I heard that the diesel olds/buicks/cadillac/anyone else? engine could be converted to gasoline, and since the block is heavier duty than a regular 350 gas block, it'd make a good race block. Is this true? -matt
you can do it I wouldnt say its a good race block, but you can convert them. my brother did it with a diesel block and heads from a 75 cadillac seville. nice cam and aluminum intake in a cutlass. didnt run too bad but ya cant rev em very high becasue the rotating assembly of the diesel if ya keep it stock is too heavy. you also have to grind or machine the boss off the block where the injection pump connects.
If you use the stock, heavy diesel rotating assembly, then no it probably wouldn't make a good race engine. But if you're rebuilding your engine anyways, then you can use just the block and throw in lighter parts. There are no off-the-shelf piston/rod/crank combinations, but it can be done with a BBO 400 crank cut down for BBC rods and custom pistons. There are guys who use the diesel block for race engines. They say that it has more metal in key areas, like the main webbing, than other olds blocks and can be bored out to around 4.25" (stock 350 bore is 4.057", I think typical gas 350's can go to about 4.125"). Go to RealOldsPower.com and check out the forums. I'm sure you'll find the answer there.
The 'DX' Olds 350" diesel blocks can be bored and stroked up to 454"!!! You can bore them just shy of .200" and stroke them with the 425" crank (with the counter weights turned down). There are plenty of MAX effort Olds guys running these blocks!!:TU: :TU:
Actually most of the fastest oldsmobiles in the country either us the nascar small blocks or the 350 DX diesel block. To make these run they require custom parts and most use Batten heads
the owner of the ROP site has a digger with the 350 nascar block has a best 60 ft time of 1.02 this is twin turbocharged injected and is one nasty engine. Another member is into the 7s with his so yes indeed they make a heck of a race engine for a heck of a price tag
so it's true! And the blcoks aen't worth much since that diesel is junk with only 200 ft/lbs and less power than my Saturn(I hate to say that, but it's true, even though my Satty does a good job at keeping every stock or riced civic below the Si in the mirror.)
diesels run some pretty high compression. you'll have to do some thing to remove some of it. I don't know were the compression comes from on those motors(i.e piston , small chambers).
in a diesel, other than a "precombustion chamber" on some diesels, there is no combustion chamber in the head. On the olds diesel, the pistons look like regular notched pistons. On the Cummins diesels they had in my diesel class last year, the combustion chamber was INSIDE the piston, so I guess you could call it a "really really deep dish piston".
Having been one of the unfortunate ones to actually own a GM product that had that crappy diesel engine, and being too darn poor at the time to have someone else work on it, here's a bit of info on that thing. As a diesel, it sucked. The stock head bolts didn't keep the heads from walking around on the block which broke head bolts with great regularity and tore up head gaskets as you can probably imagine. The injector pumps were a notoriously weak point with these engines. I went through three in about 50k miles. The earlier versions of the diesel had thin-wall mild steel oil cooler lines that were approximately 7/16" ID. Think about that a minute. The lines were fairly stiff, ran hot oil, were constantly being flexed back and forth and subjected to some pretty severe vibrations. I went through so many sets I quit counting. I finally got tired of replacing them (no easy task, let me assure you) and changed out to a set from a 1-ton Chevy truck that were braided nylon with the right size connectors already on them. The diesel was very sensitive to clean air filters and clean oil. Let one go for an extra 1k between changes too often and the rocker arm pivots would be trash within about 20k miles. Now, the funny part is that anybody that is familiar with the small block Olds is way more familiar with the diesel than they think. Practically the same engine. I don't remember who it was, but back when these things were fairly new and common, an aftermarket company was making kits that let you put gasoline cams, heads and intakes on the diesel block and, Presto Chango, you now had a tough as nails gasoline 350 Olds. As I remember, there was an issue of plugging the hole in the front of the block