What engine would be the best for performance mods? Buying a new (to me) diesel

[bigjoe25]

LONG POST! You have been warned!

Okay here we go, I got bit by the diesel bug recently and I'm looking for a comfortable cruiser, reliable, good MPG, and somewhat quick (I consider 14.0 and under in the 1/4 mile quick enough)

After doing research I'm finding these old benz can fit all the criteria. I also MUST have an automatic, and for everyone telling me to buy a newer VW, I hear their automatic trans in the diesel cars are junk. It's going to be tough as there are no true bolt on performance parts like the VW's and most things will have to be custom or shipped to Europe to be modded but that doesn't scare me.

For my automotive background I've done some nifty things before. For example, I built a 92 eagle talon up to 600+hp to all four wheels, ran 10.8@130 in the 1/4 mile, no nitrous, full interior, street tires, stock suspension. Got kicked off the track due to not having a roll cage. I've also done some other things such drop a chevy 350 into an old Rx7, supercharged a 86 944 N/A, and built a twin-engined dodge shadow AWD.

So here we go! I have four cars around me to chose from, and I've done research but I'm still undecided. Strangely they all have white exterior color except for one. I'm going to list the cars I'm looking at, and in your opinion which one should I get baring the , mileage, exterior/interior condition, and driving condition is all the same. These cars are all within a 5 minute to 2 hour drive away.

1985 300CD coupe. Price: 2500 cash, dealer. No payment options. 5 minute drive away
Pros:
Complete car-fax history report with tons of maintenance records. Cylinder head with all gaskets and timing chain stuff done in 2012.
Cool looking B-pillarless coupe with all the windows down and sunroof open
OM617 is dead solid reliable
Only car with cloth interior, which is actually a plus in my book.
Did I mention it's freakin' cool looking, timeless classic.
Cons:
2nd slowest of the 4 cars.
Not as much performance options as the other engines
W123 chassis is dated, hard to do suspension mods and find aftermarket wheels. Best I can find is the CLK320 lightweight wheels, and they're only 205 wide. Fine for cruising and light weight for MPG, bad for any serious handling.
Costs the most by a good $700-$1000 premium over the other private owner cars and it's cash only. It's at a dealership so this could explain it.
Has been repainted, the front part of the car looks shiny while the rear looks semi-dull. It's a 10 footer car for paint. Car fax is clean though, I was thinking it was in a fender bender but I guess not.
I'm a 6'5" 265lbs man. I hear the coupes have the worst headroom out of all the cars I've listed, and the backseat is worthless.
I haven't driven this car yet, I've only seen it on the dealership lot despite only being a 5 minute drive away. I just recently found it today.


1986 300 SDL Price: 1500 cash, private dealer.
Pros:
It's a bigger car so I can stretch out on long distance drives.
It's a long chassis, so people can fit in the back easy even with my seat all the way back.
OM603 is arguably the best for performance mods.
I've seen and driven this car in person and it runs great.
It's the cheapest car and I bet he would come down lower as he just bought a new truck and has no need for this car.
Cons:
It's a BIG car. It's a pro and con, nice for the highway, crappy for the city and parking.
Being so big and heavy, it's the slowest car on the list by despite having the most power.
It needs TLC. Runs fine, stops fine, but interior and exterior need work. Little bit of surface rust on the front bumper area, unsure about the under body. Seats are 7/10 which is good, but headliner is trashed, and has cracks in the dash.
Needs a front ball joint/suspension work, and in my experience this can be expensive to replace. Not to mention, I am unsure if it has traditional rear suspension or the self-leveling type. I want to avoid the self-leveling type!
Again on the suspension there is little to no aftermarket, 20+ hour job to replace sway bars, and even though there ARE good aftermarket wheels, they're EXPENSIVE (think $1,000 per wheel not including tires)
It would be much less of a sporty car which is what I'm shooting for.
I am worried about the #14 cylinder heads. Unsure what ones are on it.
Worried some more because it may be a money pit, that's why the initial purchase price is so low.

