Custom ATI Super Damper for the M113

If you’ve been reading this blog for a while you know that my ultimate goal is to run a high 8-second quarter mile in the CLK. In order to do that without getting kicked out of an NHRA-sanctioned track, I plan on building the car to the rulebook and having it be 100 percent legal.

According to the NHRA Quick Reference guide, one of the things you need when you go 10.99 or quicker is an SFI 18.1 certified harmonic balancer. Not surprisingly, nobody makes one for the M113 found in the W208 CLK55. Luckily, ATI will make custom versions of their Super Damper, which is SFI 18.1 certified. I was told to expect up to a 2-year wait for a custom damper, so even though the car is currently stock, I placed the order for the damper expecting it to be ready in a couple years when the car should be running sub-11 second ETs.

Reference Drawing Number SK260G1 for a 6.2 AMG (18% overdrive) if you want to order one from ATI.

Ahmad from East Coast Euro was kind enough to send me his old stock balancer so I could send it to ATI for them to use as a guide for making mine. As luck would have it, they already had the engineering for a 6.2 AMG, which apparently has most of the same dimensions as the M113 pulley. This saved me time and money, since all they had to do was build one they had already engineered. The one difference is the Super Damper is a larger diameter, making it an 18% overdrive pulley. The clearance to the water pump pulley was going to be very tight, so I ordered a smaller one from Weistec.

Removing the Stock Pulley

I went ahead and removed the radiator and the AC condenser (since my refrigerant is long-gone!) to make the bolt much more accessible. You might be able to do this job without removing the radiator, but you will risk bending the fins. It’s worth the few extra minutes it takes to get everything out of the way. If your AC system is charged and working properly, then you should probably leave the condenser in-place and just remove the radiator.

I purchased the special crank-holding tool for removing the stock pulley, but in hindsight I should have just used an impact wrench. This will be a one-time use tool for me, since it won’t work on the ATI damper (or my E55’s pulley).

I used a piece of steel pipe slipped over the crank-removal tool to hold the pulley still while I loosened the bolt.
I used two pieces of iron pipe for loosening the bolt; one to extend the 3/4″ breaker bar for more leverage, and another to extend the crank-holding tool to the frame.

After removing the bolt, the pulley will just walk off the end of the crank with a little wiggling. Don’t forget to install a new front main seal while you’re in here! Mine had over 220k miles on it and was very brittle. I made a simple installation tool by using a piece of pipe nipple and a bolt with a stack of washers. It was very easy to tighten the bolt and pull the seal into place evenly.

The front seal is easy to install with a pipe nipple, a bolt, and a stack of washers from the local hardware store.

Installation

I reached out to my buddy Josh from Creative Steel to make me a special tool for installing the Super Damper hub. He whipped up a beefy piece that bolts to the hub and extends out to the frame rail, which held the crankshaft while I torqued a new factory Mercedes bolt to the required 148 ft-lb plus 90 degrees. This job would have been nearly impossible without that tool, but it only took me 2 minutes with it — Thanks Josh!

Once the hub is torqued, it’s a simple matter of putting the damper assembly on, in the right orientation, and torquing the nine bolts that hold it to the hub. I followed the instructions that came with the damper for that step. With the smaller Weistec water pump pulley there is plenty of clearance, and the factory belt barely fits.

There is plenty of clearance with the smaller Weistech water pump pulley. Notice the timing mark at 12 o’clock on the front cover of the engine.

Now I’ve got an SFI certified, rebuildable damper on the car so I don’t have to worry about the factory piece coming apart when I start spinning this motor above 6500 rpm, and I’ll be ready for those 10 second passes if they ever come!

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