a case where i should have just left it alone

[Mike Hughes]

i was running the bosch w7dc but substituted new 7333 ngk's since the bosh were fouled.

If your plugs continue to foul try going to NGK 7832 (BP5ES, one range hotter).  Makes all the difference in my 230SL.

[Benz Dr.]

My 250 SL spec is 30 degrees advance at 3K rpm, doesn't specify vacuum or not, but there is no vacuum at 3K rpm.  It calls for 8 degrees at idle w/no vacuum.

The car starts, turns off and runs beautifully.

It's noteworthy to understand what those charts are telling you. All of those figures are for testing purposes only and are not for setting actual timing while runnng. The 051 distributor has 20 degrees of mechanical advance and 10 degrees of vacuum. Together they will give you 30 degrees of distributor advance and when you add the 8 degrees of idle timing you get 38 degrees total. Start your engine, then adjust to 8 degrees BTDC and increase RPM to 3,000 which should produce 38 total.

[Benz Dr.]

hi Dan
yup, i increased the timing to 8 deg btdc at idle and 38 btdc at 3K rpm.

i was running the bosch w7dc but substituted new 7333 ngk's since the bosh were fouled.

thanks for all the replies

I'm wondering if you bought new spark plug cables recently. Check the coil wire. Almost all new sets come with carbon core coil wires. A 14" piece of that stuff can have more than 12KV of resistance when you really want zero. If you find that reuse the cable ends and geta metal core coil wire.

[merrill]

hi Dan,
no change in the spark plug wires.

the plugs were fouled because i was turning the motor to check the dwell.   

once i had the dwell "in spec" i decided to install new plugs.

the fouled plugs cleaned right up with some seafoam and an old tooth brush.  I can re use them at a later date.

thanks again
matt

[Benz Dr.]

hi Dan,
no change in the spark plug wires.

the plugs were fouled because i was turning the motor to check the dwell.   

once i had the dwell "in spec" i decided to install new plugs.

the fouled plugs cleaned right up with some seafoam and an old tooth brush.  I can re use them at a later date.

thanks again

Check your coil wire anyway. Most I've looked at were wrong.
matt

[merrill]

hi Dan
checked coil wire, no resistance

thanks again!