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Folks, I'm a newbie to the site so thanks for letting me join. I've got a 1951 Chevy 3100 half ton pickup that's been in my family since it was new. It was last driven when I was in high school 40 years ago and has a seized up original 216 spash oiler. My goal is to get advice and guidance from you good folks on the very best combination to achieve maximum MPG on an interstate cruiser. I'm open to engine types, transmission types, adapter plates, rear end swaps and rear end ratios, tire size recommendations, etc. I'm not planning on pulling anything with this truck, just want to get a fantastic mpg cruiser on the interstate as I drive an hour 2 hours per day to work and it's all interstate. I've had some old Mercedes diesels in the past and love the way they run but just am not sure if this is the right choice for what I'm after. I'm not a fabricator and have never rebuilt an engine or transmission so ideally whatever I do won't require a lot of cutting or modification but realize that there's got to be some to pull off such a swap. If this topic has already been covered on the site, please excuse my ignorance and if you will, point me in the right direction. I'd just like to start with the end in mind of getting a 30+ mpg interstate cruiser. Thanks for your help in laying out my "recipe". This should be fun!
 

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That is a great family heirloom. I always liked those old Chevy and GMC trucks. At interstate speeds, the aerodynamics are working against you. These trucks have an air drag somewhere between a brick and a cinder block. I'm NOT saying that 30+ MPG at interstate speeds is impossible, just NOT likely at your skill level (or at my skill level). My Ford F150 swap (see signature below) took a long time, and it is simpler that the Chevy 3100 swap. It has 37 states on it, probably 2 years before I dared take it on a long trip, but never was needed for a daily commute. Maybe low 20 MPG??, I have not driven it much since having the Bosch VE injection pump rebuilt.

For the daily grind commute, maybe consider a stock VW TDI diesel (the whole car) or a Toyoda Prius (Again the whole car). Reliably showing up at work has to be a big factor in your planning.

Maybe someone else has a better idea?

Russ
 

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That is a great family heirloom. I always liked those old Chevy and GMC trucks. At interstate speeds, the aerodynamics are working against you. These trucks have an air drag somewhere between a brick and a cinder block. I'm NOT saying that 30+ MPG at interstate speeds is impossible, just NOT likely at your skill level (or at my skill level). My Ford F150 swap (see signature below) took a long time, and it is simpler that the Chevy 3100 swap. It has 37 states on it, probably 2 years before I dared take it on a long trip, but never was needed for a daily commute. Maybe low 20 MPG??, I have not driven it much since having the Bosch VE injection pump rebuilt.

For the daily grind commute, maybe consider a stock VW TDI diesel (the whole car) or a Toyoda Prius (Again the whole car). Reliably showing up at work has to be a big factor in your planning.

Maybe someone else has a better idea?

Russ
Russ, thanks for the response and will make note of that. And it's odd you mention a VW TDI as that's what I drive back and forth to Nashville TN every day now. Bought it new in 2014 I think it was and have 178k on it, get's an average of maybe 42-44 mpg and an excellent transmission and of course, it's a diesel. Would a VW Passat TDI engine be a good choice in a Chevy 3100 you think? Harry
 

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Harry,

I (briefly) looked at a VW TDI conversion for a 1994 Nissan pickup truck. This requires converting from front wheel drive to rear wheel drive. At the time (about 9 years ago), I could not identify an overdrive transmission option that was "budget friendly", money was tight at the time. We sold the Nissan to the nearest junkyard.

A quick couple of Google searches:

Suzuki and Toyoda transmissions, I was looking at these 9 years ago.


The discussion of TDI and M-TDI (VW TDI engine converted to a manual fuel injection pump) engines is worth reading.

Maybe 9 years ago, I visited his shop in the Ontario, CA area. I was quite impressed with him. He had no recommendation for a transmission for the Nissan conversion. He did look at, and like my 4BT conversion (see link below). He has since moved to Victorville, CA.

This web site has not changed much in the last years. The updates state that the availability of good used German engines has changed.

