Rena 2.0 TLC - PeachParts Mercedes-Benz Forum

Alec300SD · #1 01-04-2015, 01:46 AM

Faithful “Rena 2.0” recently got some much deserved TLC.

Firstly, she got a new Interstate MT5-49/H8 battery. It is an AGM (Absorbed Glass Mat), or spill proof, battery with 900 CCA and a 30 month warranty. The last battery (not AGM) bit the dust this winter and refused to hold a charge for more than 4 or 5 days, probably because it had become sulfated. It was an old Diehard battery with 850 CCA, the sticker was from 09/2009 and so it did give a pretty long service life.

The flaky tachometer amplifier was replaced with a good used unit. No more intermittent loss of the tachometer gauge function!

She also had a cleaning of the IP (injection pump) with two cans of Lubro Moly Diesel Purge. I changed the primary and secondary fuel filters and installed a Viton 2.5 mm X 10mm ID hollow bolt o-ring (I sometimes use biodiesel, B-20 to B-100).

It had been almost 12,000 miles and 12 months since the last valve adjustment. So the valves were also adjusted with the engine cold. A few valves were tight (2E, 3I, 4I, 4E and 5E were tight), and the intake valve on the first cylinder was very loose.

Compression was also checked on the engine cold and it is not too bad overall for a rescued beater motor (‘Rena’ - a 1982 300 SD). The readings were: Cylinder 1 - 300 psi, cylinder 2 - 310 psi, cylinder 3 - 370 psi, cylinder 4 - 355 psi and cylinder 5 - 330 psi. Previously on 7/7/2013 the readings were: Cylinder 1 - 325 psi, cylinder 2 - 325 psi, cylinder 3 - 360 psi, cylinder 4 - 305 psi, and cylinder 5 - 305 psi.

Greazzer rebuilt the old injectors that came out of “Desert Rose” with the new Monark nozzles I supplied. One injector body would not seal so he supplied a substitute with a longer nozzle body holder. He also sent me one of his rebuilt Performance OFVs (Over Flow Valve). The OFV is actually a specially modified hollow bolt on the hard “clear” (actually brown by now, on most OM617s) Teclan return fuel line on the engine side of the IP. The other end of this hard line is on top of the fuel filter assembly and two other hoses are also attached to it (the cigar hose/return line to the fuel tank and the small diameter fuel injector return line that attaches to the first injector).

The old injectors looked pretty good, except for cylinder one’s injector which was very oily and black. Four of the new rebuilt injectors are in, as is the Performance OFV.(Unfortunately, one of the rebuilt injectors leaked from the base of the return nipple and is being replaced). The car ran much better with the 5 rebuilt injectors (and old OFV), even though one rebuilt injector had a slow drip/leak. There was an even greater improvement in power and performance especially in transient response at 60+ mph using the 4 new and 1 old injector along with the new Performance OFV. She is still smoky on cold startup and on heavy acceleration; it appears to be from un-burnt fuel.

Once the last injector is rebuilt again (same new Monark nozzle in a better core) and installed along with the hard line clamps (and the glow plugs are pulled, tested and carbon reamed out of the glow plug holes) the plan is to run her hard with regular “Italian tune-ups” for a few months and then recheck valve clearances and compression (both dry and wet). Eventually, “Rena 2.0” will probably need to see a professional mechanic familiar with OM617s for additional diagnostic work. For now she is a dependable daily driver with a little more “get up and go” than before.

Anyone wanting an inexpensive and easy 5 minute upgrade to performance in an OM617?
I highly recommend Greazzer's Performance OPV. "Desert Rose" is getting this upgrade as well; the order has already been placed.

Alec300SD · #2 01-12-2015, 04:17 AM

Rena 2.0 got an oil change with about 7 quarts of Chevron Delo 400LE 15W-40, a new Mann oil filter, 2 new o-rings on the shaft of the oil canister lid, new large sealing o-ring for the oil canister lid and a new copper crush washer for the oil drain plug.

At the yard, I found a suitable early style DS lower body molding for the rear wheel arch. I cleaned it up and installed it in place. The old one was lost on the freeway a while back when the DS rear tire self-destructed.

The DS rear light assembly had a cracked side marker lens and the plastic lenses on both rear light assemblies were very dark from age. A few months ago I purchased newer assemblies from a 1990's gasser and finally got around to installing them. The rubber seals on the newer units looked very good overall, just a little drying of the rubber on the top edges of the seals. I cleaned the bumper, rear light assemblies and the rear sheetmetal with 303 Cleaner. It worked very well to remove the crusted bits of the old seals stuck to the sheetmetal and easily took off the road tar on the rear bumper. I also used the 303 Protectant liberally on the old rubber seals and the plastic rear lenses. I never knew about the 303 series of products until reading about them here on the forum. I found them at my local West Marine boating supply store. After a half hour soak, I removed the excess and installed the new (used) rear light assemblies.

Rena 2.0 runs and looks a little better from the recent TLC. Even with the headlights off, she is more visible with the newer reflectors in place in the rear.