Is a free Chevy 5.7 diesel a gift or a curse???

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hawkiwi's picture
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Joined: 06/19/2005

A friend of mine has offered to give me a '79 Chevy Caddy that has an '84 GM Targetmaster 5.7 diesel with 40K on it. That's right, he is giving it to me for nothing, simply because he knows I want to experiment with WVO. That being said, here are my questions:

1) Is he really a friend (i.e. giving me the much maligned 5.7)

2) In your collective opinions, is this thing even worth experimenting on (I have in mind to drop it into an older (1980's) Chevy pickup).

My ultimate objective is to acquire a 94 or 95 Suburban and convert that family wagon into a WVO machine. Any thoughts would be appreciated.

TDIguy's picture
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Joined: 06/07/2004

I allways have a hard time passing up something that works and is free. I like the old diesel engines myself (anything before 2000) it seems they were build a lot more rugged back then. I would say unless there is something he is not telling you about the truck it is worth experimenting with and converting. If it does not work out you can allways pull the conversion kit out. If you can spare the time experimenting is allways at the very least a learning experiment.

thtguy's picture
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Joined: 10/04/2004

they are dogs, but only because they have 75 HP

fyremanbil's picture
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Joined: 05/17/2005

The 5.7 was a horrible diesel engine, mostly because it is a converted gas 5.7 (the 6.2 is a pupose built diesel and OK). It may last longer on veggie just because it burns a little slower and is easier on the engine.
If you take this car, don't put any money into it. When it it breaks, push it to the side of the road....and leave it there

Pyrotechnic's picture
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Joined: 05/15/2005

Depends on the condition of the car.

If the car is in really nice shape, then i'd say drive it till the 5.7 blows up then swap a 6.2 or 6.5 in when it dies. Should be a really nice greasecar

If the car is really beat up and not worth saving, then just drive it till the wheels fall off or the motor blows up, then junk it.

I'd say dont even put a kit on the 5.7, just make sure the WVO has no water in it, and just blend with diesel.

tenknots's picture
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Joined: 11/29/2004

An '84 targetmaster engine is liable to be a pretty good one - most of the bugs worked out. The last one I had I sold it with 250k on it.

Don't expect it to be a Mercedes...

veggiesuburban's picture
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Joined: 09/01/2004

Quote:
Originally posted by: fyremanbil
The 5.7 was a horrible diesel engine, mostly because it is a converted gas 5.7 (the 6.2 is a pupose built diesel and OK). It may last longer on veggie just because it burns a little slower and is easier on the engine.
If you take this car, don't put any money into it. When it it breaks, push it to the side of the road....and leave it there
The 6.2 and later 6.5 were modified big block gas chevrolets just as the 350 diesel was a modified gas small block. At the time of their design GM owned Detroit Diesel and used the gas block design for each as a starting point for the engines. They did learn a lot with the 350 in the beginning, but the Goodmark replacements should hold up well.

These motors are dependable, but don't ask too much of them. They are in a different class than the offerings of Navistar (FORD) and Cummins (Dodge), but for use as daily transportation and WVO they are great and a good value.

-------------------------
1995 Chevrolet 3/4 ton 2wd Suburban 6.5 Turbo Diesel, 4L80-E 4spd auto. Modified Greasel tankless conversion with Racor 1000FH filter, electric heater.

Pyrotechnic's picture
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Joined: 05/15/2005

The 5.7 diesel is an OLDSMOBILE 350 based design, not a Chevy 350.

The 6.2 and 6.5 were done by Detriot Diesel, both being totally new designs as DIESEL engines. They share nothing with any of GM's gas engines.

If I recall correctly, Detriot didn't design the 5.7 at all. GM used a lot of technology they used in NASCAR and figured if it could withstand 700HP in gas form then it was plenty strong for a diesel.

hawkiwi's picture
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Joined: 06/19/2005

You guys have been really helpful! I'll keep you informed on my progress. I think I'll get the car on the weekend of the 4th if all goes according to plan.

Thanks again!

Worken2much's picture
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Joined: 02/06/2005

The early 5.7 liter diesels were very troublesome indeed, I know of one that went only 17 miles before it broke the crankshaft. HOWEVER, as the years wore on GM did indeed improve theses motors substantially.

The 84 & 85 engines were quite good. With just a little care they would last 200,000 miles or possibly more. They were not a ball of fire but adequate. They made 120 hp per the manual I had for an 84 Oldsmobile Toronado. Great road car, 30 mpg at 70 mph with the air conditioning on.

Take the car, buy your good friend lunch.....but save the grease.

-------------------------
Always been good at getting by.