I have NO feel for a Passat TDI engine in a 1/2 Ton pickup. Other that a 4bt in an F150, the only other diesel is a Detroit Series 60 / 10 speed Roadranger in Class 8 tractor (driving school and a few weeks with Swift (Sure Wish I Finished Training - Quit before my probation was completed)).

Russ
 

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If you want to go 8V tdi and tall highway gearing you'll want a better turbo setup. I have a BMM 8V 2.0 TDi which comes with a really responsive GT1646V (I think) variable vane turbo that boosts early (max torque 1500rpm) and can still support about 120kw (170hp). I believe those manifolds and turbos bolt to the 1.9's but a VW nut can confirm or deny.
 

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high gears and as low as you can go. I found on my 4x4 4bt swap that adding compounds and more fuel didn't change the mileage, but lifting it another 3-4 inches killed almost 5mpg....oops
 

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high gears and as low as you can go. I found on my 4x4 4bt swap that adding compounds and more fuel didn't change the mileage, but lifting it another 3-4 inches killed almost 5mpg....oops
That's good to know, thanks for the advise. I had planned to lower it about 3 inches and 4 inches at the max so have been studying up on that but hadn't thought about the added wind resistance and worsening mpg so thanks again. Harry
 

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I think an MPG optimized 4BT pickup will be around 25 MPG average for mixed driving.

I would say it's easier to get a bigger heavier vehicle to eek out 25 MPG with a 4BT than it is to get a light little vehicle past 30.

I took my first 4BT powered pickup on a 2000 mile 2 week road trip with my dog and dirtbike. I never went over 55 MPH. I got 29.2 MPG average for the trip.

If I was really trying to build a record 4BT mileage getter it would be in a car and I might just take the turbo off and run N/A high compression pistons.

I bet the TDI would do better for a highway extreme MPG getter old Chev pickup.
 

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My F150 (see signature below) is tweaked for long interstate driving. Going back over my notes, I find a few trip mileages in the 23 to 25 MPG region - 75 MPH speed limits out here. That sounds about the same as other results posted here. One needs to average over several fills, ideally 1,000 miles or more.

Not a lot of notes, I was on vacation and retired from scientific data gathering. I suspect the MPG got worse as the seals failed in my 1986 VE injection pump. I recently sent the VE pump out for a rebuild - Due to COVID, not traveling - getting 23 - 25 MPH on fill ups (local travel). Last road trip was 3 years ago.

Also acquired a 1962 Volvo PV544 that is getting some of the road trips.

I second investigating a VW TDI - Last time I looked, the rear wheel drive transmission options were limited (my budget was even smaller, and I already had the F150).

Russ

EDIT: "investigating"
 
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Discussion Starter · #10 ·
Thanks Russ, will check out the VW TDI but do not know where to go on this VW front wheel drive vs current rear wheel drive issue. Maybe I can find some info out here on that too. Harry
 

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Google "vw tdi transmission adapter" - Most of that is new to me, I last looked about 9 years ago.

Also read this web site to get up to speed on VW diesels.


I visited his facility about 9 years ago, they impressed me. They moved from Ontario, CA to Victorville, CA a few years back.
At that time, he did not have any recommendations for engine adapters or rear wheel drive transmissions. It was not his area of expertise.

Russ
 
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Discussion Starter · #12 ·
Google "vw tdi transmission adapter" - Most of that is new to me, I last looked about 9 years ago.

Also read this web site to get up to speed on VW diesels.


I visited his facility about 9 years ago, they impressed me. They moved from Ontario, CA to Victorville, CA a few years back.
At that time, he did not have any recommendations for engine adapters or rear wheel drive transmissions. It was not his area of expertise.

Russ
Will do and thanks again. Harry
 

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TDI to jeep adapters are available giving you a 5 and 6 speed close ratio manual option, you would likely need to do a mod to the 4x4 tail housing but I do not see that being too big of an issue.
here is the first link I found but there are many options now.
 
