Replacing Pistons

  1. Regular Poster Joined: Feb 2012 Posts: 334
    #1
    Hi guys, thinking of fitting some low compression pistons - the standard ones are what, 78.5mm?

    So should I be looking at getting the block bored out by 0.5mm? And would this involve removing the engine?

    What would be the negatives if I didn't?

    Cheers
  2. West Midlands Joined: Dec 2007 West mids Posts: 23149 Supra,civic GL
    #2
    Why fit low comps?

    Yes youll need.to remove the engine if you want to bore/hone the block
    Id at least get a very light hone even if you retain the oe piston size but you can get different size pistons to get more capacity

    If you didnt and you try and fit 0.5mm oversized pistons they simply wont go in the block
  3. Regular Poster Joined: Feb 2012 Posts: 334
    #3
    Fitting low-comps as part of a turbo project

    Just considering which size to order, if I need to bore the block and the positives/negatives of that decision.

    If I didn't have them bored out, apart from a small amount of oil burnt, are there negatives?
  4. Regular Poster Joined: Feb 2012 Posts: 334
    #4
    Anyone shed any light on this?
  5. L-plater Joined: Mar 2007 Wakefield Posts: 54 Saxo VTS Turbo
    #5
    if the bores are good you could give them a light hone and fit standard size pistons but if they are worn slightly then they need to be bored

    Si
  6. Regular Poster Joined: Feb 2012 Posts: 334
    #6
    Cheers Si. Assuming that I'm having no issues at the moment, no excessive oil useage etc - wouldn't fitting the same sized pistons be fine?
  7. West Midlands Joined: Dec 2007 West mids Posts: 23149 Supra,civic GL
    #7
    Id still go for a very light hone even of there are no issues its just good practise to do and with how much of the motor need to come apart to fit new pistons itll be easier out the car so no effort to send it for a hone at that atage