View Full Version : Consider the Cadillac 350 Diesel
08-09-2000, 06:22 AM
I'm hoping that I can get some really good feedback from Joe and Scotty on this, or just about anyone who's got some common knowledge of these motors.
My *brand new* 2600 miled 360 developed a low-oil pressure bad Great Googley MoogleyGreat Googley MoogleyGreat Googley Moogley attitude. Of course I was ticked off but I had to get to work. About a week ago, after driving on it about 400 miles with 10psi at 50mph, the crank broke on me. Right by the rear main.. the motor groaned, whined and the truck ceased to move forward. The motor still ran, but the crank being broken stopped my forward movement. Atleast I think it was the crank that broke... I shut it off, and upon trying to restart the motor, the starter would whine, the flywheel would turn, but all of the pulleys didn't move nor did the rotor in the distributor! I've just about had enough with AMC motors... if its not a leak, its something major.. ALWAYS! This thing has been extremely underpowered from the get-go as well. This all happened about two weeks before I was about to drive it 940 miles to go and trade the truck off so I can pursue my M-715. So I'm stuck with a busted truck in the driveway AGAIN.
Anyhow, here's my questions. I have access to a complete... I mean carb to pan, flywheel to fan Cadillac 350 V-8 diesel. This thing is a 5000 mile old crate motor. Its in immaculate condition. Did I mention is carbureted? Can we say NO stupid GM injector pump failures? This motor was in a front-wheel drive early 80's Cadillac Seville... the one with the sloped rear end on it. This was a replacement of the original motor in it. I know the transmission isn't worth a flip to me, but I'm wondering if the torque converter would work in the application I'm thinking of.
***The Question part***
Can I bolt this motor up to a TH400 from a 70's Chevy 4x4? I would imagine the 350 diesel is a re-tooled SBC wouldn't it?
Will I need to change the motor mounting system on my frame?
How will I wire up the thing for the glow plug light? Will I need the wiring system out of the car too? If so will all my gauges work still?
Will my NP208 transfer-case bolt up to the TH400? Will I need the Chevy NP208 adapter to make that part work? I need to keep it driver's side drop or I'd use the chevy's 208 case that's still attached to the TH400.
Can I use the stock feul lines and tank? This is the one thing I'm terrified of. I'd imagine that there is a mechanical feul pump on the 350 diesel like my 360's got. if I could get away with using the stock feul lines and tank, then I think this will be a feasable and not so expensive swap.
How good are the 350 Diesels? when it was in the car it felt pretty torquey, and it was front wheel drive! I bet with my 3.73's track lock and TH400, it should sing!
I'd like to keep the truck as un-bastardized as possible and just drop this motor/tranny in without having to fool with too many things. Especially the stock wiring harness if I can get away with it! Thanks for everyone's response in advance, I need to jump on this project as soon as possible.
86 J-20 "The Rusty Dinosaur"
The 350 is pure junk. Some folks have bad mouth GM dsl's but I've seen many 6.2's and 6.5's run well over 300,000 miles. They do have flaws though...And "no" they aren't gas motors converted to dsl "but the 350 is" http://www.cs.colostate.edu/~zeimet/ubb/frown.gif
Stay away from the the dsl 350. It was a bad design/idea from day one. You can spend a fortune rebuilding one and if you get 30,000 trouble free miles out of it call the "Guiness Book of World Records" folks, they'd be gald to here from you(so would GM).
08-09-2000, 08:40 AM
Snake eyes I would sell that 350 dsl and buy a SBC 350. You'll be much happier with it cause theres so much stuff you can get for them and cheap too.There also very reliable and easy to work on. This I what I'm thinking about doing with my J20 does anyone know if I get the GM TH400 case to go with the SBC will it bolt to my Q-Trac? And will the Q-Trac output shaft and guts go into it?
08-09-2000, 07:40 PM
is this cadilac diesel the same as the deisel that you would find in an olds delta 88? a friend of mie used to have one of them-it was something. the alternator went out on it one time,and we had a helluva time getting it started,even using 2 cars to jump the batteries seperately. this is one thing youll need to consider with any diesel swap-it takes alot to crank over a motor with about a 20 to 1 compression ratio,so youll pretty much have to have a second battery somewhere. the thing that confuses me is the carb thing- ive never seen a diesel that was not fuel injected.hmmm...