1993 300d 2.5 turbo. Price: 1700, private owner. is her best offer so far so price = $1701+
Pros:
Interior and exterior is mint, or so it LOOKS like and the guy says
Has receipts for all maintenance dating back to 1999
Suspension wise, has the most aftermarket to make it a great handling sporty car. Also being a newer car, can find some sweet AMG wheels that fit on it.
This is the lightest car, despise being a sedan vs the W123 coupe.
The 2.5 turbo sounds like a good engine. There are mods to work with it, but not as much power compared to the OM603 stock for stock.
Best MPG out of the three.
It's REALLY not that expensive, especially if i can get it under 2000. I'm talking less than 1/2 blue book value.
Cons:
I haven't seen or driven it in person. It's a good 2 and a half hour drive away. I am afraid it could be a total lemon.
I haven't researched the 2.5 turbo a lot. I am unsure of it's reliability compared to the other two engines.
Being the big and tall guy I am, it's really a 3-seater car. My front seat would have to be all the way back and there isn't going to be anyone sitting behind me.


THERE IS ANOTHER OPTION which I may shoot for! There is 1987 300D turbo near me, about a 45 minute drive away. This is my ideal platform for performance! It's at a dealership and....they seem to know what they got. The list price is......5,500! The thing is though they finance. $500 down and I could get away with as low as $150 bucks a month. The thing is, if I were to finance I would rather have a w211 car, but there are no CDI's around me at dealerships within 5 hour drives. I also don't want a W210 because I hear bad things about the electronics and rust issues.

[Skid Row Joe]

Find an 05/06 E320 CDI in your price range. There was one LINKED TO here with a clean Carfax a month ago that went in the $3K to $4Ks. They need few mods - they're already fast.

[mytmousemalibu]

Personally, I love the W124's. I love my 87' 300D, I'm going to drive that car till it falls apart! Of course it came with the OM603, a very good engine for the most part. They do have their quirks. Unfortunately, the biggest drawback is the old #14 head which mine fell victim to. You will need to check because many were replaced and the one your looking at might not have one but even if it does, thats still not a deal breaker and can be used as a bargaining chip. As good as the OM603 is, arguably the best of the Mercedes diesels is the venerable OM606, especially when it comes to performance. Its the same basic architecture as the 603 but it has a much better 24v cylinder head with a centrally mounted injector/pre-chamber. The 603 is capable of very good performance but with all things the same stuck on a 606, it will make more power. The 606 really doesn't have any common issues apart from some fuel system bits that are known to leak on the turboed units in W210, etc. You can get a W124 with the 606 in the E300 model but they are all naturally aspirated, they never came with a turbo 606. Thats the hot ticket swap for a superturbo W124, to swap in a 606.910/606.962 and ditch the electronic controlled pump to the full mechanical pump off a 603 or the N/A 606. That is exactly what I am in the process of doing to mine. I sourced a 606.962 out of a wrecked 99' E300D and building it. Chronicle of my OM606 swap!

For what you want, the W124/OM603 would suit you pretty well. You can get the power you want, they have decent room (i'm 6'1"/215lbs), I fit comfortably. There are options for suspension upgrades, albeit can be pricey. And plenty of options for wheels and not going to really cost you more than aftermarket wheels on most other vehicles. The 2.5 Turbo is the same basic W124 chassis but with an OM602, the 5 cylinder brother to the 603. I don't know a lot about them but I don't believe they have any head issues. Going to have to push it a little harder to get the same performance but again, a tad lighter too.

Recommend checking them over with a fine tooth comb. Look them over well for rust too. The $5500 for the 300D is way too much IMHO. It had better be almost brand new and a #22 head on it for that kind of money and still too much.

