W114 engine swap ideas - PeachParts Mercedes-Benz Forum

Admiral Ahani · #1 10-16-2017, 03:49 AM

Hi guys, one of my friends has a very nice condition 1974 W114 280 automatic, and he wants to put a new engine in it. He loves the styling of the car but not the performance.

Nothing against the M110, but he wants more power and also something more modern. EDIT (incomplete sentence) He's not too interested trying to milk the M110 for more power with turbos, etc.

So we put the car in my garage and I took the engine out for him, and also did research on what other Mercedes engines would fit. Long story short, I learned that the W114 shares the front subframe with the R107 (which came with the M117 v8). I also found mention of a M117-swapped W114 on the forums (just a couple of pictures), and a red W115 with a 560SEL engine, so I convinced him that that was the way to go! We bought a 5.6L M117 and brought it to my garage.

Well we measured, measured, and measured some more. The W114 engine bay is freakin' narrow! We both really don't see how we could stuff a M117 in there. We know it's been done, and we saw the build thread of that red one, but it just looked too tight for comfort. We especially didn't like the header situation. The custom headers that that guy made were amazing, but my friend wants this to be a street car so he wants soft motor mounts, and he doesn't want the headers hitting the frame rails or steering box, etc. Also, the flow through those headers can't be very good. Never mind trying to work on the engine after it's stuffed in there. So we gave up on that engine. Now we're trying to think of a better one.

My friend has no idea, he just knows he wants at least 250hp. I figured I'd start a discussion here about it. What engine, whether it's Mercedes or not, do you think would suit a W114 well?

I've always wanted a vr6 in my 300td, so I told him we could put one in the W114... what do you guys think?

Since they're smaller than OHC v8s, we could try an american pushrod v8...

Any MB engines worth going for?

zohar.melamed · #2 10-16-2017, 05:32 AM

A Toyota JZ would fit and I have seen a thread with that conversion.

W114 280 1974 light ivory
W108 280SE 3.5 1972 pine green metallic
R107 500SL 1984 champagne metallic

Frank Reiner · #3 10-16-2017, 09:23 AM

AA:

Not only is the engine bay narrow, but so is the transmission tunnel.
If you depart from MB transmissions there is a considerable likelihood of doing floor modification.
The narrowest of US V8s is the pushrod Ford 289/302 series. The AOD transmission that mates with those engines does not require any electronics, but will need a bit of floor bashing to provide clearance at the right front corner of the tunnel.

60 degree V6s are also narrow, but a bit tall.

Tomas7 · #4 10-16-2017, 10:42 AM

Wouldn't it be easier to extract some more HP (250+) from the 110 motor?
Hasn't this been done before by someone here?

Scrappy · #5 10-16-2017, 02:07 PM

I have an M104 in a 1995 W124 (E320)

I've been thinking about using it and its accompanying transmission as donor material for a 250C

it's been done

https://www.youtube.com/watch?v=RW1IoJ6NIqo

Admiral Ahani · #6 10-17-2017, 06:14 PM

Sorry, I left an incomplete sentence in the first post - we don't think we can get the power he wants out of a M110 without converting it to turbo, and at that level of work he'd rather have an engine that already produces that power, and is an overall better engine to boot.

What are some good 60-degree v6s? Are there any 60-degree v8s worth using?

As far as the transmission, we could keep the MB trans and adapt it to the new engine... or at least we can see how hard it would be. Or maybe the new engine could be mated to a small enough M/T.

Frank Reiner · #7 10-17-2017, 06:39 PM

Quote:

Originally Posted by Admiral Ahani

Sorry, I left an incomplete sentence in the first post - we don't think we can get the power he wants out of a M110 without converting it to turbo, and at that level of work he'd rather have an engine that already produces that power, and is an overall better engine to boot.

What are some good 60-degree v6s? Are there any 60-degree v8s worth using?

As far as the transmission, we could keep the MB trans and adapt it to the new engine... or at least we can see how hard it would be. Or maybe the new engine could be mated to a small enough M/T.

1) There are no 60-deg V8s; V6s at 60-deg are in good primary balance (as are V-12s), and that is the reason for that configuration. A 60-deg V8 would have very poor balance, as does a 90-deg V6.
2) Many of the Asian V6s are 60-deg; when used in light trucks they are configured for rear wheel drive and have good transmissions, both auto and manual. The push-rod Mopar 60-deg V6s of the 90s (LH? chassis) are good candidates; even though they were front wheel drive the engines were longitudinal.
3) Most M/Ts that are appropriate for the anticipated power will fit in the tunnel OK.

