Shim Shim

[Skippermitch]

Hello All   So I hear of adding and removing shims, under the WRD, BC, and even on my 380sl transmission modulator.  What material do I use?  Steel, aluminium, brass, stainless and next up.... the best way of making one.  I hear oval under the WRD.  I am running slightly rich and would like to start by shimming under the WRD.  Thanks in Advance

Mitch  1964 230SL  Ivory/Havana Brown

[wwheeler]

You do not want to start messing with shims until you know what each shim does. They all have a different effect on the engine. And by all means, keep track of the shims you add so you know where you have been. The WRD only effects the fuel mixture when the engine is cold. NOTE: there are two types for the WRD (round and oval). The BC effects the engine at all ranges hot and cold.

So you need to determine where you are running rich; hot/cold, high RPM/idle etc. I would also strongly recommend you go through the linkage tour. Most engines with mixture issues have linkages that are not set properly. http://www.sl113.org/wiki/Restricted/Linkage-tour

As far as the material, I do not think that matters as much as the thickness. You will need several thicknesses - .003 - .020" would be a good start. You can buy punch sets pretty cheap on the internet and that is what I use.

I hope this helps.

[Skippermitch]

Hello Wallace,
 I tested the WRD and it moved the 2mm properly. Also before I freed up the Check Valves in the IP it operated seemingly well.  The engine would run and then not when it got hot. I freed up the check valves and got the engine running pretty good although it seems a little rich. I went carefully throught the linkage tour and it was off a little bit.  All the cold start items have been tested and work good....the car starts right up. I can tell I am running rich with a split linkage test. I have also tightened the idle air screw almost to the stop.  If I open it and give it more air the engine idles too high. I attempted to unscrew the BC but it is quite stubborn right now. I am soaking it with solvent. When I do get it loose I will mark it and use it manually to see if I can get a more lean condition.  Next will probably be a wide band O2 meter, seems that is the best way to go.  Right now just trying to get the engine in the neighborhood.  I am also waiting on a 14mm valve tool, 6 weeks or so. Thanks for the response
Mitch

[Skippermitch]

Here's an update....WRD piston was siezed up. Removed the unit from the IP and got it moving again.  Still running slighlty rich....BC shim,shim is next

Mitch

[ctaylor738]

I can only echo what Wallace says - don't mess with the pump unless you know what you are trying to fix and have the means to test the change.  There is really no way to tell if you are running "slightly rich" except with a wide band sensor or a gas analyzer while the car is being driven.

If you have your heart set on a seat of the pants adjustment, though, go one click lean on the rack.  That's what the adjustment is for - to change the mixture across the board.

[Skippermitch]

Thanks for the advice....removed .010 from the BC....everything working much better although had to readjust the idle mixture and idle air.  a split linkage test showed still slightly rich at idle. The WRD is kicking out at 130 F which is a little early. all and all seems to be much better during a road test... next up will be a wide band O2 set-up. Still looking for a 14mm valve tool and seems my brake booster is the wrong one.

Mitch