[Vwdiesel] differentiate between turbo block and NA

mark shepherd mark at shepher.fsnet.co.uk
Fri Jul 15 04:33:50 PDT 2011

Main reason for sticking a 3 hole gasket on is laziness and limited 'on shelf' stock, safe bet etc. If there were a benefit [there is no differrence between na and turbo compression ratios after 1980ishwhen engines went from 23.5:1 to 23:1] only a normally one hole would gain, with 2 holer half this gain.
If you have 11mm bolts then you have an early mech head, and bolts may rip out of block as they are too short IIRC. 
Cure by installing studs

  ----- Original Message ----- 
  From: j e 
  To: mark shepherd 
  Sent: Thursday, July 14, 2011 6:46 PM
  Subject: Re: [Vwdiesel] differentiate between turbo block and NA

  Ty Mark. a thicker headgasket is frequently employed on a NA engine to lower compression to make compatible with the extra boost brought on by the turbo. i was told VW had done that too..

  Gasket thickness has no relevance to turbo/na.  Thickness is determined by piston protrusion above block. This is determined by machining variance by the building engineer.
  All blocks beyond a certain age were 'turbo' compatable I believe. Engine codes MF, RA, SF, CY all turbo, but CY could be hydraulic or mechanical valve adjusters. Engine codes are scratched under the side water outlet of the head...


  ----- Original Message ----- From: "j e" <newdarkages at yahoo.com>
  To: <vwdiesel at vwfans.com>
  Sent: Thursday, July 14, 2011 4:49 AM
  Subject: [Vwdiesel] differentiate between turbo block and NA

  does anybody have the rabbit/jetta IDI turbo block casting numbers or is there another way to differentiate between turbo
  block and NA? Are there any other differences in the cylinder head/block besides a thicker head gasket and the piston

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