98 SLK 230 Question

The car has about 76,600 miles, and had it since it had 40,000. Is it time to change the Spark Plugs?

How often do you guys change your Spark Plugs?
How many are in the little 4 cylinder?

Will it add any (at all) hp to it with new Spark Plugs?

Thanks!

 

are you sure you want to do it yourself? you asked how many spark plugs are in a four cylinder???? Mine has 80,000 and I changed them as soon as I bought the car. it ran better and smoother. so go for it!

 

various quotes fro a 10 second google search:


Normal engines have one spark plug per cylinder. However, since decades ago, Alfa Romeo insisted to put 2 spark plugs in each cylinder. As ignition takes place in two locations rather than one, this enable more efficient combustion and cleaner emission. However, besides Alfa, in the past 15 years only Mercedes and Porsche have ever applied Twin Spark design to their engines. This is mainly because of the complexity of cylinder head - it would be too difficult to put 4 valves and 2 plugs into the small cylinder head area. ( Mercedes' and Porsche's engines are 3 valves and 2 valves per cylinder respectively, so they have no such problem.) Only Alfa Romeo applied it to 4-valve engines.




1906 Six-cylinder racing engine with machined steel cylinders and overhead camshaft with vertical shaft drive: provides inspiration for aeroengines and high-performance car engines
First Mercedes produced in America is delivered.
two spark plugs per cylinder engines




1910 Benz Prinz Heinrich Wagen with 4 valves and 2 spark plugs per cylinder




1911 Mercedes 37/90 PS with three valves per cylinder and twin-spark ignition




1997 New V6 and V8 engines with three valves per cylinder and twin-spark ignition
Sidebags for driver and front fitted as standard throught the Mercedes-Benz passenger car range



The heart of any AMG automobile is the engine-each one a handcrafted thing of beauty. One individual spends about 2 1/2 hours assembling an AMG powerplant-then signs his creation. Racks of components await installation, virtually all of them being cast, forged, machined, or stamped out of one high-tech aluminum alloy or another. Engine blocks are exclusive to AMG, and feature cast-in silicon-aluminum cylinder sleeves and low-friction surfaces. These allow the piston-ring spring tension to be reduced by 50 percent, decreasing friction and improving fuel economy and power. The block is cast around the sleeves, melting about 20 percent of the outside of the sleeves, resulting in a very stiff block.

A new E55 AMG is inspected under special lights in order to detect any fit-and-finish flaws. Any discrepancies found are fixed before the vehicle is signed off and sent to its next station.

The twin-plug/three valve heads breathe well and also provide plenty of heat early in the start-up sequence for rapid heat-up of the catalytic converters. The DOHC design opens two intake valves and one exhaust valve per cylinder; twin-plugs fire at slightly different times, depending on the engine load and speed.

 

If you look in your repair book that come with the car. It say to change the plugs every 30,000 miles or 4 years. My slk has 95,000 miles on it and yeah it make a big different every time. I have done about three times now.