Don't get me wrong, I love the older cars, i would LOVE to have a 300CD. Love the old OM61X engines too, very rugged, dependable and long lasting. Dieselmeken is now doing the MW pumps for these older engines now so its still a viable option. Harder to get power from though. I would really like a clean W124 coupe to stick my 606 in! I also love the big W126 cars. Plush and comfy cruisers but that weight and size hamper your performance goals. For your goal of 14.0 qt. mile or less, with a W124/603 turbo, your going have to run a bigger injection pump. With everything in top order, pump timing correct, no chain stretch, pump adjusted all the way, fresh injectors, wastegate/boost set for max efficient psi, synthetic oil, clean filters, free flowing exhaust (no cat), pull extra weight (spare, jack, etc) and good atmospheric conditions, its probably a 16ish sec car if you are lucky. Stick a 7.5mm pump on it and a better turbo with the above and your there.

Welcome to the forum BTW!

[grease lightnig]

These are the way to go. Keith at GDE tuning can give it a tune (for a price) and help with even more power upgrades. I find it easier to work on than all of the older ones. The transmissions are good for more power if you figure out how to get there.

Downfall is they are much more money to start with. If there is not one in your area find one far away fly in and drive it home. It will impress.

[oldsinner111]

I would stick with a cast iron block,with steel sleves

[GregMN]

For not much money, but will keep you occupied for a while:
Put a 606 into a W201 with a manual.

For more money, almost no time involved:
Get a W211 and have GDE write a tune for you.

Mercedes CDI Shopping Spreadsheet

[BillGrissom]

14 sec in the 1/4 mile is pretty fast. Until recently, new Corvettes weren't much better than that from the factory. Even there, you need good tires to connect. It seems a diesel sedan w/ seating for 5 is a totally different world. There are a few who go performance w/ diesels. Look up youtube videos. There are some in Finland and Sweden who mod the injection pumps for more flow and get power to spin the tires. Downside is they pour out thick clouds of black smoke, as do diesels in tractor-pull competitions and such. Otherwise, not much in performance mod's for older M-B diesels, at least at your benchmark.

[biopete]

Originally Posted by oldsinner111

I would stick with a cast iron block,with steel sleves

Fitting for an old sinner

[biopete]

Pretty much what everyone said. For the money 606 turbo is best bang for buck and the w210 is the biggest body but still pretty light. Good for a tall person. Much head room. I got a nice 1999 i'd sell. Pm if interested. One day I'll post a list of all the good diesels I got or my friends have for sale. They won't be steals but they will be tried and true and not a used car gamble.

[biopete]

Just had a thought. Put a 606 turbo in a 1970-1980s r107 sl. Like this guy. Not "another" diesel 107!!

That is what i want for a daily commuter.

[babymog]

Agree with much of the above.

It depends on the budget, and whether you tinker for fun. The 124/603 turbo is a nice start on a budget, can accumulate parts to make it snort, but this would be an '87 which has a soggy suspension and few of the later 124 refinements. The later 5-cylinder cars were okay, but the loss of one cylinder isn't the direction you're going. last 124 with the 606na? Not a hot performer either, and adding power to a non-turbo engine is difficult to do well. You would get the latest body and interior upgrades however.

I'd look for a nice 210/606turbo for about $5k. If the body is straight you can fix minor problems by buying parts from the many E320/E430s in the boneyards. You'll put a fair amount of money in an '87 300D to make it as quick as the 98/99 is stock.

Bigger budget? Move up to a Cdi. Again faster out of the box. Less to tinker with, but better stock.

I'm a 124 fan, but I did mine for the nostalgia and for the enjoyment of the project, it's what makes a hobby. I also have some professional history as an Engineer in the 124. If not, I would have started with a 210 instead, took half of my mods just to get to the performance level of the '99 E300 Turbo and I lost track of my expenses in this car long ago.

[oldsinner111]

aluminum blocks suck.Put a cummin's in it.

[BenzBUSY]

Personally BIG Joe....You may not find in MB what you look for. I represent a BIG company in TEXAS......For 50 million dollars, we will sell you...like a crook...tomorrow....