With gas prices going up again has anybody thought about converting a Slant to a diesel. I seem to remember that Chrysler played with a 225 diesel back in the 70's but I'm not sure. A Slant diesel sure could sell today if it got around 40MPH!!

I would hope it could get better than 40 mph! We know what you meant.

Chrysler did have a diesel slant six program in the 70s and 80s, but it was dropped. I would be very interested in knwoing how to do a slant six diesel conversion, especially since biodiesel is really getting popular here in the Puget Sound.

Lets see, special pistons and rings, glow plugs instead of spark plugs, fuel injection has already been accomplished with home-brewed fuel rails and machining, cutting the block and head to get the 20+:1 compression necessary, new cam design?, new gas tank, new fuel lines and electric pump, I guess the distributor could become the trigger for a mechanical fuel injection system?

It certainly sounds doable, the main drawback I see is getting the high compression ratio out of the stock cylinder head. Turbo diesel would really be cool!

Heck, I have a spare slant six on a stand in my garage. I would be willing to play guinea pig! I know nothing about diesel technology though.

I keep hearing that Chrysler played with dieselizing the slant, but I sure don't remember anything from back then. What Chrysler DID do was offer an inline-6 diesel engine in full-sizepickups. It was made by either Nissan or Mitsubishi, I forget which. A real slow pig and a smoker, but with diesel economy and good reliability. They also offered a Mitsubishi 4-cylinder diesel in the Mitsubhshi-built D-50 pickup, IIRC.

Someone said that EFI has "been done" for a slant six... wrong. It hasn't been done the way it would need to be (direct high-pressure injection) for a diesel. Diesels don't run with multi-port FI, only with direct (no prechamber) injection, or indirect (through a prechamber with a glow-plug) injection. Both require injection pumps that produce very high pressures since the fuel is injected into the chamber AFTER the compression stroke has occurred.

I would guess that the slant-6 bottom end would be strong enough to take the pounding that a diesel top-end would give it, but at a pretty major de-rating compared to the power it puts out as a gasoline engine. It would probably be a stretch to get more than 90-120 horses out of it in diesel form, if that much. And that assumes a completely new head design which would accept injectors and provide enough compression- figure a bare minumum of 13:1 for a direct-injection turbodiesel layout, more like 18:1 bare minimum for an indirect-injection normally aspirated diesel.

All in all, a pretty tall order.

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Practically speaking, this is not a "doable" conversion. The factory diesel-225 program had a huge amount of project-specific engineering. It wasn't a halfåssed make-work deal like GM's Olds 350 dieselization fiasco. High-pressure injection system, new rods, new pistons, new head, new manifolding, pretty sure a 7-bearing crank and matching block...about all it shared with the gasoline 225 was the displacement and the slant angle!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

This is almost off topic, but interesting. My Father in law has a Dart that is diesel powered. I have seen and driven the car and it was a bit of a mystery who put it together. It was claimed to be a factory car by the person he bought it from. The emission info plate was for a 318 but most of the engine brackets and mounts appeared to be Mopar. The only odd looking part is the radiator hose routing. It is a inline six and if I remember right is a nissan. There is a factory looking adapter plate connecting it to a Torque Flite. We figured it was an aftermarket conversion from the early seventies and that someone used as many factory parts from other applications as possible and must have manufactured the trans adapter. It must just be one of the setups from the pickup. It is a real slug and very noisy. An average person could outrun it on foot for about the first fifty yards.

Any chance his diesel Dart is a '73 or so? I have (or maybe "had") a 1973 Popular Mechanics or Popular Science road test of the Nissan diesel aftermarket conversion you describe. The one they tested was in a '73 Dart Sport. Their findings matched yours: Loud, unreasonably slow, too hard to start when cold, generally difficult and obnoxious to live with, but returned pretty good MPGs.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Unless you put some kind of forced induction system on them diesels are pigs. My uncle used to have a Datsun pickup that was a diesel. It would top out at around 50 but got over 40 MPG.

Tell me a little about this GM-Olds 350 Diesel. I did not know these things existed.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

Thanks for that tidbit Dan. I am pretty sure the diesel Dart is a 73. I'll have to find out for sure in the next few days. I'll have to see if I can look up that article, I'm sure he would be interested.

Not too much more to tell...GM did a slapdash, half-baked job of "dieselizing" the Oldsmobile 350 V8 engine and offered it in a whole slew of GM B-body passenger cars from '78 to '83 or so. Caprices, Cadillacs, Delta 88s, etc. It was a hideously bad engine. It broke frequently and expensively and without warning. It emitted great stinking clouds of black smoke. It was far too noisy and rough. And it was put in marginal cars with super-weak transmissions. It arguably did more to turn North Americans off diesel engines than anything else.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

if you want a cheap way to win circle track races, buy one of those cars with the diesel still in it....get a set of heads, intake, and distributor from a gasoline car.

run AV gas in the thing and hold on...i know of several guys that did this for a whole season in the beater stock class with great success and minimal outlay of cash....shoot, i may do it this next season.

sb

Wow, I'm getting old. One of the automotive biggest boondoggles of my lifetime, and now people don't even know about it! Does "V-8-6-4" ring a bell, or is that one forgotten in the mists of the 80s too? Vega? Pinto? Mustang-II?

