SuperTruck: Firing up the Diesel

by Ben N on July 16, 2013

A few days ago, my friend Steve stopped over to help lend a hand on the DIY Open Source Plug-In Hybrid “SUPERTRUCK” project.

At the heart of the project are two things, a diesel engine, and a big forklift motor. And while I’ve learned a thing or two about DC motors the last few years, I still know next to nothing about diesels! That’s why I was glad that Steve could lend a hand.

We had the engine on a furniture dolly and dragged it out of the corner to work on it. It’s been sitting around for a few YEARS now in total since it was ever in a car. However, the engine DID run when I pulled it out of the Mercedes 240D.

To get started, we needed to reinstall the flywheel and starter. Sounds easy, right? Well, it turns out that both were slightly challenging right off the batt. The length of bolts needed for a manual flywheel instead of the automatic one are different. So, we had to evenly space out the bolts with some thick washers. Not the best approach for the long-run, but we figured it would be fine for just getting the engine to turn over.

The starter had a similar issue. The main bolts that hold it to the engine actually mount the front of the starter through the bell housing and THEN to the engine. Without the bell housing in place, the bolts are far too long, and can’t tighten down. While I no longer have the automatic transmission, I DID keep the bell housing from it. Once the flywheel was on, we capped it with the bell, and mounted the starter.

The oil pump had two loose hoses. Something would have to be done with those before starting the engine, otherwise oil would just be shooting everywhere. I dug up the original radiator, which had the oil-cooler connected to the side of it. We took off the oil cooler and plumbed it to the engine. Looking at the cooling system, we saw that the water pump was  shot. We pulled it off. Sure enough the bearings on the impeller were seized up. Time to order a new one!

We rolled the engine out of the garage to the driveway to prepare to fire it up. What else do we need? FUEL! That’s right, some nice fresh diesel fuel would be great. I repurposed an old 2-gallon gasoline can into my fuel tank. (I know, I know, it’s NOT Yellow! But I did write DIESEL on it!) A quick trip to the station netted us eight bucks of diesel. It was pretty funny to see a Geo Metro parked at the big diesel pump though!

I had some assorted tubing and a small, 12V fuel pump, so we rigged t hose up to get fuel up to the engine. The next big trick was bleeding the fuel injectors. This was something new to me. Unlike a gas engine, the diesel fuel is a thick oil, which can be blocked by air bubbles. It’s similar to having to bleed air from brake lines, only in this case, instead of the car not stopping, the engine wouldn’t run.

Bleeding the fuel injectors was actually pretty easy. Just needed to loosen them and cycle the engine until fuel started coming out instead of air.

Now, it was time to actually fire up the engine. With jack stands under the engine mounts, the 12V battery wired to the starter, and the glow plugged heated for a few moments, now was the MOMENT OF TRUTH! Steve hit the starter remote and…… (drum-roll please!) it started right up!

WOW! It actually ran! Sounded pretty good too! It wasn’t as loud as I thought it would be either, considering that there was no air filter or exhaust installed!

We just ran it briefly, as there was no cooling system installed. We did find that it leaked a little bit of oil through the water pump bolt holes, because the pump wasn’t in place. It also looked like there was a little bit of a fuel leak from the manual priming pump. That might need to get rebuilt. Other than that, it looked pretty good!

So, time to order that water pump, find some shorter bolts, and get on to designing a plate to mount the Mercedes 240D engine to the Chevy S10 Manual Transmission!

’til next time,
-Ben

{ 1 comment… read it below or add one }

1 JD July 28, 2013 at 9:06 am

Interesting project, keep us up to date!

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