anyway, i was under the impression that the gm diesel was an olds engine-not a chevy,but this might be wrong. if this is the case,youll prolly have to use a tranny with a buick/old/ponitac bellhousing. otherwise,you can use a chevy 350 or 400. the gm 400 can work with the quadra trac by swapping tailshafts. the gm 350 can be made to work with a 208,but youll have to use a GM factory 208 adapter and tailshaft,AND a gm 208. the input splines are different. actually,you cant do that because a gm 208 is passenger side front diff.hhmmm... youll have to swap a gm 208 inout gear into your jeep 208. that or simply use a whole drivetrain(700r and NP 241) from a newer ifs truck,since it will also have a driver side diff. or swap your front axle,i guess...
i dont believe a th400 ever came with a new process case,so there are not any factory adapters or tailshafts for this swap. youll have to call advance adapters on that one.
last and not least,i thought that the actual goodwrench diesels were ok-some of the engines put into cars were indeed converted gas engines with diesel heads,and the bottom end just wasnt strong enough. if you got it replaced by a real diesel engine,the block and bottom end was alot beefier and less likely to spit out its pistons.
im still investigating the eagle 904 to small block possibility-like dumb asses we left the flywheel(authors note: whenever i type "flywheel" i am actually refering to an automatic flexplate.force of habit) attached to the engine in the woods. the small block flywheel to convertor pattern is bigger than the pattern of the gm-like 904 convertor. im still hoping to find a factory piece that will bolt to the engine and convertor, but an adapter flywheel prolly wont cost alot more than a new factory one. its also possible to maybe make an "adapter convertor" of sorts,so im gonna go to the convertor shop and investigate that tomorrow...
i love my six,bt i will prolly do the SBC thing,since it shouldnt cost me much,and im curious to see if i can make it work. it willbe cool to be able to buy cheap parts- ifit breaks down at the side of the road,walk to the nearest 7-11 and buy spark plugs,cylender heads,complete engines... http://www.cs.colostate.edu/~zeimet/ubb/biggrin.gif you can usually buy running 305s all day long for almost nothing...
85 grand wagoneer
258 with motorcraft 2bbl/904/twin stick dana 300/dana 44/welded amc 20
38x15.5 gumbo mudders
snorkel/dual batteries/onboard air/"custom" convertable
3 inch body lift/mostly stock suspension/"modified" fender openings
custom front/rear bumpers and brushgaurd
possible small block chevy "test" swap in near future
08-09-2000, 08:00 PM
Warning! Warning! Danger Will Robinson!..... I dont know about the diesel's but I have a friend that just sold one of those 80's Caddys that had a V8 some 260 or something mabye, cant remember which motor it was.. I think it may have even had an aluminum block (does this sound right) anyway the motor was wasted. with really low milage.. A guy that used to work at a dealership told him that everytime they sold one of those caddys. they would order a replacement motor for it.. cause it was only a matter of time before one of em came back and needed it..
88 Grand Wagoneer
NP 229 (Funky)
Bone Stock (for now)
NO RUNNING BOARDS!
08-09-2000, 08:18 PM
The 350 GM diesel was a bastard of a motor. I believe it was not a converted gas engine block but was close to it. Anybody familar with Olds has heard of Joe Mondello. He is the Olds guru (I still have the 455 olds in my jet boat) and he has a kit to convert the 350 olds diesel into a gas motor. He says you can build a stout motor using that setup. As a diesel it is worthless. The 6.2/6.5 Gm diesel was designed by GM with Detroit Diesels help and although it has some issues generally can and will go the distance. Sounds like what happened to snake is a good example of why one should ensure that a 360 rebuild includes making sure that the timing cover is replaced or at least ensure that it is in great shape. Putting a oil pump rebuild kit in doesn't help in a bad cover. The gas Caddy engine is the 4100 or 4.1 and was known for a number of shortcomings in its early versions especially. It was a aluminum block with iron heads.
08-10-2000, 03:35 AM
<BLOCKQUOTE>quote:</font><HR>Originally posted by Snakeyes_Tx:
My *brand new* 2600 miled 360 developed a low-oil pressure bad Great Googley MoogleyGreat Googley MoogleyGreat Googley Moogley attitude.
the crank broke on me. Right by the rear main..
I've just about had enough with AMC motors... if its not a leak, its something major.. ALWAYS! This thing has been extremely underpowered from the get-go as well. This all happened about two weeks before I was about to drive it 940 miles to go and trade the truck off so I can pursue my M-715. So I'm stuck with a busted truck in the driveway AGAIN.<HR></BLOCKQUOTE>
I can imagine your disappointment. The problem is obviously with the quality of the rebuild, not the motor itself; any motor that is improperly assembled will do what yours did. So, I'll leave the advice to rebuild another 360, or install a good-running used one, right here...
<BLOCKQUOTE>quote:</font><HR>Anyhow, here's my questions. I have access to a complete... I mean carb to pan, flywheel to fan Cadillac 350 V-8 diesel. This thing is a 5000 mile old crate motor. Its in immaculate condition. Did I mention is carbureted?