OK, this is way off topic, but since you asked:

It was just what it sounds like. GM took the basic Oldsmobile 455 bottom end, and fitted it out for diesel operation with different heads, pistons, rods, etc. and used the crank and block deck height dimensions from the Olds 350 (the 455 and 350 were the same basic block, but the 455 had much bigger bearings that suited a diesel better). The Olds bottom end was actually up to the task- it was by far the strongest GM engine and most suited to dieselization. The real problem is that they didn't dieselize the CAR around it. It used a gasoline type fuel sytem with minimal filtering, NO water traps, etc. And they never made much effort (initially) to educate people that a diesel engine DEMANDS much more attention to fuel and air filters than a gasoline engine- in fact GM tried to make it seem like "just another car" that didn't need any special care, which was far from the truth.

The result was that the injection pumps suffered tremendously- water contamination, grit in the pumps and injectors, etc. etc. When that happens to a diesel, it affects the whole engine because you can get (for example) ONE cylinder that is getting a huge slug of fuel while all the others are at idle, so that one cylinder constantly sees super-high combustion pressures. Essentially one cylinder carries the whole engine up to a point. That means its corresponding rod bearing gets pounded, the crank gets abused, the cylinder head bolts get stretched, piston cracks, etc. etc. etc. Combine that with a cylinder head bolt pattern not *really* meant for diesel pressures, and a bottom end that is strong, but not to the degree that dedicated diesel bottom ends are, and you have engines failing by the hundreds. It was a "perfect storm" of an engine that was 'OK but not great' combined with a fuel system that would have seriously damaged pretty much ANY diesel engine and was certain death to a marginal one.

To be totally honest, toward the very end of production they got the thing working really well for what it was- a low-output normally aspirated diesel that was loud, smoky, and slow but very economical. Pretty much every aspect of the engine got upgraded. The later factory engines and the "Goodwrench" replacement engines had new head bolts, gaskets, maybe even new head castings and a revised block casting, stronger internal parts, added fuel filters, improved injection pumps, and a lot of other details that should have been there from the start. I had an office-mate in college who had one in an Olds 88 (the big land yacht) and took it ALL over the country with never a hitch, and on a college students budget. It just ran and ran and ran... but it WAS a "Goodwrench" labelled replacement engine with all those upgrades. The original engine blew up long before he even got the car as a used car.

<looking around to see if this is safe to admit...>

If an Olds Diesel car that hadn't already been grenaded fell into my lap right now, I'd be seriously tempted to play with it for a while, or maybe even transplant the drivetrain into a Mopar so I wouldn't have to live with a crappy GM chassis. I'll bet you anything that I could get a lot of good service out of one, as could anyone who would be willing to take care of it and not push it beyond its limits. That said, I have no idea what the parts availability is like these days. I LITERALLY see more '64 Valiants on the road than I do any model of car that still has an Olds 350 diesel. Heck, I rarely even see a GM 6.2 liter diesel pickup, and that was a far, far more durable engine (built by Detroit Diesel). But when the Ford/Navistar 7.3L diesel truck came out in the mid 80s, it was SO much better even in its original normally-aspirated form that it pretty much blew the 6.2 and 350 into oblivion, and of course the Cummins B5.9 powered Dodge Ram and Powerstroke version of the Ford/Navistar reduced sales of the 6.2 and the later 6.5 to a bare trickle and effectively took GM out of the diesel pickup game until the Duramax came along. Even the used market for them dried up and they all but disappeared. There's no way that a normally aspirated diesel can really compete with a turbodiesel. NA diesels are fine for stationary applications and tractors, but they just don't hack it where a wider operating RPM range is needed.

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Well, I somewhat disagree that it was so much the ENGINE as the fuel system... but the result was the same.

And your point about the transmission is VERY valid- the GM TH250 was a weakling, and its weaknesses were aggravated behind an engine that produced a lot of torque at low RPM. And the later TH200R4 was as putrid in its early years as the Chrysler A-604 was. To compound things, when they did fail and got rebuilt, a lot of shops would slap in the torque convertors intended for GASOLINE engines, which were substantially different in stall speed and other characteristics than the one the diesel really needed. The same problem happened with the 6.2L diesel and the 700R4 transmission that went with it- a high-stall convertor and shift kit just don't play well with a diesel!

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The main problem that I remember about the Olds diesel was the oil filter was too small and the bearings usually gave up from the crap in the oil.

HT4100?
My recollection is that washing the engine as one might do at a coin-operated car wash was a surefire recipe for a dead-and-buried fuel injector pump, too. Not sure how/why.
Yeah, the beancounters were finally shouted down by the engineers and a "WATER IN FUEL" warning light was added to the dashboard.
It's tough to fall off the floor.
*red and blue flashing CSRs in your rearview, DIN 'hee-haw-hee-haw' siren just to annoy you*

You! In the '66 Dodge! Pull over!

*step, step, Step, Step, STEP*

Guess you didn't see me when you looked around to see if it was safe to admit. Gon' hafta impound your vee-hicle. Or, just never let you hear the end of this...yer choice.


Me either. Given that supply usually is linked to demand, though...!
Same here, and I live in Toronto, which is a brutally car-hostile place. (That said, I'm in Seattle right now, and it's always really interesting to get out of the rust belt and see what kinds of cars survive. Every Volvo 240 ever made is running around in perfect rust-free condition up here! Lots of VW vans, which anywhere else tend to rust out if you sneeze at them. I'm even seeing the odd early-'70s Honda Civic and a couple Subarus from the 1980s! And I've seen five or six different A-bodies so far in five days, which is more than I've seen in Toronto all year...)
Oh, the kind that sounds like a permanently-unbalanced washing machine at idle.
You misspelled "less bad".
The one that sounds like it has metallurgical diarrhea at idle.
Which, from my limited experience, is a very nice engine to drive and live with.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Firestone 500 tires

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes