190SL Ignition Coil, Wires

[bstreep]

As many might know, I have a Crane electronic ignition in my car. Just trying to sort out a miss I have when the car is cold, and I want to eliminate as much of the electrical system as possible. I measured the resistance of the plug wires, and they are 5K. The coil to dist. cap is 9K (???). These sound OK?

The coil looks like an original. Is there any way to check it to make sure it's behaving correctly? Would I be better off to buy a newer or aftermarket coil? A replacement from Star is only $30... BTW, Cranecams website is down.

Thanks in advance as always,

[hgupta]

I'm no expert (but you already know that, Bill!) but I would guess that it is not your wires since wires build up more resistance as they get hotter. I know that many older coils are affected by vibration, and if your car is like mine, it shakes like an old man when first starting up. I went with a high end aftermarket coil from MSD(the blaster 2). It was also $30, but it produces a really nice spark and fits into the original bracket.

[bstreep]

Hemant, where did you get your coil? Thanks,

[hgupta]

I got mine from a local speed shop. Its also available from http://www.carparts.com Just search for "blaster." I went with the blaster2 model 8202. Any performance store in town will carry the MSD ignition stuff. This coil has worked great in my car. I believe it is also available in black, according to http://www.msdignition.com but I haven't seen it. The owners of the speed shop prefered the MSD to crane coils by far.

[Jim Villers]

Bill ... The original wires were copper with no resistance. There is a resistor internal to the original rotor (Robby soldered a wire across his for a "hotter" spark). As I recall from a picture of your engine compartment, your have Bosch plug ends so the wires should just unscrew from them. Try going to a speed shop and buying solid core plug wire. Better yet, Star Quality sells the wire for $25 and the plug ends for $9 each. (If you are very frugal, you can reuse your late model Bosch plug ends.)

With that said, I doubt that plug wires are the cause of your cold engine performance (even though southern Texas is never cold compared to the rest of us). The electrical system performance should not change because of changes in temperature. Fuel delivery, however, is very important and a cold engine requires a richer mixture than a warm engine. When cold, my engine needs the choke for the first few minutes until the head warms up. I consider using the choke as normal. I also think that if the mixture is rich enough that you don't need the choke when it is cold, that it would run too rich when it is warm. What we need is an exhaust analyzer to figure out what is really happening.

[bstreep]

Jim, I've got an order to get together for Star, so I'll add that to it. I know Robby had mentioned that the 5K wires were better? As for the choke, Will Samples says that it really shouldn't be necessary for Webers, although before I fixed the intake leaks I had to use them... As for ignition, I just wonder if I'm getting a marginal spark that's not as critical when hot as it is when the engine is cold.

[Arthur Dalton]

If you are talking 9k ohms on the primay wire,
change it to a solid core and see how it runs.
As Jim V. said, the wires are supposed to be solid
core, [ hardly any resistance].
The resistance in the circuit is from the plug end resistors at the plug and the rotor/carbon at the cap.
This is a better system in the sense that all plugs get the same resistance , regardless of wire length.
Solid core wire can be had at any good auto store and
making up a new set is short $$ and an easy screw on swap.

[Jim Villers]

Bill ... It is just magic. You keep "fixing" things until it works and you credit what you fixed as the problem.

My current problem is syncing my carbs. I can sync them for low throttle or high throttle but not both. I think it has to do with the location of the idler shaft and the angles of my linkage rods. Ever since I "fixed" my idler shaft bearings and installed new linkage rods, it has not been right. With all of my tinkering, I now realize that it had never worked correctly and the vibrations I thought was "normal" was in fact a carb sync symptom. Robby is going to send me the measurements from his and I will begin experimenting next week.

[bstreep]

OK, so does that mean that they have different "throws"? I guess I need to look at my rods and see if the two match in length. Even with new ends on the rods there's still too much "slop" in them, in my opinion. Someone needs to build a good linkage for these beasts. It's UGLY how we have bastardized 45 year old engineering - we took what was just ok back then, and then modified it (poorly, at that) and expect it to work right.

