Chevy & GMC Vans

doyoulikeithere wrote:The custom Jobs are always an adventure eh?
Glad to hear your getting it figured out...

Yeah, I have been in contact with the kit manufacturer, and he basically said email him info when I figure it out, its never been used for a T5. The custom makes it fun though

Update-
round 4 a success!

Removed the transmission a 3rd time and the problem was immediately clear. You can see here the splines were pressing into the bearing, and actually cut a groove during my last super short test-



fortunately I had an extra pilot bushing I could modify, so I removed a total of 8mm from the bushing depth, 3mm to compensate for the ring spacer on the back side, and 5mm to clear the spline and give me a bit of a safety gap.

here is the cooked one next to the modified bushing. Ironically the final depth for the cut bushing is the same as the stock mercedes pilot bearing, 11mm.



here is the difference in depth in the pilot bearing adapter piece, formerly the end of the original bearing was flush with the end of the adapter-



and installed-




so reassembled everything and im in business! Im solving another large oil leak before I can go on a decent test drive, but it goes into all gears smoothly and engages well!

So update-

I finally drove this thing and its pretty interesting. I would say it takes some getting used to, but initially a little sluggish, but there is a learning curve like a 240 sedan, and I was zipping around decently once I found the right feel for the throttle. I instantly loved it, though I think I might want a better rear end ratio for later. Maybe a 4.10 ratio instead of 3.7. I only got up to 3rd gear, but the transmission feels pretty good, each ratio a bit shorter than the stock MB.

Wont do a highway test until I have all my gauges, and I still have big leak issues related to my remote oil filter plate. I have to take that off and repair it. Just looks like things arent threaded down tight enough, so might be able to do on the motor

here is a short video of the engine from the inside, unfortunately I was plagued by some traffic
http://www.youtube.com/watch?v=d-58YU9Q ... e=youtu.be

so I have a notion on the sluggish first gear-

I had thought on my RPO code for the van that i had a 3.73 diff, but after the test drive and sluggish first gear, I just went and verified at the axle tube and I actually have a FAS: 7.5", 3.23 open diff (thanks to doyoulikeithere's useful table post in drivetrain), which is way too low. The engine was originally mated with a 3.69 diff in the stock application, so im thinking a 3.73 would have been perfect, but a 4.10 would give me some nice low end torque for the heavier square body.

The manual trans ratios in the T5 im using are trans code 1352-201 which has really close gear ratios to the stock NA diesel gearboxes-

1-4.03
2-2.37
3-1.49
4-1.00
5-0.86
R-3.76

stock example MB trans gear ratios were-
1-3.90
2-2.30
3-1.41
4-1.00
R-3.66

the only ratios that are heavily off are the diff, 3.23 GM vs 3.69 MB.

If i convert to a 4.10 by swapping the ring and pinion, that should solve some of my sluggishness. If feels sort of if you are taking off in second for first gear as a comparison.

so heres what im doing about the battery. Turns out there is not enough room for the big mercedes diesel size battery to sit behind the passenger seat and still have room for the exhaust, so I had to move it to the other side of the driveshaft, even then it was a bit snug.

here is where the battery will live-



Here is the battery cage, I went a little overboard on the construction of this, on the left side in the pic there is a reinforced armor plate just in case there is a driveshaft issue. It should be able to take a major hit and be fine.
basically its just a stock MB battery tray in an angle iron structure-
The weight of this thing with the battery included might necessitate an inner piece to sandwich the floor instead of hanging from it




The plan is to predrill holes around this for splash shields and make those out of plastic sheet later on. I want to get it in and see if that makes sense.

here it is installed-



battery is a tiny bit snug getting down in there, but fine if its on a slight angle



armor plate next to driveshaft, pretty close, about 1.5 inchs-



this contraption takes up a lot of the available space in this area, but I should still be able to get the larger fuel tank in if I decide I want that

