Eurovan 4-cyl AHU TDI engine rebuild 101

It's been a good couple of weeks in the shop, catching our breath and enjoying the holidays a bit.  In the process we've been busy with a few things, namely diving into our next conversion: a 93 Eurovan T4 Weekender.  Here's the highlight reel:

 Prepping AHU block for 4-cyl EV R mount.  Three 6m bolt holes are drilled out to the appropriate VW sanctioned size.

Post- drilling 'mole hills'.

 Tapping bolt holes.

 OEM EV/T4 bolts threaded into new holes.

 4-cyl EV/T4 mount test fit for fitment.

 Now onto drilling the factory stepped 4-cyl EV oil dipstick tube hole in block.

Stepped hole complete.  Big shavings means sharp drill bit.  That's the way we roll.

 View from below through block.

 Short block engine rebuild parts.  Re-bushed rods, new ASV pistons, 0.50mm over, new rod/main brgs & bolts, ARP head studs, polished crank.

 TDI engine rebuild 101:
1) install oil squirters (w/loctite)
2) install block side main brgs (w/assembly lube)
3) lay crank
4) check radial clearance (w/plastigage)
5) install bearing caps (w/assembly lube)
6) install new TTY main cap bolts and torque to spec (48ft/lbs + 90*)
6.5) install new TTY crank bolt, lock with 3/8" extension placed strategically under crank throws torque to 68ft/lbs + a big 90* (w/loctite as per GW instructions, NOT oil as per VW!! This one is too important to ever come loose!)

 7) Install rods onto pistons, noting rod # and piston #s (1/2 or 3/4, w/ assembly lube on wrist pin), as well as keeping the raised "nub" always to the front/I-shaft side of the engine.







 **Shown for comparison/edification only: note the underside of the ASV piston on the R showing the additional oil galley(s) underneath the piston crown compared with the stock AHU piston on the L

8) Install pistons into cylinders (w/copious oil); careful attention to piston # and cyl. #, numbered 1, 2, 3, 4 L to R in this photo.

Ring compressor tool in use.

 **Shown for compariston: OEM 4-cyl EV/T4 oil pump on the R, Jetta TDI oil pump on the L.  Note the angle of approach and the depth of the pickup tube, corresponding with the deeper oil pan and angled forward installation of the engine in the T4.

 Another view of the difference, TDI on the L, T4 on the R.

 9) Oil pump fitted to engine (w/oil in gears and on mating surface, torqued to 18ft/lbs)

10) New 4-cyl EV/T4 oil pan installed w/oil pan bolts torqued to 10ft/lbs, and short block complete.