what motor question

there is a very small 2 door mercedes, probably late 60's early 70's, at a garage i pass while walking my dog. it has been there for about three months and it appears to be pretty heavily scavenged under the hood. for some strange reason i started thinking about whether or not this could be a fun dd.

the question is the drivetrain. i'd like to have something a little more modern for a dd. i dont think anything but an inline 4 would fit, and i'd like to have a manual trans. the hood is low so something short would be best. i'd also like the donor to be affordable (less than 2k for a running example with working ac) preferably fuel injected with a pretty simple/ seperable wiring harness. doesnt need to be a screamer as this isnt a track toy, but it should be able to be fun in a 2500 lb (max) car.

what donor cars would you suggest for these drivetrain needs and why?

Easy answer? BP6/ BP8 from a Miata. Cheap, flexible, blah blah blah. It's always the answer, especially when it makes sense.

Alternatives-
KA24 as used in the 240SX (SR20DET if your're man enough)
FC from Honda S2000 (tough on the budget, but awesome...)

2500 pounds might be a bit optimistic. It's a Benz...they can be deceptively heavy.

KA24 from a 240SX. Drifters throw those things away, it's easy to find 5-speeds for them (which are just T-5s anyway), and you have a nice, easy, 150hp fuel-injected motor with decent torque.

You could also rotary-swap it. That would give you a both height and length short motor that's likely to have a 5-speed behind it. Rotaries are CHEAP to pick up if you're willing to do a rebuild, though I hear the seal kits are expensive.

My immediate thought was a 4A-GE, but RWD 4A-GE cars (i.e. AE86 GTS) are crazy-expensive these days, and 2500 lbs is probably too much for a stock N/A 4A-GE to really be fun If you're willing to convert a FWD motor, you might be able to find a 4A-GZE (supercharged) from an MR2 (yes, yes, MR2 is RWD... it still uses a transverse motor).

Could you fit a pushrod V6? If so, a Ford 3.8L should be incredibly cheap to find (what's a 15-year old V6 Mustang going for these days?), crazy-cheap for parts, trannies can be found in every junkyard in the planet, and they actually can be built up decently if you crave more power. Ditto for the GM 2.9/3.8/4.3 V6s.

A KA24DE would probably be too tall, from the sound of it. Those aren't short motors.

I vote for a BP or a 13B.

ooooo! didnt think of a rotary... that might just be a great answer for this. but the KA24 sounds like it might work too. i dont think a v6 will fit without some modification. i have an early 90's ford 4.0 we are shoving in a fiat and it is seriously tight. plus having two banks of exhaust makes it harder to work though the steering/ brake booster stuff. for this application i am not sure i really want to get the added displacement/ gas usage anyway. i cant seem to find a miata for less than 2 grand around here that isnt a total basketcase. though i wont rule it out. relatively speaking do you know how much hp a stock rotary (i guess a 12) and a miata 1.8 make? would it be more or less than a KA24?

measure the actual width of the engine bay. an inline motor with intake and exhaust on opposite sides can end up being as wide as a narrow V6. I'd take the measurements and then go for a 60* GM V6 or a nissan VQ motor. I don't think you'd enjoy the KA motor, it lacks something IMO. if you want narrow and goofy you can always try to source a VE30DE. Not a common motor, but worth 190hp and fairly bulletproof other than the dang VTCs.

Why has no one said LS1 yet? If an LS1 fits in a Miata, it fits in whatever this is.

Any Mercedes is way too heavy for a low torque high reving engine. +1 on an LS1

2.3 16v Cosworth. I sold mine with the transmission for $1500. It might even bolt in with Benz mounts.

pilotbraden wrote: 2.3 16v Cosworth. I sold mine with the transmission for $1500. It might even bolt in with Benz mounts.

What cars would this combo come in?

itsarebuild wrote:

pilotbraden wrote: 2.3 16v Cosworth. I sold mine with the transmission for $1500. It might even bolt in with Benz mounts.

What cars would this combo come in?

E190 Cosworth.

In reply to itsarebuild:

I can try to get it back, the last I knew it was sitting in a self storage unit.

i'm still in the consideration phase right now. i dont even know what the owner wants for the shell or if he would part with it. but i will definitely keep that in mind! does it have all of the controls etc?

as for the LS1 recommendations, i agree an LS1 would make a very fun car. but that isnt what i am looking for with this idea. i'd like to get great gas milage, great reliability, low parts replacement cost, AND a very simple swap process. an ls would probably fit with the right kind of finess, but i am not interested in going through that kind of effort for the project when the goals dont require it. in this case i dont even think a t56 will fit in the transmission tunnel of the chassis i am looking at.

