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Author Topic: Water pump underdrive pulleys  (Read 7785 times)

May 16, 2004, 04:13:21 pm

fspGTD

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Water pump underdrive pulleys
« on: May 16, 2004, 04:13:21 pm »
Hey, just wondering if you guys have paid any attention to water pump pulley drive ratio on gas vs. diesel.  It seems that the diesels, especially the 1.6lTD, may have an overdriven water pump compared with gas motors due to their reduced redline, and also maybe compared to the earlier, 1.5l naturally aspirated diesels that seemed to have a peakier power curve vs the 1.6D's.  What have you guys noticed for water pump drive ratios on gas vs. diesel?  If there is an easy OEM pulley swap to underdrive my '84 1.6lTD's water pump, I would give it a try to try and pick up a little extra power a high RPM.  A complicating factor is that my Rabbit has power steering (funky dual-belt dual-pulley setup.)  If at all possible, one thing I'd like to maintain is the factory harmonic balancer, so that would limit my changes to the water pump pulleys only.

All the pulleys are hard to make sense of in the VW parts database, but I assembled them into a list which is below.  Too bad it doesn't list pulley diameter, offset, etc along with the part number.  Interesting to note that that there is no cross-over of pulleys, it seems, between gas engines and diesels.

TD crank pulleys (non-serpentine):
  068 105 243 / CY: Quantum ('82-'85)
  068 105 243 A / CY MF (up to '91/'92)
  068 105 243 H / MF 1V ('91/'92 on)

Water pump v-belt pulleys:
gas 30mm:
  049 121 031 / EN JF JH, NO AC and NO PS / RD
  055 121 031 C / EN JF with PS, (with or without AC)
  055 121 031 D / EN JF JH EH EJ FX, with AC
  026 121 031 / Jetta:JH /  PF RV GX MZ RD
  027 121 031 / PF RV JH, with AC / 9A
  027 121 028 / 9A, with PS / RD, with AC
diesel 30mm:
  068 121 031 F / CR JK CY with PS, (with or without AC)
  068 121 031 K / CR JK CY ME MF 1V
  068 121 031 L / ME MF, with PS ('85 TD)
  068 121 028 / MF 1V, with PS
gas 40mm:
  056 121 031 / gas: EN JF EH EJ FX EE, NO AC and NO PS
diesel 40mm:
  068 121 031 / diesel: CR CK CY (Vanagon: CS)

Water pump outside v-belt pulleys:
gas:
  027 121 031 A / PF RV 9A GX MZ RD JH with PS
diesel:
  068 121 031 N / ME MF with PS
  068 121 031 M / ME MF / with PS with AC

Also interesting that the gas power steering pulley is different than the diesel.

Can anyone on here help me make some sense of this mess?  :o

Thanks for any useful info...


Jake Russell
'81 VW Rabbit GTD Autocrosser 1.6lTD, SCCA FSP Class
Dieselicious Turbocharger Upgrade/Rebuild Kits

 

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