I'm also not convinced that I don't have a couple of carb problems. I've leaned out the idle circuit and the main circuit, but I'm still running rich. I have a fuel pressure regulator on the fuel line. I've adjusted per spec the float levels. I've tightened and retightened intake nuts, made step washers for them, put anti-vibration gaskets on them, you name it. Who knows how many times I've tuned them. The car runs better than ever now, as long as 1) the plugs are clean (and the hotter plugs have helped a bunch) and 2) the car is warm AND it's been through one hard acceleration.

[hgupta]

No kidding, my linkage is really sloppy! I noticed the same thing about the carbs not being synced at both low and high throttle. The angles are all off, one carb is back carb than the other. If I were to design a linkage it would be mounted on both carbs, not just the front carb with a dinky pushrod for the rear.
Where is this resistor in the rotor that Robby jumpered over?
Bill, I forgot that I also had a similar problem with missing when starting. When my mechanic came over to help resolve my timing issues, he noticed a lot of crud under the plate that the points bolt onto. when he turned the rotor shaft by hand, you could see that the centrifugal advance arms were not moving smoothly (that's what he called them). So he pulled them off and cleaned them up and put them back. If I recall, you set your timing at 3000 RPM, but at really slow RPM these centrifugal advance arms may not be where they should, throwing off your timing. Hows your timing at lower RPM, does it follow the graph?
I got the timing pointer for my car, but I am having trouble visualizing where it should bolt onto. Is supposed to be attached by the same bolts as the motor mounts?

[bstreep]

Hemant,
Distributor was cleaned up last summer with a rebuild. I actually had a broken spring on the advance! I don't know where the resistor is/goes, nor do I know how the pointer should work. Jim might... We really need a good solution for these carbs...

[hgupta]

Have you seen EricH's linkage that he machined? I have only seen the pictures (http://www.peachparts.com/shopforum/showthread.php?threadid=11331) but what he has seems ideal: the throttle pushrods are parallel and look like they both push straight down. I think our mistake is trying to combine new and original parts in the linkage. I think I will try to design a new one this weekend.

[Robby Ackerman]

Hemant

Any number of things may be impacting your cold running problems. To start with you cannot adjust the carbs if you have ANY slop in the linkage. So that must be fixed before looking at other things as a possible problem area. New balls and sockets are available and are not expensive. The car can run perfectly with this original setup. Jim and I replaced the balls & sockets with aircraft cable ends that use roller bearings and there is zero play. It is not an easy conversion but worth doing at some point. Getting back to the cold running problem, I can always tell when my valves are out of adjustment by .001" or .002" because it will run rough when cold.

Yes timing is set at 3000 rpm. Don't pay any attention to what it is at idle. Also, once the slop is out of the carb linkage the carb linkages should be adjusted at full throttle not at full stop (idle). You don't drive a Benz at idle, right?

Robby

[Jim Villers]

Hemant ... The rotor resistor is between the center button and the end contact. If you didn't know it is there, you would never suspect it. Just check it with an ohmmeter.

Got nothing done this last weekend .... spent it with grandkids.

All of the talk has made engine run rough cold at low RPM's and has also seemed to exaggerate my "flat" spot in the 1900-2300 RPM range. Somehow, my "simple" project has become harder. My only consolidation is that it runs great on fast cruising and high power (it just seems to just like it there). Why is tuning an engine so hard? I used to be satisfied with the way it ran. I am just about ready to start over with my linkages from scratch. I have the feeling that the main beneficiary of this thread will be the Weber parts distributor.

[bstreep]

I'm going to get into this tonight. Spent the weekend at the coast (the BEACH if you're not from Texas, or "THE SHORE" if you are from NJ/PA). Had a great time racing sailboats (my other passion) and partaking a bit too much of adult beverages... As you can guess, I'm not that happy about how mine is running. BUT, 3 years ago I'd have been ECSTATIC about how it runs now. Oh well... the search for perfection.