The larger fuel tank is longer at the aft end, not the fwd end, so you should be fine...

great! thanks for the info

couple updates-

so ive been tinkering around with power steering on this thing for a bit, and had gone so far as adapting a GM pump to a MB pulley. The GM pump sits low on the driver side and it could have worked If I could line the pulley up properly
stock GM



GM pump with MB pulley-



Unfortunately this is pretty hard to do properly, and ultimately decided I was reinventing the wheel, and put the MB power steering pump back on and adapted a high pressure line to it-



Line goes up and over to swing behind, I may redo this later, not really satisfied with the routing of this line-



However, power steering is all hooked up and its really nice to have that back, this thing has such a nice turning radius, it was a pleasure to start whipping it around with the power steering finally working.

Also, welded up exhaust, all I ended up doing is having a piece made with a little flex joint that ran back to the stock muffler and it was done. Used the opportunity to fix some rattling mounts that plagued this thing when I was using it with the gas motor. I still need to get in there and build a support bracket for the downpipe off I think the bell housing. Its a solid exhaust, but I would feel more comfortable with less potential stress on the turbo flange.




After that installed an aftermarket oil pressure and temp gauge, and I was ready for a day of test/use finally!
Puttered around for a few hours doing errands, where it did fine, took it out on the highway and 5th is really a hopeful gear. cruises along nicely in 4th, but 5th you really need a perfect flat to pull. I think this should improve when I get around to swapping the ring and pinion though, at least a little bit.

So far very pleased, sluggish in first takes getting used to, but I might be able to improve that by getting a new throttle cable or adapting some other style cable that is less sticky.

still need to-

-wire up charging system (priority)
-wire up glow plugs (priority)
-figure out shutting off by key Popping the clutch in first to kill it is effective, but hard on stuff.

so mileage and test update-

Yesterday I needed to take a fridge down to a rental property in southern CT from RI. I was excited as this was an ideal test run and shake down cruise.

I went first to a diesel station, and filled to the brim, then drove down to the property, completed the job, and drove back to the same diesel station, same pump, and filled to the brim.
On the way down I did all highway, and the way back I came cross country through hills and two lane back roads. The objective was to see how it performed on both.
I then later went into google maps and duplicated my route to get accurate mileage.
The trip down I traveled 157 miles, and the way back 141 miles for a total of 298 miles. When i filled up I had used 10.14 gallons of diesel, which is an astonishing 29.4 mpg for this thing in its first real trip! The best I had ever done before was 23 mpg, but more typically with the 4.3 the mileage was 18-21mpg. If I had done all highway, it might have broken 30mpg.

This represents a high water mark and I do not believe its sustainable, as the gearing is just not dialed in and its not super easy to drive, too much top end gearing, not enough granny gearing. It got great economy due to the diff, but it could not at any time pull 5th unless downhill and drafting, and is slower than a stock NA 240 sedan, but not by much, mostly first gear.

Most of the trip was done in 4th in 1-1 ratio, and hills are rough with the current gearing and lack of power, requiring you to wind it out a bit and downshift early. One thing I really need is a tach, the sound level is so different in this tin box of a vehicle with most of the insulation stripped and multiple holes in the floor, that im not sure if im running redline, or just barely touching 3grand rpm. A tach will solve this problem.
When I got back and parked the van, I jumped in my DD 240, and was astonished at how peppy it was and how quiet.

As far as temp, the engine maintained a very steady 170 degrees even though it was about 95 all day, and I went over some really bad stretches of road and today am going to to a check of all custom brackets and fastners, as I rattled the heck out of this thing.

Issues noticed are the suspension settled a bit and the camber of the RF tire is horrendous, so bad it actually skids when you make a right hand turn under any speed. An alignment should take care of that.

