Anyone else currently own a 78-85 Cadillac diesel?

Started by TJ Hopland, December 31, 2014, 09:46:50 PM

Previous topic - Next topic

TJ Hopland

It made a lot of sense to make things the same.  Using the same 'tin' and bolt on accessories likely saved them tons.  If they were more or less the same on the outside it would require less changes to install them in the cars.   By that time I think every car but the Corvette already had an Oldsmobile engine option.   Even the 6.2 diesel that came out in 82 was designed to replace a gas engine.   Basic dimensions were similar.   Same bellhousing.  Exhaust manifold dumps in the same spots, stuff like that.   

Over all the concept worked well for the Olds but one major area they should not have done that was the head bolt design.  That also came directly from the gas engine.  Most diesels have at least 4 bolts per cylinder.  The olds had 10 per head, a typical 4 cylinder diesel head would have at least 18.   

I imagine on paper and even 'in the lab' 10 was enough but in the real world of 1980 diesel that design did not leave any margin for error (or abuse) including the quality and spec of the original bolts they apparently used.   If they would have come up with a better head clamping design originally or even with their first major redesign around 80 the outcome would have likely been a lot different.   The transverse V6's that came out around 83 did have a much better design.   I would imagine they didn't bother to put it on the 5.7 because after 85 there were not going to be many cars that would want a 5.7, remember most of the RWD cars were gone by 87.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Big Apple Caddy

In the early 1980s, Cadillac was still playing up resale value advantages of the diesels.  Attached is part of a 1982 brochure.  It wouldn't be too long, however, before Cadillac and other GM passenger car diesels would be seeing major value deductions!

James Landi

WOW-- the "LAST REASON"--- gets my conspiratorial nerves on end! Did the marketing department already know that this model was the least valuable among the fleet?  I wish to mention Dr. Welsh's commentary in previous posts here as well.  The GM engineers were struggling with block failures...as he mentions, cracks in the castings that developed overtime. I have read many posts about the poor quality of available diesel, the lack of water separator filters in passenger vehicles, and the blown gaskets due to hydrolock... but aluminum durability appears to be an issue as Dr. Welsh cites, and does it not continue to be an issues for the next three and a half decades ?

Eric DeVirgilis CLC# 8621

#23
Depending upon when that ad copy was written, they would have been correct - at least according to NADA guide and other so-called blue book publications.

I seem to remember the "Add for Diesel" adjustment as late as 1981 or 1982; within a very short time the "Add" became "Deduct for Diesel -$500 and shortly after that it became "Deduct 50% of Trade In Value for Diesel."

Say what you will but the fact is that there is a definite "cult" following for the once-maligned power plant today and you'll see no shortage of interest/activity on GM diesel powered cars when they do appear on eBay.
A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

Big Apple Caddy

Quote from: James Landi on January 05, 2015, 01:07:45 PM
WOW-- the "LAST REASON"--- gets my conspiratorial nerves on end!

It was an interesting choice of words given how things turned out.  Perhaps there was an "inside joke" going on there.

There were already known and notable problems with the diesels by September 1981 but I guess it took a little while longer for the resale market to reflect these issues.

I believe 1981 was the sales peak for the GM passenger car diesels but with falling gasoline prices, more widely known reliability issues, etc. the market for these engines quickly declined over the next few years.

Big Apple Caddy

Quote from: ericdev on January 05, 2015, 01:21:36 PM
Say what you will but the fact is that there is a definite "cult" following for the once-maligned power plant today and you'll see no shortage of interest/activity on GM diesel powered cars when they do appear on eBay.

Very true.

Dr. John T. Welch

The marketing of the VIN code L 5.7L diesel powered vehicles was problematic.  Because this was a centrally mandated cross divisional powertrain option (meaning a forced factory option in addition to all the divisions' established standard and  optional  gasoline engines) and each division had its own advertising agency, the marketing and advertising came in many flavors.  Suddenly, each division had to fit this" new child on the block" into its own demographic and established tag lines for the overall benefit of the whole CAFE. This was decidedly new territory for GM and was difficult to handle.  Add  to that the woes of early mechanical failure and customer disappointment;  this inflicted some damage on all the brands.

A major priority of product planning and engineering was to have the diesel experience be" transparent" to the owner/operator. The esthetics and dynamics of vehicle operation were to mimic as close as possible the gasoline powered versions. The only differences perceptible to the user were  to be the brief glow plug heat time before start and fueling from a different pump at the filling station. Otherwise, it was to be same as, same as, and "be sure to visit your local authorized GM dealer for regularly scheduled maintenance and service".  It didn't quite work out that way.

The divisions marketed the diesel option as an upsell, and the added cost definitely made it so.  Frequently, the diesel option was included among those of otherwise heavily optioned and accessorized units which drove the total vehicle cost even higher. People didn't like having paid a premium to have such confounding  and repeating problems of operation and reliability in otherwise wonderfully appointed cars, especially during the first 12 to 24 months of use. Many owners could not get away from their 5.7L diesel powered cars fast enough even though they were still under factory warranty and short of lease/purchase contract terminations.

