I am cleaning the trigger points, What is this? - PeachParts Mercedes-Benz Forum

JBR · #1 03-18-2006, 10:24 AM

I have the trigger points out, I wanted to clean with white paper. I see now that they are encased in a clear plastic surround guard. Is this removed or do I remove the c-clip and take 1 set of points out at a time to clean?

stevebfl · #2 03-18-2006, 12:41 PM

Yes.

dkveuro · #3 03-18-2006, 01:34 PM

As old as they are they do get very brittle...the cover that is.

Remove cover as carefully as you can....if it cracks/splits....it is no real problem, it is a dust shield.

ps...I presume you are refering to the trigger points in the distributor that fire the injectors ? Seems Steve knows what you mean

.

JBR · #4 03-18-2006, 05:33 PM

Well I cleaned via brake kleen and compressed Co2. The plastic guard baffled me. I could not see how it could be removed. I reinstalled and started. Tryed to set timing but no way can I get to 5* atdc. The dist. is maxed on the slot, I wonder if someone had removed and put it in 1 tooth off. BTY it is set the same as it was before I removed the dist. Runs better but still has a horrible miss. The closest I can get to the correct timing is 10* btdc. Now this is with vac line connected to dist. Also this is looking down betweem the radiator and engine, if the mark is on the left side of the pointer then that is ATDC if the mark is on the right side then its BTDC. Is that correct. The dist. slot will not even allow me to get to TDC (0). Any ideas? Thanks
I set the dwell to 30* before I did anything

stevebfl · #5 03-18-2006, 05:51 PM

What is the timing with the vacuum line off? If it is the same then you are fine if you are reading it correctly. Hell I don't know right or left, but the engine turn clockwise as viewed from the front. The TDC position is coming over the top and heading to the pointer. If the firing takes place before TDC gets to the pointer it is BTDC. If the balancer TDC passes the pointer before firing it is after tdc ATDC.

If you look at the balancer marks there are marks to 50 or more degrees on the BTDC side and only to 20 on the ATDC side. Look at it with the motor stopped and put a mark with white shoe polish or something, where you understand it so it will be more visable in movement.

Once you are close, listen to the injectors with a stethescope or a long thin screw driver. Place the screw driver tip on each injector and place the handle to your ear. The injector are easy to hear. If you have a pair of injectors not firing in firing order you have a trigger point issue most likely.

When that system was new MB suggested replacing trigger points every 30k miles. As the cars lost value and the points gained, the concept of replacement for maintenance was lost. The original points didn't have the plastic covers. The covers can be removed and replaced. It is real difficult and might require unsoldering each point, I forget. Once you are sure there is a problem break the plastic out of the way. The wear blocks wear out though and the points just won't open far enough. Especially if there is shaft bearing wear. If there is shaft bearing wear the ignition points will push the shaft to one side and the trigger points below will open large on one side and not of the other. As the wear blocks wear one side quits openning.

JBR · #6 03-19-2006, 07:46 AM

Is it possible that the dist. was reinstalled 1 tooth off? The vac retard does work, if I suck on the diaphram valve(on the dist) it does move the internals of the dist. The vac line going to the dist. also has vac. it will stick to my lip. But when the car is running and you remove the line it does not change the idle. That is why I am wondering that the dist. is 1 thooth off. The best it can be timed at is 10* btdc. no more movement left in the slot to turn the dist. I will try to reinstall the dist. off one tooth from where it is now. Hoping to give me more adjustment, Cheers.

Tomguy · #7 03-19-2006, 11:59 AM

JBR: You're probably best off in the Vintage Forum for stuff like this, just so you know

You definetly installed your distributor 1 tooth off. (It may be easier to turn your engine to TDCto do this). Make sure your rotor is as far counterclockwise as it will go. Mark on the distributor where it is. Your timing is too advanced? Remove the distributor (the rotor rotates when you pull it out - don't touch it yet). See where the rotor is? Turn it counterclockwise a bit, then put your distributor back in. With the distributor in the exact same position as before, your rotor should be further counterclockwise (think 12:00 as opposed to 1:00). Turn your distributor so your rotor lines up with your mark and put the retaining screw back in. Now check and set your timing, make sure it's 5° ATDC WITH the vac line connected.

JBR · #8 03-20-2006, 07:27 AM

Tomguy Thanks: you are correct, that when I remove the dist. the rotor does turn slightly as it follows the gears out. I beleive what you are telling me is while Im reinstalling the dist. to rotate the rotor slightly so it slides into 1 tooth over. One other observation I made was.
I tried to put the TDC mark on the pointer, I got within maybe 2*. Then removed the dist. cap to see if the rotor was pointing at the #1 plug wire position on the cap. Well it was not it was opposite say 180*. I imagine then that the #1 cyl was not on its compression stroke. What size wrench goes on the nut on the bottom pulley? There is no way I can see the nut the pulley is so deep. I'll just keep dicking with it. thanks