Why would you put a 1.5 head on a 1.6 block? - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Why would you put a 1.5 head on a 1.6 block? by ventureforth on 13 Aug, 2010 02:40
• Is there and advantage?  I saw this http://www.vwdieselparts.com/1.5-1.6.htm  and was curious what the incentive is...
• #1 by rs899 on 13 Aug, 2010 04:56
• As far as I know, only because you happen to already have one and want to use it.  Perhaps the cam is different?  Tyler can chime in here....
• #2 by theman53 on 13 Aug, 2010 05:31
• Yeah I think it is more of a thing were the owner can't find a mechanical 1.6 head and has a 1.5 head.
• #3 by Baron VonZeppelin on 13 Aug, 2010 08:19
• Same as what they said.
  
  It also raises comp. ratio a bit too.
  Like 23:1 isn't enough already ...
• #4 by 84tdrabbit on 13 Aug, 2010 09:53
• 25.5:1 IIRC
• #5 by ventureforth on 13 Aug, 2010 13:51
• Okay, that's what I figured.  I read some posts about higher CR and larger swirl chambers, but figured it was only a "well, I got a 1.5 lying around so it's free" sort of deal.  I actually do have a 1.5 lying around and need to do a HG soon, so if the 1.5 was an improvement, I would have swapped it on.
• #6 by 84tdrabbit on 14 Aug, 2010 11:45
• the 1.5 has considerably smaller swirl chambers...
  
  how would BIGGER swirl chambers make MORE compression?
  
  and its not a direct bolt on swap for the head..
  
  you kinda need to make an adapter bushing for the front oil return..
• #7 by RabbitJockey on 14 Aug, 2010 15:08
• i thought 1.5s and tds had the same pre cups?