This was a replacement of the original motor in it. I know the transmission isn't worth a flip to me, but I'm wondering if the torque converter would work in the application I'm thinking of. <HR></BLOCKQUOTE>
If it's carbureted, it's not a diesel. It may be a converted diesel (an extremely common conversion), or a real gasoline engine, but if it has a carburetor or any kind of throttle body, it's not a diesel.
<BLOCKQUOTE>quote:</font><HR>***The Question part***
Can I bolt this motor up to a TH400 from a 70's Chevy 4x4? I would imagine the 350 diesel is a re-tooled SBC wouldn't it?
Will I need to change the motor mounting system on my frame?<HR></BLOCKQUOTE>
It is actually an Oldsmobile 350 engine, with the larger main journals from the 455 big-block Olds engine. It will use the bellhousing pattern used by all modern Buick/Olds/Pontiac engines (BOP-pattern).
It might require new mounts, but the Olds engine has mounting provisions about where the AMC engine does. I'm considering dropping in a built 403 Olds motor into my Cherokee (I've got the built motor basically doing nothing, and a spare BOP TH400 and spare AMC TH400 w/QT output just sitting there, begging to jump in there), and have been considering the logistics of the swap. I'll have to actually have the engines side-by-side to make a valid comparison, though.
<BLOCKQUOTE>quote:</font><HR>How will I wire up the thing for the glow plug light? Will I need the wiring system out of the car too? If so will all my gauges work still?<HR></BLOCKQUOTE>
Gauges would be the least of your worries. It sounds like a gas motor, though, so that shouldn't be a concern.
<BLOCKQUOTE>quote:</font><HR>Will my NP208 transfer-case bolt up to the TH400? Will I need the Chevy NP208 adapter to make that part work? I need to keep it driver's side drop or I'd use the chevy's 208 case that's still attached to the TH400.<HR></BLOCKQUOTE>
The '88 and up Chevys used a driver's-side drop transfer-case, which should bolt up to the TH400 you end up using.
<BLOCKQUOTE>quote:</font><HR>How good are the 350 Diesels? when it was in the car it felt pretty torquey, and it was front wheel drive! I bet with my 3.73's track lock and TH400, it should sing!<HR></BLOCKQUOTE>
If it felt powerful, it wasn't a diesel! http://www.cs.colostate.edu/~zeimet/ubb/wink.gif
The Olds motors are great- high-nickel blocks, forged rods, good-breathing heads. If it's a diesel-block'd gasoline conversion, then it's much stouter than any other small-block you'll come across. The diesel blocks were the basis of Olds' NASCAR engine program in the 1980's, and were the block of choice for the pre-mountain-motor Pro Stock Olds entries. So it would handle any abuse you could throw it in your FSJ.
<BLOCKQUOTE>quote:</font><HR>I'd like to keep the truck as un-bastardized as possible and just drop this motor/tranny in without having to fool with too many things.<HR></BLOCKQUOTE>
Well, that's not going to happen... http://www.cs.colostate.edu/~zeimet/ubb/wink.gif
Figure on custom engine mounts and exhaust, new transmission and transfer case, rewiring of the engine compartment (starter is on the other side, you'll be deleting the Motorcraft ignition box and wiring, etc), swapping to a radiator with outlets opposite where they are (the bottom hose from the water-pump to the radiator is passenger-side on the Olds motor), re-routing fuel-lines (of course, the fuel-pump is also on the passenger side in the Olds), converting to a pre-'80 shifter linkage for the TH400, adjusting driveshaft length (if necessary), and a bunch of other little things that you'll discover in the process.
So it's not just a "drop-in".
Did I mention that the AMC 360 is a good motor, if it's built right? The above conversion can probably be done for less than $2000, if you do most of the work yourself. Or you can build a pretty reliable 360 for that amount as well.
Bob Barry<UL TYPE=SQUARE>* '78 Cherokee 4-door
* '88 Grand Wagoneer[/list]http://studentweb.providence.edu/~rbarry/wheels/
08-11-2000, 02:15 AM
I would say that the olds 350 diesel is not a great idea, for all of the aforementioned reasons, and I hate 6.2 liter diesels, but if I had to choose between the 350 or a 6.2, I would go with a 6.2, but if you want, like they mentioned it is a great engine as a gas burner, but real diesels have much more beef, and the swapping in of the fuel system would be a fat hairy b**ch, but it could be done, but its just like lowering a truck, why do it when it ain' gonna be worth a crap, except as a bottomless money sucker, but anyway do whatever you think is right for you, but I would go either gas conversion or rebuild the 360.
1973 J-4000 3602v ,TH-400
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