain connects. Both will probably have to be replaced. The possibility exists that the cam and the crank could also be damaged as well as the bearings on which they ride.:eek::(
     
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  18. Mendel Leisk

    Mendel Leisk Sidewalk Supervisor

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  19. Trollbait

    Trollbait It's a D&D thing

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    If a timing chain break is a concern, have it inspected regularly. Broken bits of metal getting tossed around are going to do other damage, that will likely make whether the engine is interference of not moot.
    Some parts are just a real PITA to work on or simply get too. Heard you actually have to lift the engine up some to reach the spark plugs on the 6 cylinder Outback.
     
  20. ChapmanF

    ChapmanF Senior Member

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    You could search the forums here for other things people have been told by Toyota service managers and senior tech guys about other subjects, and it might not leave you thinking that settles your question either.

    Your profile lists "other non-hybrid," so I take it you are asking this question while deciding whether to buy a Prime?

    So suppose the senior tech guy tells you "yup, it's an interference engine, just like folks were telling you on PriusChat." What's your next step? Would you buy a different vehicle?

    Or, suppose you get a senior tech guy who says, "don't worry, it's a non-interference engine, those PriusChat folks don't know what they're talking about." What's your next step then? Would you buy the Prime?

    -Chap
     
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