1972 Mercedes 4.5 liter Horse Power?

[JeffreyNMemphis]

Hello Friends,

I was looking for information about the horsepower of the W108 chassis 280SEL with 4.5L V8 engine M117.

According to Wikipedia.com, the 1972 Mercedes 4.5 liter V8 engine was 222hp ROW and 195HP USA model (Torque 278ft-lbs. ROW and 240ft-lbs. USA). I don't look for motor information at Wikipedia, but a search popped that site up so I read it.
Is this correct? Why is there a difference between ROW (Rest Of the World) and USA models?


I imagine it would have something to do with pollution control. The 1973 280SE 4.5 that I owned twenty years ago would smoke the tires off the line. My current car is the longer bodied SEL model, which feels more civilised and not capable of tire squeeling misbehavior when I launch it from a red light. I wonder if my old car was running without pollution reducing/controlling kit, and my current car is the way it left the dealership.
Thank you in advance for sharing your knowledge.
Jeffrey

[Wodnek]

It is indeed the polution controls of the era. These robbed power by reducing compression, retarding timing, intalling cats, and all sorts of other goodies.
Engines had to get bigger to keep the same power. Cars got weaker and weaker through the 70s and early 80s until fuel injection technologies caught up. Now through technolgy we can have a horse per cubic inch once again and have clean exhaust.

[PanzerSD]

So then, eliminating an air pump, EGR and cats and nearly anything else attributed to emission control, Jeffrey and I can have 200+HP?

[PanzerSD]

And What is a "Gravely"? it's in your sig.

[deanyel]

It has 230 HP under the old SAE standard and 200 HP under the present DIN standard. 1972 was considered a good pre-emissions year. It was the 1974 standard that really made them anemic.

[Tomguy]

The cam and head on US models starting around 72 or 73 had lower compression and relaxed timing for better emissions. This can be "Circumvented" by swapping heads from the later engine.

No 108 or 109 to my knowledge ever came with catalytic converters.

[diametricalbenz]

Which year heads would be ideal for exchanging onto the 1972 and later model cars?

[JeffreyNMemphis]

Hey Guys,

Thanks for the replies.

My engine is the M117.068. The Mercedes Manufacture plate on the door sill says it was made in 8/72 (August 1972). Is that a good emissions year car? What are the components that are robbing it of performance? It was special ordered for delivery to a doctor in Illinois, so it would not have California only emissions kit is something like that exists.

Tomguy: Which year heads (from which motors) are candidates? Would that raise my compression? I would be more likely to remove a pollution device than change the heads, but neither option is something I think would be desirable or add lasting value. If the car was a beater that I was just fooling around with it could be an option. But my car is one of the low mileage examples that has been maintained and enjoyed a garage queen life before I acquired it.

I considered buying another one to do modifications on. If I was saving a car from the scrap yard I would not consider swapping heads or adding a super-charging system a criminal offense.

[GGR]

Would heads out of a 3.5, including cams, bolt on the 4.5, and would that make a difference?

[Tomguy]

3.5 heads/cams are the best bet. They fit and yes, they do make a difference. You NEED to run premium if you do it. Make sure your bottom end is 100%. I do not know how long the engine lasts like this - I can tell you once I get mine back on the road . It makes a noticeable ass dyno difference.

Got the 3.5 heads, think I'm good to go!
My headjob is in progress!

[JeffreyNMemphis]

Tom,

When are you going to get Quick Silver back on the road? I have been reading about it for two years! Did you finish rebuilding the motor? What was the final decision you made about cams? Did you dyno the engine on a stand?

You might find a nice W108 with a blown motor... since Quick Silver is turning into fools gold (rust).

[Tomguy]

As of right now nothing, as I am in an apartment away from the car - I need to wait until I get a house with a garage to begin resuscitation (or an engine swap into a dead 108). I never had the engine dynoed. It's still got the 3.5 cams in it, I decided to leave it alone until I can use a dyno on it!

[berfinroy]

Don't the pistons also contribute to the higher compression on the 3.5 engine?

[Tomguy]

The pistons on the 3.5 are slightly dished, the 4.5 pistons are flat-topped. I am unsure if the 3.5 pistons are taller or not - in the 4.5 the piston does not go all the way to the top of the bore. However, doing pistons AND 3.5 heads in a 4.5 would be far too much compression. It's already above 12:1 according to revised calculations with the heads.

[PanzerSD]

a 3.5 engine has 12:1 compression!?! my 4.5 is probably only around 8 or MAYBE 8.5:1