First gear takeoff is still a real problem. Its hard to describe, but basically its like starting off a regular 240 in 2nd gear. You have to rev high, and still its a slow start, and you are close to the stall line until you are moving a bit. This is my biggest concern at the moment, its definitely drivable, but absolutely not possible to tow with this thing until I improve the gear ratios. First the diff, then Ill see how it does with the transmission, also going to drop tire sizes same time.

I think monday I will be going to the dump, so ill get a new weight measurement after the conversion and see how its changed, and how much heavier this van is than a regular 123.
Im also trying to research what rear end came in the 207D Mercedes TN vans that used the same engine to find an appropriate compromise based on the next weigh in.

Thanks for the update! Impressive mileage. I don't think a lower rearend is going to take away from your mileage as your starts now are high-revving and you can't use 5th. Find the right gear ratio and I think you'll be sittin' pretty!

mdmead wrote:Thanks for the update! Impressive mileage. I don't think a lower rearend is going to take away from your mileage as your starts now are high-revving and you can't use 5th. Find the right gear ratio and I think you'll be sittin' pretty!

I hope so!

Just purchased a 4.56 ratio ring and pinion from Jegs. Im going to grab a spare diff from a yard and have a local place do the ring and pinion swap for me. Will be interesting to see the difference between 3.23 and 4.56 as far as usability, I hope that solves my low end power issue in 1st

With any luck that gearing will allow you to run slightly taller tires (rather than Smaller as you mentioned) and that will get your lowered front end up off the ground a tiny bit. I expect that with those drop spindles you are using, you must cringe at every pothole and large object in your path...

doyoulikeithere wrote:With any luck that gearing will allow you to run slightly taller tires (rather than Smaller as you mentioned) and that will get your lowered front end up off the ground a tiny bit. I expect that with those drop spindles you are using, you must cringe at every pothole and large object in your path...

This is a good point, I did pretty much immediately forget about the drop spindles while driving around. Honestly though, clearance is about the same between the new suspension and drop spindles, and my 200k sagging original suspension and regular spindles. Ground clearance between both is pretty similar, but it is worth remembering that I do have a drop, not a lift as far as the street is concerned.


some more calculation update-
A guy over on the mercedes forums posted a really useful gearing calculator-

http://www.scirocco.org/gears/

so with my current tire size, in 1st gear with the 3.23 diff, I should be going 18mph at 3k rpm, but with the 4.56 diff, ill only be going 13mph at 3k rpm.

Overdrive calculations are pretty interesting-

If my target speed is 65mph in overdrive-
3.23 diff is turning 2239 RPM
4.56 diff is turning 3160 RPM

As a comparison, if my target RPM is 3k in overdrive-
3.23 diff will have the van traveling at 87mph!
4.56 diff will have the van traveling at only 61mph

No wonder I can't pull overdrive, this van couldn't easily break 90 even with the twice the HP 4.3 in it.

By these calculations I should be in a nice torquey 3100 to 3500 rpm at 70 in overdrive. Thats pretty close to stock MB

Thats great. Cant wait to hear about the gear swap results.
I was only thinking about the drops spindles cuz you added an inch or two to the bottom af the crossmember as well and I wondered just how much room you ended up with under there.
Thought it might be sketchy if you crossed a tall speedbump on a angle kinda thing, but I cant see it so I dunno...

doyoulikeithere wrote:Thats great. Cant wait to hear about the gear swap results.
I was only thinking about the drops spindles cuz you added an inch or two to the bottom af the crossmember as well and I wondered just how much room you ended up with under there.
Thought it might be sketchy if you crossed a tall speedbump on a angle kinda thing, but I cant see it so I dunno...

The modified subframe is about the same dimension from below, I added most of the beefiness to the back side of it really. Its lower by maybe the thickness of some 3/8ths steel, but I also removed the skid section when I first did that, so in might actually be slightly higher than stock at that point in the subframe.

Ill try and post a pic of the van from the front showing the ride height soon, but its definitely worth remembering that its lower, not higher. I forget almost every day.