350GMCDiesel's picture
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Joined: 01/05/2006

Contrary to popular belief the 5.7L GM diesel was NOT a converted gas engine. What it was, was GMs first attempt to build a diesel and it was rushed to the market to boot, not enough R&D was done. The early versions of the 5.7L were, shall we say, less than perfect but so was the market. Near the end of the 5.7L diesels life the engines were actually decent well running and put together engines. The engines failure is attributed to may things, first the average person who bought cars and trucks with this engine were not familiar with operating diesels, second technicians who worked on the cars and trucks were not familiar with diesels and often used the wrong types of lubricants in the engines, and third diesel fuel quality in the late 70s and early 80s was horrible.

The only thing the 5.7L diesel shared with the 5.7L gas was tranny bolt patterns and motor mounts. Other than that they were completely different engines. If you were working on both and only looking at the crank from the underside you would see very little similarities.

The 5.7L diesel was rushed to the market so it had to fit in existing products and run down existing assembly lines. GM marketing came up with the idea that if the displacement were the same it would be easier to convince its customers that diesels were just as easy to own and operate as gas.

In many ways this engine was a failure but the later generations of them, if cared for, last for a long time.

JeffNLisa's picture
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Joined: 10/07/2005

And in fact, even the early generations are durable throughout the long block. Many racers today seek out the early 5.7 GM diesels because of this.

The shortcomings that caused it to fail with the quality of diesel in the 70s had largely to do with water in the fuel and a pump that was intolerant of water (as most are).

When water would affect the pump, that would cause it to inject irregularly and off timing; and eventually adding water into the injection.

Fluid does not compress. So when water would get into the cylinder while running, when the volume was used up before TDC on the compression stroke, hitting that fluid would do more damage than hitting a block of steel.

Then POW goes the connecting rod, or the crankshaft, or the piston, or some combination. People who knew how to use and work on diesel engines at that time routinely got 200k, 300k and more, even on the first generations of them.

I was always amazed at how common the "knowledge" was that they were just 350 gas blocks refitted for diesel. Huge numbers of them failed, that's true. But it's possibly a reflection of how well GM read the fickle and uninformed (but quick to decide and blame) American Public at the time, that the myth about the gas-block spread.

If you have one that has not had this happen to it, and has a good pump and you use good fuel, it will continue to last many many miles.

I had a friend who had a late 70s one that his dad bought used, 2 years old with 37,000 miles for $800. There was nothing wrong with it, just the owner was just so scared of it that he wanted to get rid of it. Last I saw him, he had over 470k miles on it, and almost all its life it has been used to tow a boat. Never has been opened, had any seals changed, or anything internal broken or repaired.

Hawkiwi, if it is running properly now and has not had any of the abuses described, you should be able to keep it that way just with normal proper care.

Jeff

-------------------------
98 Jetta TDI, Frybrid kit 12/05.
======> 4,200 miles in first greasy month, on 10-12 gallons of dino!!
97 Buick Park Avenue, Jeff hates but Lisa LOVES
(maybe can persuade her to swap it for a Mercedes 300 diesel, and do SVO on it. Pray for me!)
86 Nissan Pathfinder, WISH was diesel. And an 86 Mustang SVO. If it was diesel, would make it an SVO SVO !!

And a SHAMELESS plug for my own business- www.prepaidlegal.com/go/lisaleon
Those who HAVE a Pre-Paid Legal membership are MUCH more likely to get good legal advice than those who DON'T.

oldmopars's picture
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Joined: 09/28/2005

I am interested in any news on this Free 5.7L Caddy you got.
I have a 5.7L and may be getting is little brother a 4.3L Olds also. I like them, they are not a Mercededs or Toyota, but not bad when they are sold to you cheap.

-------------------------
82 Oldsmobile 98 Regency Diesel
Working on home-brew cheap conversion

tenknots's picture
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Joined: 11/29/2004

I had an 84 with 235k. Good engine. And not 75 HP, more like 120. Quiet and smooth and able to lay down a black cloud with no trouble. Mine was in a 5000 pound station wagon and could cruise on the highway in comfort and get nearly 30 mpg.

Don't pass it up because of old wive's tales.

mr booly's picture
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Joined: 12/18/2005

Quote:
Originally posted by: veggiesuburban
Quote:
Originally posted by: fyremanbil
The 5.7 was a horrible diesel engine, mostly because it is a converted gas 5.7 (the 6.2 is a pupose built diesel and OK). It may last longer on veggie just because it burns a little slower and is easier on the engine.
If you take this car, don't put any money into it. When it it breaks, push it to the side of the road....and leave it there
The 6.2 and later 6.5 were modified big block gas chevrolets just as the 350 diesel was a modified gas small block. At the time of their design GM owned Detroit Diesel and used the gas block design for each as a starting point for the engines. They did learn a lot with the 350 in the beginning, but the Goodmark replacements should hold up well.

These motors are dependable, but don't ask too much of them. They are in a different class than the offerings of Navistar (FORD) and Cummins (Dodge), but for use as daily transportation and WVO they are great and a good value.