where the injector pump used to go. That pump was cam driven by a gear between the # 2 & 3 cylinder cam lobes. There was actually a bit more to it such as fuel pumps, timing chain sets, etc. The high compression needed for this to function as a diesel came from the heads. There was almost not combustion chamber at all. There was a small chamber where the injector and the glow plug both fit. Taking out the glow plug and inserting a really thin drift allowed you to "press" out the bottom of the chamber after the heads were off. I did this to enable me to properly cleam up the heads prior to reinstallation on mine. Oh, the intake valve would build up carbon so thick, you just wouldn't believe it. With no exaggeration, I took over 2 dry cups full of pure carbon off the back of my intake valves. More than that from a higher milage car. The starter for these engines had a cast iron nose as the regular aluminum nose would not stand up to the torque required to spin through the compression these things made. Even then, the nose had a bad habit of cracking. A really cool thing that GM did for everyone that ever wanted to run parallel batteries was to make a very specific set of battery cables to do just that. Also, the oil cooler is fed from the bolt-on oil filter boss. That means that ANY Olds can benefit from a factory appearing oil cooler that has the in and out lines already pointed in the right direction and properly engineered to minimize oil pressure drops. Over all, these engines can make dynamite race motors. Just as with any other project like this, do your homework, talk to someone that has done it and to some of the suppliers such as Dick Miller, Joe Mondello, etc. I just finally got tired of messing with mine and picked up a running 350 gas motor. Other than ignition and fuel system, this was literally a direct bolt-in replacement. Same exhaust manifolds, motor mounts, trans connections, heck, even the air cleaner was the right size for the quadrajet! Easiest one I ever did.
I think the olds 350 diesel ran 22.0 compression ratio, but that was about a year ago I rebuilt one in diesel class (since then i moved to auto collision and got a "smokers cough" (I don't smoke), and so to avoid the dust and not having to remove 400 parts just to do a plug change on a new car, I moved to accounting.) Is all olds 350 (gasoline) engines essentially the same? In my dyno 2000 program there's 2 (two) Buick 350s. That confuses me.
I just noticed this thread on the 350 diesel and will probably open up a can of worms by saying something but here goes. That particular engine design was not all that bad and yes it caused much grief for owners and GM. I did all the warranty work on these engines in my area from late '77- '83 when I left the dealership. I have to say that most of the catastrophic failures(head gskts/bolts,cranks,and main webs) were actually due to incredibly high cylinder pressures(dynamic pressure) being created by the ridiculously high final drive ratios those vehicles of the time had(pass cars-2.23:1 pu-2.56:1-with 3.40:1 being the lowest available by special order) and then add the overdrive to make the problem even worse.Diesel engines do not tolerate being lugged! Starting in about '81 I began installing 3.73 - 4.56 gear sets behind them and all but the fuel problems went away. That was eventually resolved with a spring type drive damper in the injection pump. This seemed to be a case where the engine developers had no communication with the power train people! Now you can rip awayp
I love diesels (for truck or economy applications) - I work at a dodge dealership in the service dept. (as a porter; I pull up cars for people and put the plastic seat covers in them). The diesel fumes wake me up, and driving them- I can feel all that torque and the sound of the turbo winding up is incredible. Too bad I'm not hauling a 30" 5th wheel behind some of those. That new Cummins has 600ft. lbs.! Wonder when people will start coming in with broken axles...:Brow:
I know this is an old thread... But most Olds Diesel 350's that are converted are pushing 442ci and can make massive amounts of HP... Hot Rod (Or Car Craft) did a test of X pipe VS H Pipe VS Open headers on one... and it gave most of the specs on the engine, like what crank to use, what heads were being used, etc. Made a bunch of power and ran consistent 10's in an a-Body Cutlass
yea, 442 ci I think is the biggest you can make 'em, but it's enough to kill all of the Honduh DX SiR Type S Type R powered by Mitusbishi K&N edition Civic.