How much wider is a pushrod V6 than an OHC 4?

The pushrod motor would be shorter in both dimensions, too, with the less cylinders per bank, and the banks being leaned over.

itsarebuild wrote: as for the LS1 recommendations, i agree an LS1 would make a very fun car. but that isnt what i am looking for with this idea. i'd like to get great gas milage, great reliability, low parts replacement cost, AND a very simple swap process. an ls would probably fit with the right kind of finess, but i am not interested in going through that kind of effort for the project when the goals dont require it. in this case i dont even think a t56 will fit in the transmission tunnel of the chassis i am looking at.

Actually, the super-tall 6th gear typically improves fuel economy after an LS swap. Reliability should be top-notch too.

I have found some cheap 2.3 mercedes engines in scrapyards in the southeast. They are the 8v version but they are a good engine.

www.car-part.com

That car is going to be alot heavier than you think. Even the lightest W113 is going to tip the scales north of 2900lbs. If it is a R107, add 400-500lbs more.

Toyota 22RE + 5spd might be not bad. If they can push around a 4Runner should be able to do a Mercedes.

Tom Heath wrote:

itsarebuild wrote: as for the LS1 recommendations, i agree an LS1 would make a very fun car. but that isnt what i am looking for with this idea. i'd like to get great gas milage, great reliability, low parts replacement cost, AND a very simple swap process. an ls would probably fit with the right kind of finess, but i am not interested in going through that kind of effort for the project when the goals dont require it. in this case i dont even think a t56 will fit in the transmission tunnel of the chassis i am looking at.

Actually, the super-tall 6th gear typically improves fuel economy after an LS swap. Reliability should be top-notch too.

you are right, if i were to keep the rpms low and short shift the gas milage would likely be ok. however, if i drove the same way with a smaller displacement 4 banger it would be even better. dont get me wrong. if an ls motor showed up with a t56, a working ecu and harness, and a full a/c system on my doorstep i'd be deliriously happy and would find something to put it in ASAP. and if i were designing this project to be a track car i wouldnt have even needed to ask the "what engine" question. but i think finding an affordable ls package and the added expenses/ time to fit it in such a small compartment will put it over my budget for money and effort and that doesnt make sense to me when the goal is to make a dead nuts reliable, easy to assemble, and very efficient dd.

Maybe a little too modern- a 2.3 Duratec from a Ranger or B-series?

Or an older 2.5l?

Or the same engine from an S10?

At least the small PU engines are used to heavier loads.

that's if you can't source a Mercedes, I'd say. What pb has found seems like a killer solution.

m4ff3w wrote: That car is going to be alot heavier than you think. Even the lightest W113 is going to tip the scales north of 2900lbs. If it is a R107, add 400-500lbs more.

it doesnt have any badges on it and it is missing some trim, so i am not sure, but i think it is an SL 250. do you know how much they weighed? and how much of that weight was the old inline 6 motor?

ArthurDent wrote: Toyota 22RE + 5spd might be not bad. If they can push around a 4Runner should be able to do a Mercedes.

i thought about pickup and suv combos first as they are some of the few remaining rwd 4 cylinders, but the trucks i have driven seem to have pretty clunky shifter linkages. (the used s10, ranger, and tacoma trucks i have driven did anyway) it also seems like the intakes on the truck models are taller than the car equivelents. probably not all of them though....

are there any trucks out there that have smoother shifting transmissions that i should look into?

bmw m20, m30, or m50 variant. if the engine bay is wide enough for the slanted layout, theyre torquey, reliable, and can be efficient with the right gearing. plus theyre abundant and have good transmissions behind them stock.

edit- missed the 4cyl part. if you cant fit the i6, howabout a volvo 5-cylinder or b230 turbo 4cyl?

I guess when mercedes ended the c111 rotary project old man Wankel was none too happy. I read an article about how he took one of the prototype rotary engines and put it into a 450sl. I guess the rotary put out something like 350hp and would pull the car to 150mph. Old man Wankel called the regular V8 engine a "reciprocating bone shaker" as the rotary is much smoother.

We need to know exactly which model mercedes you are talking about. If it is a w113 it is worth keeping together.

itsarebuild wrote: are there any trucks out there that have smoother shifting transmissions that i should look into?

How about a manual? Would be a pain to add the third pedal, though.

Other than that, I thought the more recent ones were a lot better. But that make it a tougher install....