interference versus noninterference engine??

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

  1. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    163
    31
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    Does anyone know if the gas engine in the Prime is an interference or noninterference engine? I know a noninterference (free-running) engine will not be damaged if the timing belt breaks. I also know that the 2003 Toyota Highlander has a noninterference engine so when the timing belt broke at 150,000 miles or so no engine damaged occurred.
     
  2. Insirt

    Insirt Junior Member

    Joined:
    Nov 6, 2016
    50
    57
    0
    Location:
    South Carolina
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    I guess it's non-interference but I'm not sure if it's applicable since the Prime and all Prii don't have a timing belt or chain (or any real transmission just a torque converter, unrelated to timing).

    If you're worried about powertrain lifespan don't be; it lasts longer than almost all vehicles.

    EDIT: My mistake all Prii including the Prime have a timing chain for the ICE. See other better informed responses...

    Posted via the PriusChat mobile app.
     
    #2 Insirt, Jun 3, 2017
    Last edited: Jun 3, 2017
  3. john1701a

    john1701a Prius Guru

    Joined:
    Jan 6, 2004
    11,295
    4,122
    52
    Location:
    Minnesota
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Prius uses a chain instead. So, concerns related to a belt don't apply.
     
    dalcon95 likes this.
  4. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    163
    31
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    This is helpful information. I did not know that all Prii (and the Prime) do not have a timing belt or chain. My son has a 2016 Prius C so I am safe to assume that is true for his car also? Many thanks.
     
  5. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    163
    31
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    John- can you clarify please. I am confused by the post #2 regarding no chain. Thanks

    john1701aPrius Guru
    Prius uses a chain instead. So, concerns related to a belt don't apply.
     
  6. dalcon95

    dalcon95 Senior Member

    Joined:
    Oct 6, 2011
    511
    643
    2
    Location:
    Easley, South Carolina
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    All Prius years and model variations have timing chain.

    #1 in Easley,SC
     
    jerrymildred likes this.
  7. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    78,056
    32,959
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    there is a timing chain under a cover on the engine. i don't recall ever hearing about one breaking, but i suppose they stretch a bit after very high mileage.
    a bigger issue has been a leaking cover on some models, which requires a lot of disassembly to repair.
     
    #7 bisco, Jun 3, 2017
    Last edited: Jun 3, 2017
    dalcon95 and Raytheeagle like this.
  8. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    7,761
    10,347
    0
    Location:
    Bay Area, CA
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Here are several pics of the timing chain and the 1.8L engine internals on the Gen3 motor:

    Blown Head gasket [email protected]

    Peruse at your leisure this thread as it has good documentation and discussion around the 1.8L engine;).

    Enjoy the light weekend reading (y).
     
  9. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    163
    31
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    Awesome pics and information- many thanks!! However, I think this brings us back to my question. Does anyone know if the gas engine in the Prime is an interference or noninterference engine? I know a noninterference (free-running) engine will not be damaged if the timing belt or chain breaks.

    wrote before:
    Here are several pics of the timing chain and the 1.8L engine internals on the Gen3 motor:

    Blown Head gasket [email protected]

    Peruse at your leisure this thread as it has good documentation and discussion around the 1.8L engine;).

    Enjoy the light weekend reading (y).
     
  10. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    163
    31
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    Hi Bisco- What is a "leaking cover" and at what miles have we been seeing this?
    Wrote before:
    a bigger issue has been a leaking cover on some models, which requires a lot of disassembly to repair.
     
  11. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    7,761
    10,347
    0
    Location:
    Bay Area, CA
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Very few reported claims of the timing chain breaking or failing. There have been many Prii that have eclipsed 300 k miles without issue with the chain. In a Prime, the engine should be running less (depending on your use) so less risk of damage.

    If the chain were to fail, I would assume some damage would occur. But in the 20+ years of driving I have logged in various different makes and models, I have not dealt with that issue.
     
    bisco and dalcon95 like this.
  12. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    7,761
    10,347
    0
    Location:
    Bay Area, CA
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Here's a recent thread on the topic with a link to another thread on the same topic:

    Timing cover leak

    More light weekend reading (y).
     
    bisco likes this.
  13. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    163
    31
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    How can we check, just for interest, if it is a noninterference (free-running) engine and will not likely to be damaged if the timing belt or chain breaks, etc.

     
  14. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    163
    31
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    Interesting . . . many thanks.
     
    Raytheeagle likes this.
  15. dalcon95

    dalcon95 Senior Member

    Joined:
    Oct 6, 2011
    511
    643
    2
    Location:
    Easley, South Carolina
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    I think most new engines are interfering because of close tolerances and high compression.

    #1 in Easley,SC
     
    bisco and Raytheeagle like this.
  16. bear15

    bear15 Member

    Joined:
    Jan 28, 2006
    163
    31
    0
    Location:
    Suburban Chicago
    Vehicle:
    2015 Prius
    Model:
    Three
    I also know that the 2003 Toyota Highlander (and several other Toyota engines) has a noninterference engine so when the timing belt broke at 150,000 miles or so no engine damaged occurred.

     
    dalcon95 likes this.
  17. Sam Spade

    Sam Spade Senior Member

    Joined:
    Dec 3, 2016
    2,036
    983
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    It is still a valid question but your use of the term "free running" sounds like you don't really know what the concern IS.

    With over head valves OHV, if the valves are still full open when the piston reaches top dead center TDC, the valves can hit the top of the piston unless the clearances are designed to prevent that.

    Anything that throws the valve timing WAY off can cause the collision in an "interference" design.
     
    dalcon95 likes this.
  18. dalcon95

    dalcon95 Senior Member

    Joined:
    Oct 6, 2011
    511
    643
    2
    Location:
    Easley, South Carolina
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
  19. Mendel Leisk

    Mendel Leisk Sidewalk Supervisor

    Joined:
    Oct 17, 2010
    32,716
    21,702
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Just for novices not conversant with the terminology: saying an engine is "interference" means if the camshaft rotations are not properly synchronized with the crankshaft, that both are allowed to turn freely and independently (due to absence/breakage/misalignment of timing belt or chain between the two shafts), then it is possible for the pistons to hit the valves.
     
    Mark McIntyre, Nic Steussy and Insirt like this.
  20. LouG123

    LouG123 Member

    Joined:
    Feb 26, 2016
    47
    46
    0
    Location:
    Vernon Hills, IL
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    Gates is the primary supplier of automotive belts in the US. They used to have a means of searching for a specific car to tell you whether or not it had a timing belt, and if so if it was an interference engine, but I can't tell from my phone. You may want to search here:

    Timing Belt System Products | Gates Corporation
     
Loading...