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I have the same truck Basicly sitting here.
I plan to swap a kubota diesel with a nv3500 or ax15 transmssion. I am trying to figure out what suspension to run but I may pull a front and rear suspension from a jag that I have sitting behind the shop. The rest of the truck will keep exactly as it sits. Was a farm truck. I got the 216 running after 30 years but it’s not staying in.

looking forward to watching your build
 

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Hey man! I did this swap 9 years ago. Here is what it has evolved into. Currently runs consistent low 11s and makes 550whp and 878ftlbs torque at 65psi. I used to get 32mpg and now get around 28 with the s366 and colt cam. Going 125mph in this truck is extremely sketchy with the original front axle and steering box 😂
131468
131469
 

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Folks, I'm a newbie to the site so thanks for letting me join. I've got a 1951 Chevy 3100 half ton pickup that's been in my family since it was new. It was last driven when I was in high school 40 years ago and has a seized up original 216 spash oiler. My goal is to get advice and guidance from you good folks on the very best combination to achieve maximum MPG on an interstate cruiser. I'm open to engine types, transmission types, adapter plates, rear end swaps and rear end ratios, tire size recommendations, etc. I'm not planning on pulling anything with this truck, just want to get a fantastic mpg cruiser on the interstate as I drive an hour 2 hours per day to work and it's all interstate. I've had some old Mercedes diesels in the past and love the way they run but just am not sure if this is the right choice for what I'm after. I'm not a fabricator and have never rebuilt an engine or transmission so ideally whatever I do won't require a lot of cutting or modification but realize that there's got to be some to pull off such a swap. If this topic has already been covered on the site, please excuse my ignorance and if you will, point me in the right direction. I'd just like to start with the end in mind of getting a 30+ mpg interstate cruiser. Thanks for your help in laying out my "recipe". This should be fun!
I know I'm going to cop flack from the hard core diesel guys on a diesel forum, but.................

You can get reasonable MPG from a Blueflame if you use common sense! [This is a family heirloom , so consider this]
Put a 235 into it [a bolt in] but add a 5 speed t5 or Tremec trans to it.
With the engine ,try and get the compression up to about 9.5:1 to 10::1 + then starve the engine back with intake duration on the cam.[talk to a good cam grinder]
Run a HEI distributor and a Holley economiser 1 barrel carb [from a 200 Ford six]

What you're trying to do here ^^^^ is get a gasoline engine to have diesel manners.

If you must go down the Diesel "rabbit hole" use an Isuzu 4BD1-t with an Isuzu SAE bellhousing [make a simple adaptor plate] and use a NV4500 Chevy trans.
 

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If I was really trying to build a record 4BT mileage getter it would be in a car and I might just take the turbo off and run N/A high compression pistons.
You're way better with a turbo. Every time. NA diesels usually can't get within 10% of the efficiency of a turbo model. The only exceptions are those with really crappy turbos (Perkins AD3.153 vs AT3.152).
 

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Folks, I'm a newbie to the site so thanks for letting me join. I've got a 1951 Chevy 3100 half ton pickup that's been in my family since it was new. It was last driven when I was in high school 40 years ago and has a seized up original 216 spash oiler. My goal is to get advice and guidance from you good folks on the very best combination to achieve maximum MPG on an interstate cruiser. I'm open to engine types, transmission types, adapter plates, rear end swaps and rear end ratios, tire size recommendations, etc. I'm not planning on pulling anything with this truck, just want to get a fantastic mpg cruiser on the interstate as I drive an hour 2 hours per day to work and it's all interstate. I've had some old Mercedes diesels in the past and love the way they run but just am not sure if this is the right choice for what I'm after. I'm not a fabricator and have never rebuilt an engine or transmission so ideally whatever I do won't require a lot of cutting or modification but realize that there's got to be some to pull off such a swap. If this topic has already been covered on the site, please excuse my ignorance and if you will, point me in the right direction. I'd just like to start with the end in mind of getting a 30+ mpg interstate cruiser. Thanks for your help in laying out my "recipe". This should be fun!
RPM... above lugging if you can run 1500 RPM you'll be a lot more efficient that 2000RPM.. that hold true for 6bts.. 1995 ram 2500 with 411 gears and NV4500.. if I run 58Mph... I get 24 MPG... when I try to run with the freeway crowd... down to 20mpg...
 
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