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4g91 Mivec inside.

Discussion in 'Car Modification' started by 4g15p, Mar 4, 2010.

  1. 4g15p

    4g15p Senior Member
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    Cheers..

    I have question with regards to the subject, as my engine is mivec but with 4g91 block.. the block already rebored to 81mm and installed with mivec piston.. and not to forget... added oil squitters.. everthing seems to be ok after the conversion.. power is ok.. mivec kick at 5.2 k rpm... after 6 months.. i've noticed power loss.. especially during hot weather driving.. mivec sometimes not working.. engine starts to pinging... even running with RON97..

    today, i sent workshop... after testing & troubleshooting.. they concluded that my engine block is getting hotter.. & that's the reason for power loss.. and intermittent mivec.. they said due to the block rebored to 2mm.. from 79 to 81 mm, the cylinder wall getting thinner which result to extra hot temperature... they said it's a normal problem for over rebored block..

    my question.. is it correct... is there other way to overcome the hot temperature issue.. or the block already spoil?..

    cheers..
     
  2. protonevo

    protonevo Senior Member
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    I would advice forget the 4G91 block because is really over bored. Take 4G92 DOHC OEM will last you for long time and save cost. Feel more kick get 4G93 doch block sure you will smile during 5k RPM ;> . I know this may cost you additional money. So for the time being just drive it as it is, when budget allow then you change it.
     
  3. har1th7

    har1th7 Senior Member
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    just 1 question? ru still using the stock radiator?
    Maybe time to change to larger @ full aluminum radiator ... and maybe with larger fan (volvo maybe)..
     
  4. 4g15p

    4g15p Senior Member
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    now i'm using standard lancer radiator, but double layer.. without coolant..
     
  5. boyzone

    boyzone Senior Member
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    If the block still ok, go for coolant and big cooling fan.
    Low temp thermostat, fan switch and oil cooler are the must for over bored block.
     
  6. kayour

    kayour Senior Member
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    2mm oversize can consider a serius play la...not reali recomended 4 daily car
    as u see from the temperature going higher easily...due to thinner cylinder wall and can cause pre ignition
    and...mivec intermiten also caused by hot lub oil-their viscocity change..
     
  7. 4g15p

    4g15p Senior Member
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    planning to upgrade 93 block, need to save some money coz it's not cheap nowdays..
     
  8. contreasjun27

    contreasjun27 Senior Member
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    there is few ways of improving this matter bro..
    1. try to get aluminium radiator as it is proven to ensure your engine gets cool down faster
    2. get a very big cooling fan, or those performace fan
    3. oil cooler kit is very important as well as it cools down ur oil temperature
    4. get a ventilated hood?
     
  9. xtremeleo

    xtremeleo Senior Member
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    improve cooling ie use a racing thermostat or mod urs to open earlier, get a more powerful rad fan, bigger rad is optional

    better yet, get a lube dat contains a lot of moly ie elf, total, or eneos. u may not require extra cooling if the lubrication is enough imo
     
  10. contreasjun27

    contreasjun27 Senior Member
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    where can find this racing thermostat?
     
  11. 4g15p

    4g15p Senior Member
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    now i'm using normail oil pan from 4g91, does aluminium oil pan a must for me?
     
  12. lonelylilpig

    lonelylilpig Senior Member
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    Re-bore is the dumbest idea of all . Just change the block will do.
     
  13. contreasjun27

    contreasjun27 Senior Member
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    well aluminium do distribute the heat faster so it is pretty good choice as well..
    how much is the aluminium oil pan selling now?

    ---------- Post added at 01:08 AM ---------- 6 hour anti-bump limit - Previous post was at 01:06 AM ----------

    dont say that.
    alot of ppl got no budget to rebore dude..
    so pls be considerate before you say such thing:thefinger:
     
  14. 4g15p

    4g15p Senior Member
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    lat time i've decided with rebore coz tired with the JPJ endorserment procedures...
     
  15. lonelylilpig

    lonelylilpig Senior Member
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    Bro, i'm more than considerate ....
    If u look in this way change a specific displacement block against rebore ; change block for few hundreds , one time job no extra job later on. Rebore, cost more or less than 200 , defects come out later on, remove engine , add in this and that ........

    Now u tell me which is more cost saving option...... Think about it . Play hard and smart !!
     

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