replacing my mk2 bottom end with a mk1 bottom end - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• replacing my mk2 bottom end with a mk1 bottom end by gtidiesel1.6 on 14 Apr, 2010 16:46
• So a few weeks ago my bottom end went on my 87 NA golf, the wife drove it to the very last drop of oil, now i have a chance to get a free bottom end from a mk1 jetta, that was running and driving daily until the timing belt broke. Everything was fine and dandy and i was excited to get my car back on the road until i remembered that mk1's are solid lifter heads and mk2's are hydro. I haven't picked up the bottom end yet and i havent checked if mine is hydro or solid(car is 80kms away). worst case scenario what needs to be done to make my mk2 head work on the mk1 block? i heard all sorts of things about different size heads and head bolts but its way to confusing.
• #1 by rs899 on 15 Apr, 2010 04:03
• It depends on how early the Mk1 block is as to whether it has 11 or 12mm bolt holes.  I think the cutoff was in the middle of 1981.  Your head will be 12mm and if it is hydraulic, will have an extra oil return hole that will need to be plugged.  You should be able to get it to work, but you may have some things to do.
  
  Rick
• #2 by gtidiesel1.6 on 15 Apr, 2010 06:02
• the mk1 engine is in a mk1 jetta, id say its a 83'ish. whats the difference between the 11 and 12mm bolt heads?
• #3 by 8v-of-fury on 15 Apr, 2010 06:05
• one is 11mm and one is 12mm
  
  they are a different size bolt and threaded hole all together. The 83 should be a 12mm Hydraulic. Will it come with a head? you can make your hydraulic head work as mentioned. You will need to block off an oil return in the head however.
• #4 by rs899 on 15 Apr, 2010 07:06
• I think 8v meant to say the 83 bottom end will be for solid (mechanical ) lifters, but you can block off the one return hole on your (probably) hydraulic head and get it to work.  It should be 12mm head bolts so not too big of a deal.
  
  Rick
• #5 by 8v-of-fury on 15 Apr, 2010 08:25
• my bad, yes i did thanks.
• #6 by theman53 on 15 Apr, 2010 15:26
• I bet a nice 3/8 or 1/4 npt socket head pipe plug would work to block off the extra oil passage. If you got it to seal real good with teflon tape or sealant of some kind you could pull the plug if you ever needed to go back to hydro 
• #7 by gtidiesel1.6 on 16 Apr, 2010 01:04
• So if i were to run my hydro head on the solid lifter block i would have to block off the oil and coolant drain?
  
  I think im just gonna keep an eye out for hydro block then and keep things simple