A few questions for the ignition experts out there

[B-Doon]

Today I decided I wanted to make my 02 run a little better, and in the process, did the exact opposite. I removed my spark plugs to check them, and the threads on the #1 cylinder were so gummed up it took significant force to remove the spark plug. So, I decided to chase the threads and replace the WR7DC plugs (I pulled a lot of crud and metal shavings out from all 4 spark plug holes).

The store did not have the W8DC's recommended here, so I went with the NGK's others have mentioned. I noticed that the WR7DC's were gapped to .03+ so I gapped the new plugs at .027. Before I started her up I also adjusted the valves while cold. It ran like crap, and I could barely keep it from stalling at idle... (For reference, I have a newish blue coil, and the Bavauto High Perf wires.)

I ran out of time for today, but my plan for tomorrow was to reset the ignition timing, and re-dial in the 32/36.

Two Questions.

1) Could there be any compatibility issues with the plug wires? I now see Bavauto's website saying I could use the plugs with the WR7DC's.

2) Is there anything else I'm overlooking? I wanted to check before I started playing with the timing and the carb.

Thanks-in-advance!

Brian

[JohnS]

the NGK plug that closely matches the heat range of the old Bosch W8DC is the NGK BP6ES. If you want the next hotter NGK plug, that would be the BP5ES. The lower numbered NGK plugs have a higher heat range. It's the opposite with Bosch plugs. WR7DC is cooler than WR8DC. The 'R' in the WRxDC means it has a built in resistor. W8DC didn't have a built in resistor. The BP6ES also doesn't have a built in resistor.

[B-Doon]

I bought the NGK BP6ES plugs

[Swiftus]

IDK which way your plug wires prefer, but did you make sure that you kept the same end on the spark plug. As in, you can either have that little screw-on doohickey or just exposed threads on the end of the spark plug itself. I know that I have been in a haste before and mixed up which way it was supposed to be. If that is the case, the plug wire will never seat properly and can cause chaotic ignition issues.

[Scott Sislane]

when you installed the new bosch blue coil you added resistance to your ignition, which in-turn weakens your spark, so you should remove the inline resistor (or resistor wire on 76's) to compensate for the added resistance in that coil. (better yet, put the stock coil back on)

Your stock wires had built-in resistance in the ceramic end, where the bav auto wires do not, so that should help, not hinder. Also, always possible one of the Bav Auto wires are faulty, causing a poor firing cylinder. (very possible)

Do you have points or a pertronix type unit? (in your distributor)

You sure you adjusted the valves properly? Have you done it before, w/ success?

Scott

disclaimer: I'm just an untrained snowbank wrencher.

[B-Doon]

I've got a petronix, and the valves have been successfully adjusted before. Only three of the eight really needed adjustment. Prior to my meddling, there was a small amount of valve chatter, which is one of the reasons I opted to play around with it today. No more chatter, just a rough running engine at idle. Under load at 2k RPM's it has never run smoother now... Except when at idle (900-1K) is it rough, and there is a small amount of smoke coming from the valve cover exhaust 'sock'

[Scott Sislane]

.....so the loose plug probably is causing the rough idle?

http://www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/t,365361/

[pip]

I also just added the "blue" coil and am now getting a weaker spark ( even though it ran great for a week) is there a write up and how to remove the resistor??

many thanks

when you installed the new bosch blue coil you added resistance to your ignition, which in-turn weakens your spark, so you should remove the inline resistor (or resistor wire on 76's) to compensate for the added resistance in that coil. (better yet, put the stock coil back on)

Your stock wires had built-in resistance in the ceramic end, where the bav auto wires do not, so that should help, not hinder. Also, always possible one of the Bav Auto wires are faulty, causing a poor firing cylinder. (very possible)

Do you have points or a pertronix type unit? (in your distributor)

You sure you adjusted the valves properly? Have you done it before, w/ success?

Scott

disclaimer: I'm just an untrained snowbank wrencher.

[Scott Sislane]

You just by-pass the white sandstone resistor. It's a fairly large white block, and usually close to the firewall on the pass side. The + wire feeds into it, and out of it. Just remove the 2 wires connected to it, and connect them to each other. But... you're still better off w/ the stock set-up, as far as I can figure. It's designed to give you hot spark at start-up, and proper spark when your key is returned from the start/fhart to the run position.