1.9 aaz head on 1.7 na block - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• 1.9 aaz head on 1.7 na block by the caveman on 31 Jan, 2008 05:58
• I've decided on not dropping in a TDI into my 1990 transporter but am collecting parts to turbo/intercool it [ thanks syncroserge]. Am i to understand a 1.9l head will fit onto a 1.6/1.7 l block. I read somewhere the advantage is for the better breathing of the 1.9. Is there a thread some where for this?
• #1 by jimfoo on 31 Jan, 2008 07:24
• I know nothing about a 1.7, but if it is the same as a 1.6, then yes it will fit. It lowers the compression and makes cold starting harder though it might not be as bad on a 1.7 due to the greater volume. They use 12 mm bolts/studs.
• #2 by the caveman on 31 Jan, 2008 10:34
• how much does it compression ? can it be adjusted enough with head gasket thickness if mine oem one was 3 hole?
  Maybe i can weld or solder on some material to the top of the pistons :wink:
• #3 by MJF on 31 Jan, 2008 10:42
• 1,7 has mech block, so installing 1,9 hydraulic head is a bit more difficult. You´ll need to block the other oil return hole from head.
• #4 by the caveman on 31 Jan, 2008 11:16
• the head on there now is hydralic. it's a 1990 and im sure vw stopped all mech head production by 88.
• #5 by jimfoo on 31 Jan, 2008 11:30
• Then it would be an easy swap. I don't know how the compression would change, but you can't raise it by going to a thinner head gasket as that is a critical dimension needed to avoid the piston hitting things. You could possibly fill in the reliefs on the pistons, but that would probably hurt swirl and power.
• #6 by mdonau on 31 Jan, 2008 12:19
• hi,
  
  all diesel-engines in the T3-transporter had mech-heads. (CS, JX, KY)
  all other VW/Audi-Engines were hydraulic from the middle  of 1985
  
  but: the KY is a low longblock
  
  means: 79,5 bore with 1,6 con-rods and crank
  with some mods a hydraulic head can be mounted..
  just open some holes in the Block...
  
  greets, michael
• #7 by the caveman on 31 Jan, 2008 15:49
• okay MJF and mdonau you are right. I haven't taken off the valve cover yet and there aren't any stickers about adjustment specs under the hood.
  i guess i will have to get a 1.6 hydralic block, head and 1.9 head to measure the difference. maybe i'll just stick to the 1.7 head instead.Do you guys in europe which 1.7 blocks have the piston cooler jets?
• #8 by RabbitJockey on 31 Jan, 2008 18:02
• from what i have read the cold starting isn't really that bad, malone really tried to make a point of that with his hybrid.  and he had even lower compression than just a regular head swap