What is the difference between the two? Is it pretty much the same as the difference between the OM617 NA vs the OM617 Turbo with the oil sprayers? I have updated my ideas on what car I want to get and I am now looking at the 190D, but obviously the turbo was only made in 1987, and I don't know how many manual transmission ones are out there so you know the rest (I think).

AFAIK none of the US turbos came with MT. You'll have to roll your own.

The turbo IP is different as are the turbo injectors and prechambers. You can fit the turbo IP to a NA block but you can't fit turbo injectors without turbo prechambers. Turbo prechambers won't fit a NA head. If the 602 is anything like the 603, you can modify NA prechambers to fit a turbo head. I don't know about the more relevant other way around. You might be able to fit 603 turbo injectors in 602 NA prechambers as a quicker fix.

Note, what I describe as turbo injectors and prechambers is more accurately a change in design. The US spec '87 turbo 602 has the later style inclined injectors which come with corresponding prechambers. Later as in introduced in the 603 in the '90 model year. IIRC, US spec NA 190Ds continued with vertical injectors through the '89 model year.

Sixto
87 300D

Are the Pistons Different?


Trust me on this one,
Going to "Forced Air" on that N.A. OM602 (Safely) will be prohibitively Expensive.

almost be Cheaper to get a ReMan 602.962 from Noell's or Metric.

__________________
'84 300SD sold
124.128

They might be different for compression and oil cooling but the valve and prechamber reliefs should be the same.

Sixto
87 300D

Differences between OM602 NA and OM602 Turbo, according to FSM (most differences also apply to OM603):

1. Turbo head is "reinforced at the water jacket due to higher combustion pressures."
2. Turbo head prechamber bore is 15 mm, NA is 14 mm.
3. Original NA head gasket had normal sheet steel reinforcing around the combustion chambers (Turbo used stainless steel). However, all replacement gaskets are SS.
4. Turbo pistons have larger wrist pins (which presumably means different con rods), an annular oil channel for improved cooling, a recess on the piston skirt for the oil spray nozzle, a larger (18 mm vs 17 mm) prechamber recess in the piston crown, and possibly other differences depending on date of manufacture; FSM is not entirely clear.
5. Turbo engines have oil spray nozzles for improved piston cooling. Note: FSM section 18-045 says NA engine also have oil spray nozzles; this seems to contradict section 03-317.
6. The blocks may be different. I don't know if all 602 blocks have holes for turbo oil feed and drain, with the NA blocks plugged, or if the NA blocks don't even have those holes drilled.
7. FSM could be read as saying that NA 602 engines without EGR do not have oil coolers. (This may not be applicable to cars sold in the USA.)
8. Turbo engines have sodium-filled exhaust valves with chrome-plates stems and ground valve edges.

And probably more that I missed. Not all of these are critical, I suppose. YMMV.

Source: "Service Manual/Diesel Engines 602, 603," İM-B North America 1991, part number LZ S-2517-091.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Thanks... Looks like it a tranny or engine swap will have to do, not just adding a turbo

Does anyone have any idea how many 2.5 Turbos were in the US?

I'd think quite a few with the late W124s.

Did any US spec 60x engines have an EGR cooler?

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.