The 6.2L engine family was completely new architecture and shared no cast components with any previous or other engine family. There was major engineering input from Detroit Diesel, and this engine was robust in areas critical for sustaining diesel combustion.  It did use conventional indirect injection employing the Stanadyne Roosamaster pump. This was a very successful diesel engine program and eventually allowed expansion of displacement and turbocharging in the later years.  This product was limited to C/K light,  medium duty  trucks,suvs and vans, cab/chassis conversions and military /civilian versions of Hummers. There were no passenger car installations of the 6.2L family of engines.

The 6.6L Duramax family of engines replaced the 6.2L series and has been very successful in the era of modern diesel emissions compliance.

A casualty of the GM bankruptcy was the 4.5L Duramax.  This is a revolutionary "reverse induction" diesel engine designed from scratch by GM Powertrain.  It was ready to go as an option in the GMT900 platform vehicles until GM had to do the Pelosi political pivot away from pickups and large SUV in order to get the bailout. Google "4.5 Duramax" for details on this astonishing engine from Wards publications.

The newest generation, foreign and domestic,  of passenger and light truck/suv diesel powered vehicles are technical marvels. 

       
John T. Welch
CLC   24277

James Landi

John, 

Interesting that you mention Detroit Diesel in your narrative.  Having owned two large boats, power by 871 Detroits, I became very familiar with these amazing two cycle, mechanically fuel injected, super charged engine platforms.  These engines enjoyed extraordinary long maintenance free service life, and could run up all day at 90 output without straining internal components.  ALas, they pushed unburned hydrocarbons out every pore, and as you clocked thousands of hours, they'd push out amazing clouds of smoke when cold started, much to everyone's discomfort and embarrassment.   GM had several "runs" at early 4 cycle diesels for marine conversions, but they were not reliable.

TJ Hopland

The 6.2 / 6.5 'baby Detroit's' didn't really have much in common with their full size relatives.  They still had to try and keep the size and weight similar to the gas engines they were intending to replace.    Up till the Duramax series GM's diesel philosophy was always more in the direction of economy than power.   There is still a few companies doing marine versions of the 6.5.  Just like in the trucks it was just an alternative to a big block gas engine, basically a bolt in swap.  GM quit making the 6.5 in 2000.  At that time AM General bought the tooling and built their own engine plant primarily to continue supplying the military with the engines.  I think GM continued to buy them for the P series vans/trucks for several years.   I think the more current offerings for GM delivery van type of things are all Isuzu based.     The Duramax is/was a joint effort between GM and Isuzu.  Isuzu has its own line of diesel engines but just like the 5.7 and 6.2 GM wanted something tailored to fit the intended market so that is where the Duramax like came from.   The diesel Forums have been buzzing about the 4.5 for years and as far as I know its still not any closer to production.     

Interestingly about the time of the Duramax project GM bought half of VM Matori who primarily makes smaller diesel engines.   The assumption at the time was that GM was going to expand its diesel offerings world wide but apparently not much happened during the period they owned em.   I believe currently they are fully owned by Fiat.   Chrysler was using Matori diesel engines till the Mercedes deal at which point they switched to Mercedes diesels.   Guessing that deal ended with that partnership so the new Fiat group bought Matori to continue their supply of diesels.   Some non USA markets are primarily diesel so owning and producing your own diesel engine is important.   

I think currently the Cruise is the only GM car you can get in the USA and I think it came mid 14.   I believe all the major manufactures have announced several diesel options for the USA market over the next couple years.    I think Ford and Toyota are the only ones that don't have anything last time I looked.

I looked at the Cruise and just didn't like it.  I didn't find it comfortable or a nice ride.  Also didn't like the options you could get with the diesel.   Other than USA markets there were a lot more options including a wagon they just didn't offer em here. 

If the spread between gas and diesel stays over $1 per gallon that will likely slow down diesel growth here.  Apparently our refineries are tailored to produce mostly gas so with low production and high demand the prices stay high.    Most people don't realize they used diesel every day so most people don't care.    Almost all goods and services move by diesel or a close retaliative jet fuel so everyone is paying for the high prices now.   If more diesel cars got on the road and our refining process don't change I would think things would get even worse.   Guess its like most things these days, we can't win.       
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Eric DeVirgilis CLC# 8621

A bit off topic here but I clearly remember diesel powered cars exhibiting far less rust than their gasoline counterparts.

I even recall discussing this with others who had also witnessed the same phenomenon back in the day. I guess the soot provided some sort of "undercoating" to the body and chassis...

A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

TJ Hopland

Only reason I could think if there would be less rust is you could not get em started or they were in the shop more often than their gas counterparts so they just didn't get the exposure. 

Seal wise there were identical to any other Oldsmobile and not much different than any other V8 of the era so they leak about the same as anything else in the era.   Some leaks like say valve cover gaskets are a lot more expensive labor wise to fix.   Imagine doing the gaskets on a gas engine with solid steel spark plug wires.   Lots more stuff to take off to get to em.   