-------------------------
1995 Chevrolet 3/4 ton 2wd Suburban 6.5 Turbo Diesel, 4L80-E 4spd auto. Modified Greasel tankless conversion with Racor 1000FH filter, electric heater.
Absolute nonsense!

6.2 and 6.5 have nothing in common with the BBC. They were designed as diesels. Goodwrench replacements for the the 350 Olds diesel were the same crap as the originals.

If I needed an anchor for a yacht, I would take the free Caddy.

redly1's picture
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Joined: 07/29/2005

Ive read different opinions, but one guy said that around 84/85 (right before GM axed the car diesel engines) they finally got it pretty much right 9not perfect, but WAY better than before.

if it's free, I say go for it!

redly1's picture
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Joined: 07/29/2005

Quote:
Originally posted by: thtguy
they are dogs, but only because they have 75 HP
WRONG

http://members.tripod.com/~A350Diesel/specs.html

even the V6 diesel had 85HP

lots more Olds Diesel info
http://members.tripod.com/~A350Diesel/350tech.html

oldmopars's picture
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Joined: 09/28/2005

As an OWNER AND DRIVER of both a Olds 5.7L and an Olds 4.3L I can tell you that what ever the HP it is plenty. My Big Olds has the 5.7 and it weighs 4000lbs empty, it will push you back in the seat and won't stop pulling till it hits over 100mph. The little Olds has the 4.3L, it has plenty also. I know it will out run a Mecedes, I have driven them too.
I will take ANY GM 5.7L or 4.3L Diesel anyone wants to get rid of.
BTW, my 4.3L has 113K on it and my 5.7L has about 125K, I got them both for under $1000 total.

-------------------------
82 Oldsmobile 98 Regency Diesel
Working on home-brew cheap conversion

JeffNLisa's picture
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Joined: 10/07/2005

Well old,

I would like to see them and drive them both!

I had an 80 Chevy Citation in 1990. Had a V-6 gasser. It was a heap of shit to be sure. But it was extremely powerful, and one of the most comfortable cars I ever drove. And if you like them and do the work yourself, then where's the harm?

It got in my wallet heavily. But my Mustangs got in my wallet EVEN MORE. To be fair, I always bashed them too for what pieces of shit they were, but i liked them. Same with a Harley. Go figure . . .

And yours may not be problematic at all. I hope not. I give you 100% vote for BOTH your Olds diesels.

Get 'em converted! ** Take pics! ** Drive on free WVO! ** SHOW US!!

Jeff

______________________
98 Jetta TDI, Frybrid kit 12/05.
======> 4,200 miles in first greasy month, on 10-12 gallons of dino!!
97 Buick Park Avenue, Jeff hates but Lisa LOVES
(maybe can persuade her to swap it for a Mercedes 300 diesel, and do SVO on it. Pray for me!)
86 Nissan Pathfinder, WISH was diesel. And an 86 Mustang SVO. If it was diesel, would make it an SVO SVO !!

And a SHAMELESS plug for my own business- www.prepaidlegal.com/go/lisaleon
Those who HAVE a Pre-Paid Legal membership are MUCH more likely to get good legal advice than those who DON'T.

oldmopars's picture
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Joined: 09/28/2005

I will post pictures soon, right now the weather is real bad and my camera is not working well.
See my other post "Score" and you will see one of the things I like about them.

-------------------------
82 Oldsmobile 98 Regency Diesel
Working on home-brew cheap conversion

Cabover's picture
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Joined: 11/03/2004

Quote:
Originally posted by: hawkiwi
A friend of mine has offered to give me a '79 Chevy Caddy that has an '84 GM Targetmaster 5.7 diesel with 40K on it. That's right, he is giving it to me for nothing, simply because he knows I want to experiment with WVO. That being said, here are my questions:

1) Is he really a friend (i.e. giving me the much maligned 5.7)

2) In your collective opinions, is this thing even worth experimenting on (I have in mind to drop it into an older (1980's) Chevy pickup).

My ultimate objective is to acquire a 94 or 95 Suburban and convert that family wagon into a WVO machine. Any thoughts would be appreciated.
My advice:

Take the car. Experiment, tinker and drive it at times that you do not have to depend on it.

As a regular ride to work might leave you high and dry and short your weekly pay or get you fired for not showing up at work. A good Saturday ride around and "honey do" runner.

Take what you learn and apply the lessons (and maybe some of the parts) to a good diesel, a M.B. would be my choice, there are a lot of good modern Diesels.

Cabover

-------------------------
A little grease goes a long ways!

BlackCloud's picture
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Joined: 03/05/2006

Biggest problem with the Olds 5.7 Diesel was using a gas block versus a block designed for a Diesel. Primary reason for failure was and still is the crankshaft. The 5.7 crank weighs 85 LBS. The 6.2 weighs in at 200 LBS. Which one do you think would handle 23 to 1 compression ratios more easily? Drivers who warm em up for 5 minutes or so before driving generally had fewer problems.

-------------------------
Jim
1985 M-1009