Cummins 4BT & Diesel Conversions Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter #1
Hi Everyone,

I picked up a 2005 Chevy Colorado Z71 3.5L I5 with 240k Miles for cheap. It runs and drives good but the motor needs valve seals bad. (I burned 2 quarts of oil in a 1000 miles) I'm not very fond of the 3.5L atlas engine or its 3.7L replacement. Not a lot of power, not the best mileage and lots of valve and head issues.

This truck is a daily driver for me. I use it to haul a small jet boat (16 ft) but most of the time I'm on the freeway and drive about 80 miles a day so I want to be able to tow a little and more importantly be good on the freeway and get good fuel mileage

The truck has 3.73 Gears and 31in Tires with a 4L60e trans that I plan to keep.

So here is the plan, I picked up an 1985 Mercedes Benz 300TD with 100k miles on the OM617 Turbo Diesel engine that I want to swap into the Colorado. I've owned a 300d before and love that engine.

My parts list is
OM617 Turbo Diesel Engine
US Shift 4L60e Trans Controller
Reuse the gas sensors so all the factory gauges work.
I have a local welding shop to fab up the down pipe and motor mounts
MercedesDiesel4x4 Bellhousing and starter adapter kit
Retain GM A/C compressor

I've done some swaps and builds in the past so I have an idea of what I'm getting myself into but I'm sure I will have some questions and this forum is a wealth of information that I hope to tap into and give anyone looking to take on a swap like this an idea of what it takes.
 

Attachments

·
Registered
Joined
·
15 Posts
Discussion Starter #3
Ok so the Benz is home. This weekend I plan to power wash everything and get the motor out of the car. If everything goes good I would like to change the oil and start it up





 

·
Registered
Joined
·
38 Posts
Very cool project. You don't see mechanical diesel swaps into the newer trucks very often.

The 3.73 gears you have paired with the 4L65 transmission are not going to be great for the OM617. Especially with the 31 inch tires. Your also going to have less power then the out going 3.5L. Personally a 3.0 or 3.5 6 cylinder benz motor may have been a better choice if you are looking to keep the stock gear ratios. If you do re gear I would recommend at least 4.56s at a minimal.

What are your plans for the OM617? Intercooler? Pump mods? Keeping it stock? Etc?
 

·
Registered
Joined
·
15 Posts
Discussion Starter #5
Good questions!

The 3.73 gears are not ideal but I want to drive it before I figure out if I want to change them.

Yes I'm going from 220hp in the chevy 3.5l to 120hp in the 3.0l Bens diesel but what I'm most looking for is reliability and mpg

I want to drive it stock and see where I want to take it, I'm thinking intercooler injectors and pump work. 150hp would be good
 

·
Registered
Joined
·
15 Posts
Discussion Starter #7
I want to retain as many factory options as I can. I would love to retain the factory ECU trans control so the 4x4, Cruise,Reduced Power message, all work the same. I'm going to connect all the factory input sensors I can. I think the only 2 that wont work on the diesel are o2 and MAP sensor. I plan to unplug them and see if it still shifts ok and the Reduced power message does not come on this week
 

·
Registered
Joined
·
38 Posts
150 horsepower to the wheels is probaly not realistic in a OM617 with a 4L65 behind it with out a lot of upgrades (turbo and injection pump). It seems like the pumps are limited to around 125 wheel horsepower which is probaly around 155 at the crank and torque with the pumps cranked up seem to hit around 170-190 torque at the wheels.

You do have tons of space under the hood of the chevy and should be able to keep your AC with some work. Some of the gauges will not be a problem however the tach and message center might be. Your going to of course throw check engine codes if your running the ECU with the sensors not working properly but you can work around that.

OM617s are not known for extreamly good MPG. Even in the auto 300D cars they typically get around 30 mpg in real world driving with a weight of around 3600lbs. My fear would be the Colorado is probaly close to 4600lbs and the gearing will have you way out side of the OM617 operating range.

Consider a 300D with a 1.00 top gear with 3.08 rear and 24 inch tire gives you about 2900 rpms at 70 mph. With the 4L65 and it's 0.70 top gear paired with your 31 inch tires and 3.73s your only going to be turning about 1900rpms at 70 mph. That's a 1000 rpm difference at cruising speed in a vehicle that has to be at least 1000lbs more. Also the 4L65 only has a 3.00 first gear so she may be sluggish getting up to speed.

Personally a 5 or 6 speed swap would be on my list if you don't plan to re gear right away. It might also make the swap a little less complicated.
 

·
Registered
Joined
·
15 Posts
Discussion Starter #9
When I say 150hp I'm talking to the crank. All gauges will work normally. I just ordered a reluctor ring and will reuse the factory crank sensor for the tach and its needed for the stock trans control. The check engine light will be on because of no 02 or map sensor but all other lights should be off. I agree about the gearing It will most likely be changed after the swap is complete
 

·
Registered
Joined
·
4 Posts
Subscribed, very interested to see how this turns out. I've been batting around the idea of dropping a 4bt + 4l80 into my 05 Colorado.

Can I ask why you're using the US Shift trans controller? I have HP Tuners, but I guess the trans controller does the same job for the same price and a bit easier?
 
P

·
Guest
Joined
·
0 Posts
With only 31 inch tires i would think you would be ok unless you are going to tow a lot. If you find yourself constantly hitting passing gear to maintain crusing speed up moderate hills, I'd keep her 3.73. I remeber reading the 700r4 was a popular swap in the MB because of better gearing for the om617, how far off is the 700r4 from your 4l65? I thought the 4l60 and 700r4 shared the same gear ratios but it's been years since i researched that info.

If im building for mpgs and not off road or towing performance I'll always sacrifice take off speeds to keep highway rpms down...my rule of thumb is if i can keep up with traffic from a red light changing to green without stomping on it im good!
 

·
Registered
Joined
·
841 Posts
I had a OM617/700R4 Jeep and had a love/hate experience with it mainly hating the trans. The HUGE gap between 1st and 2nd along with getting the tv cable adjusted properly for line pressure/down shift. 4.11 gears minimum, 3.73 no way. I think a stick is the only option to help overcome this motor's shortcomings.
 
1 - 15 of 15 Posts
Top