1.6TD Lifters - internal plunger height different than TDI lifters?

[Whitbread]

Hello, I just rebuilt my 91 1.6TD motor in my 81 rabbit after it blew a headgasket with only 436K on the clock. Rebuilt it with all new bearings, polished crank, new rings (only had .004" piston to wall clearance, tight enough for a beater shop truck), AAZ head gasket, and a set of raceware head studs. I run a TDI shop and since I work on 99% 96+ and newer TDI's, those are the lifters I had in stock. I was under the impression that all 8v vw engines used basically the same lifters, just changed a PN depending on 7 or 8mm valve stems. With the TDI lifters in my 1.6, I'm getting a crazy amount of valve tick. I removed the valve cover and all lifters can be rotated very easily with one finger while cam is on base circle. That tells me they're not remotely preloaded like a hydraulic lifter should be. I measured the height and OD of the TDI and IDI lifters real quick and they were identical, but didn't think to measure the plunger height before tossing them in the scrap barrel (which they're now at the very bottom of a 55 gal barrel that's overflowing). Does anyone know if they are in fact different? Or is my cam just that worn? Anyone have a stock base circle diameter measurement handy?

Thanks!


The truck it's in

 

[Whitbread]

Nobody has ever run into this before?

[libbydiesel]

AFAIK all the lifters are the same.  Oil pressure to the head is good?

[Whitbread]

As far as I know, there's plenty of oil up there when the valve cover is off. I'll hook up a pressure gauge to the port on the end of the head and see what it says. Don't know why it wouldn't be good, brand new AHU oil pump, new intermediate bearings, and new main/rod bearings.