You did get some soot out the tail pipe but I would think that would only effect things at the back.   Bumpers and truck lids rusted so bad in that era I can't imagine it helping or hurting.   Maybe helped because owners washed the cars more to get the soot off?
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Dr. John T. Welch

Eric,

Thanks for your astute and insightful observations concerning a seeming
corrosion differential  between diesel and gasoline versions of this era GM
vehicles.  I say "seeming" because I have no empirical evidence to reinforce my
similar observations.

I attend many large wholesale, municipal, insurance salvage and private fleet 
auction sales.  Typically, the vehicles are not detailed or otherwise prepped
prior to sale.  It's an "as is where is, what you see is what you get"
experience.  To my eyes, diesel powered passenger cars and light trucks stand
out for reduced corrosion damage.  The differences are subtle but significant. I
have no way to control this observation for the effects of different climates.
In my experience,  Mercedes products are standouts for these comparisons,
especially among the big S series sedans. 

Several acquaintances store diesel powered vehicles at seasonal homes for summer
use. The storage conditions are very favorable, always enclosed and usually
heated,  and the vehicles are properly prepped for protracted periods of non
use. The garage areas where the vehicles are stored always emit the typical
diesel fuel aroma, and over time a very thin fog develops on the interior panes
of the building windows and on all of the glass surfaces of the vehicles. This
film can be wiped with a finger and "felt" as a finger wipes the body
surfaces... bingo, your finger smells of diesel fuel.  The same phenomena can be
observed around the  diesel fueling areas of truck stops. All the pumps, hoses,
towel dispensers, squeegees and card readers have and impart  diesel odor in the
absence of visible liquid fuel.  This is not the case in gasoline dispensing
areas.

I think you are right in that diesel vehicles seem to generate their own "micro
climate" as it relates to corrosion inhibition. Even after 12 months had passed
since I stored a diesel vehicle in my garage, I could still detect a faint
diesel aroma there, and many items stored would leave the slight odor on my
hands after touching them.



John T. Welch
CLC   24277

Eric DeVirgilis CLC# 8621

Thanks John for posting your experience & observations regarding the "non rusty diesel" phenomenon.

Back in the day whenever a relatively clean older GM model was spotted on the road, "Must be a diesel" or "Too bad it's a diesel" was the common refrain.  ;D

It's reassuring to see that I am not the only one on the forum who has witnessed the odd - but decidedly - above average condition of diesel vehicles.
A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

Big Apple Caddy

Quote from: ericdev on January 06, 2015, 11:21:06 AM
A bit off topic here but I clearly remember diesel powered cars exhibiting far less rust than their gasoline counterparts.

I had never heard this theory before.

My experience growing up was that the GM diesels tended to be higher optioned, upper trim models e.g. not a base Cutlass but a loaded Cutlass Brougham, not a base Century but a loaded Century Limited, not a base Bonneville but a loaded Bonneville Brougham, etc.  Not always, but often.  Early on, the diesel engine alone was also a pricey option.  I don't know if historical sales data would support my "loaded up" observation but if so, perhaps the diesel cars were simply taken care of better, stored better, etc. because they were more likely to have had comparatively wealthier owners.

I also think they may have been used less in winter or in snowier climates due to potential cold start issues.

bcroe

Quote from: ericdevCorrect, externals are the same.
Internals are very different - and the diesel weighs 500 lbs more than the gasoline version.

The diesel cars definitely weighed more, I don't know how much.  They had an extra battery, and
a really big starter.  We were just talking about the heavier torsion bars used in the diesel Eldos. 
Fortunately in addition to all the above, the ENGINE was not 500 lb heavier, or the whole scheme
would have been unworkable.  Complete engines or their parts are here for examination. 

The small block Olds got a heavier crank of the identical stroke, and big block mains.  A heavier
timing chain turned both the cam and the injection pump.  This required the front seal to be
moved forward a fraction, and a stronger ring gear met the starter.  The oil pump drive was
identical, but a vacuum pump was plugged in the same position since the HEI wasn't used. 
Cylinder walls though in the identical position, were heavier.  Rods & pistons were redone. 
There was the injection pump instead of a carb, and the heads were totally new.  However they
used the same pattern, so experimenters had no trouble bolting on gasoline heads to creates a
supper strong gas engine out of an old diesel.  Put back the HEI, gas fuel pump, etc.  Bruce Roe

Dr. John T. Welch

In '87 I made a killer oval track Olds 350 using a diesel short block and the big valve 403 heads. Joe Mondello made a billet plug for the injection pump hole in the front of the block. Roller cams for this engine were scarce at that time, but Crower stepped up the the plate  with a roller version of the W-40 stick.  The flat top diesel pistons gave 11.5: 1 compression. We could never kill the engine and nor could the three subsequent owners. The reciprocating assembly was heavy but bulletproof.  The keys were the big block main journals,  the beefy diesel rods, and floating wrist pins. As I said earlier, the vibration harmonics just didn't let this work for durable and reliable diesel combustion.

Sorry for this not being Cadillac, but fun nonetheless.

End of this topic for me.  'Nuff said.  Thanks to everyone.   
John T. Welch
CLC   24277