Converting a gasoline engine to diesel power. (Page 2 of 2)

OM606 parts are goddamn impossible to find. >_<

615 parts are gonna be rare as hen's teeth in the US, I don't think the 200D or 220D ever made it over here officially, and they'd be collector's items if you ever found one.
OM617, 601, 603, and 606 are the only ones you're likely to find parts for from anyone but the dealer, and MBZ prices on engine hard parts are hard to get your mind around. $900 for a set of rings for a 606.

It WAS! And what's better, it had head casting problems and overheated if someone spit on the sidewalk (turns out putting a thermal reactor right next to the head on top of a turbo is a bad idea?), so they're not that hard to find in ratty condition.

Pistons'll be fine, tho.

Sleeving cylinders is $100/hole where I'm at.  Rods, if you can find something in the length you need with a smaller journal, you can simply have the crank rod journals ground down, including possibly offset grinding to get your compression height, maybe.  This would be $$ too, and shops that can do that are pretty scarce from what I've seen.  If that rod you need is something in the 6.00-6.400 range, NASCAR has all sorts of weird length super premium  rods on ebay with Honda(1.88) journals for Lemons level money.  S/F.....Ken M

You need to go old school and start the motor on gas then switch over to diesel after it warms up a little...

For example:  https://www.youtube.com/watch?v=7UNdjbsMwI4

Yanmar has some diesels with bores in that range.  3TNV88C has 88mm bore, 90mm stroke, 3 cylinders for 1.64L displacement.  Uncertain about parts availability.  Kohler also does small diesels with pistons in this size range.  There's a team in SCCA CSR running 2cycle Kohler engines and I believe they have some factory support, so you might find some help from Kohler if you can get in contact with the right people.  Kohler's online service manuals show the pistons look like normal 3 ring automotive flat top jobs, so perhaps diesel specific pistons may be unneeded.  S/F....Ken M

One thing that is very common in diesels is piston oil sprayers.  IIRC, there was a nifty technique for machining a conrod to make it throw oil onto the bottom of the piston, I recall it was common on Porsche motors.  That might be worth looking into as well.  S/F....Ken M

http://www.shoptalkforums.com/viewtopic … p;start=30

pg 3 halfway down, there's a picture of what I'm talking about.  Volkswagon, Porsche, same difference, lol.

All I can offer is something with an 87.5mm bore size, available in Europe, but it has wacky cred:

How about an diesel engine designed by Isuzu, bought by GM, and put into Saab 9-5s (and Renault Espaces for even more wackiness):

http://en.wikipedia.org/wiki/DMAX_V6_engine

The problem is the original pistons are tall, measured from the Pin Center to the top of the piston 44.83 mm. Modern pistons are lighter (better for high rev-ing engines) and defacto shorter. For example Nissan VG30 (pathfinder 6 Cyl 3.0) pistons of 87mm stock are 32mm height (c-t) with 9 cc of dish. So to make up for the 13mm of height difference you need a longer connecting rod.

Stock 225 cu in rods are 170.18mm center to center
Stock 198 rods are 177.97 mm c-c. 8mm of difference, raises the piston and the CR
Nissan KA24 stock rods are 165mm C-c and they are some of the longest of the Nissan con rods I know of. The LD28 rods are only ~139mm long

The Sealed Power pistons for that range of bore (87.5mm up to 88mm) which are talked about for the long rod slant six are all 39.929mm height. Using the 198 conn rod, stock 225 crank and bored block gets you to the 12.7 static CR range. BUT the piston hits the head (piston extends out of the block by .8433mm). So you have to mill the piston. the Sealed power pistons are ~$100 for 4 (they are for the dodge 2.2l turbo). So you buy 1 set plus 2.

The solution to getting the Higher CR for a slant six diesel is to mill the head. And use the 198 con rods with some of those sealed power or Clevite pistons, and mill the tops off by ~.9mm.

Running my spreadsheet, with the Clevite TC2912, if you reduce the size of the head chamber from 54cc to 26 cc, you'll get 18.54 Static CR in my long rod engine. 15.95 dynamic CR with the Big Delta cam that was in there. With a stock cam, the  dynamic CR should go up a bit. the Clevite TC2912 are ~$30 each.

Too bad the long rod I built is in the JY, it had the 198 rods and sealed power pistons, and ran, all you would need to to is mill a head.
http://row52.com/Vehicle/Index/VH23C2B292839

Man, this thought is killing me.  Keep in mind I am a diesel mechanic, but not a diesel hot rodder.  These are basically opinions based on 22 years in the business tearing down and rebuilding engines.  My biggest issue would be the injectors.  If you use the older pop style injectors, you will need a higher compression ratio.  Otherwise the spray pattern may burn a hole in a piston.  Also, the older engine like the one in the Chevette, are idi, so injector placement and the combustion chamber relationship are critical.  The newer common rail injectors would work with a lower compression ratio, but that's gonna take some impressive electronic work as well as a high pressure oil pump to fire the injectors. 
     Pistons would be easy enuff, take an old one to a machine shop and have them make them from a solid billet of a high quality material.  That's what I'm working on doing for the Chevette.  As for a head gasket, again, take a stock one to a machine shop, and have one made from copper.  They can make it in any thickness to adjust compression ratio.