Tomguy · #8 10-17-2017, 09:26 PM

The 3.5 in a Chrysler LH is an OHC, but yes it's longitudinal - and not a bad looking engine. It's 250HP stock though, so if you want more, you're probably looking at a BUILT 302 (the 302 in stock form is lower HP than the Mopar 3.5 V6). The GM V6 were pushrods but I believe they were 90 degrees with a balance shaft, and they were terrible for power. The 3.8 supercharged was only slightly better than a stock Mopar 3.5.

Frank Reiner · #9 10-17-2017, 10:46 PM

Tom:

The 3.3 & 3.8 pushrod 60-deg Mopars date from 1990/91, were used in 1st gen LHs, and finished their run in 2010 in Jeep Wranglers. Iron block, aluminum heads.

Admiral Ahani · #10 10-18-2017, 02:51 AM

I got to thinking about 60 degree v8s and I found this
https://en.wikipedia.org/wiki/Ford_SHO_V8_engine
I wonder if it would fit in the W114. But it looks to be a bit low on power.

Tomguy · #11 10-18-2017, 08:36 AM

Like a 90 degree V6, a 60 degree V8 does not have a natural balance. A 60 degree V6 has natural balance because every cylinder fire occurs at the same spacing (in crank rotational degrees) from the last one. Same with a 90 degree V8. Engines that are not naturally balanced have a power-robbing balance shaft. If you know that and don't care, it's not a big deal, but it's something to be aware of.

Frank: I forgot about first-gen Intrepids (and others) with the 3.3. According to Allpar, that 3.3 and 3.8 started in 1990, not related to an earlier design. I also forgot that Chrysler made a 4.0 version of the 3.5 V6, and put it in the Nitro, longitudinally, attached to a Benz 5 speed (NAG1) trans. Not much more HP than a 3.5, but more usable torque, and already attached to a RWD transmission.

I can measure how wide my Hemi in my Jeep is if you're feeling really daring! Haha.

Idle · #12 10-18-2017, 05:14 PM

Not that I am considering such a swap myself, but.....

How much HP can the rear end on a 114 take?

Has anyone ever tried to use a 116 rear end in a 114?

I'm asking for a friend.

Tomas7 · #13 10-18-2017, 08:21 PM

Quote:

Originally Posted by Admiral Ahani

I got to thinking about 60 degree v8s and I found this
https://en.wikipedia.org/wiki/Ford_SHO_V8_engine
I wonder if it would fit in the W114. But it looks to be a bit low on power.

The SHO V8 is a wide motor on top. There was also a 3.0 V6 (220 HP) Yamaha engine that the previous SHO cars had. It was way more dependable and smaller. Both of these motors were placed in their cars longitudinally.

http://carphotos.cardomain.com/ride_images/1/3393/2741/8481370044_large.jpg

rbtoj · #14 10-20-2017, 04:41 PM

Most people who "want x amount of power" are actually talking about torque, and don't know it. I think you need to ask your friend what is he expecting form this 250hp engine.
Also, a late euro spec M110 has quite a bit of poke (185hp), an can be easily converted to run modern ignition and electronic fuel injection. Such mods could allow you to play with ignition timing a bit, and achieve low 200hp, and a very very rev happy engine.
It would cost much less, and be a lot less trouble.

EDIT: Also, the cam timing on this late m110 is very mild, because of a limitation of the original k-jetronic injection. With a modern electronic injection you can dial in a little bit of valve overlap an get even more power.

Admiral Ahani · #15 10-23-2017, 05:57 AM

I know about engine balance, but it doesn't really have any bearing on our decision making process. Balance shafts don't rob that much power. Now, personally, I do care a lot about these details because I don't like cranks with split pins, uneven firing, etc, but my friend with the W114 doesn't care that much.

Yes, he wants torque, as well as power. He wants everything!

A Jeep Hemi, eh? Fat guy in a little coat....

I've heard that the Ford SHO v8 is more reliable than the yamaha SHO v6. And both were mounted transverse. The v6 could be mated to a ford longitudinal transmission, I don't know about the v8. The yamaha produces very low power/torque for its redline and its displacement, I considered it for a swap in another car once.

Where can I buy an M110 EFI kit? And where can I buy a cam / who knows how to reprofile an M110 cam?