Ignition timing question

[Ed Riefstahl]

Greetings all,

The final step of my tuneup to my 1966 230SL is check the timing. I've read what past posts I have found, which seems to be 30 deg BTDC @ 3000 rpm . I've also checked my repair manual which is the same.

My question is, with or without vacuum? I can't find where it tells me.

Thanks,

Ed Riefstahl
Erie, PA

1966 230SL (Ms Magoo) Horizon Blue
1970 280S (Miss Daisy)
1999 BMW Z3 5 speed
1991 BMW 318I 5 Speed
1997 Toyota Paseo Convertible - One of 1000, (have you ever seen one?)
1997 Ford Ranger step side (Mater)
2023 Mazda CX 5

[Benz Dr.]

Set your timing to 38 degrees full advance with vacuum lines attached. This should give you around 8 degrees at idle speed.

[Ed Riefstahl]

Thanks Dan,
That explains my problem. I have the timing set it at about 10 deg BTDC, at idle, but it is much higher than 30 deg at 3000. When I was a mechanic in the 70's working on American cars, we'd set the timing at idle with vacuum disconnected. I don't recall ever checking timing at a higher RPM than idle.

Ed Riefstahl
Erie, PA

1966 230SL (Ms Magoo) Horizon Blue
1970 280S (Miss Daisy)
1999 BMW Z3 5 speed
1991 BMW 318I 5 Speed
1997 Toyota Paseo Convertible - One of 1000, (have you ever seen one?)
1997 Ford Ranger step side (Mater)
2023 Mazda CX 5

[Benz Dr.]

Should be around 38 degrees at or before 3,000 RPM. It will be around 2,700 RPM on most cars.

[Ed Riefstahl]

I had my wife hold the throttle at 3000 for me. I ended up about 40 deg BTC at 3000 and 10 deg BTC at idle (around 800 rpm). This is where the car seemed to be the happiest. Even my helper (wife) commented that it sounded good.

I meant to check the timing chain for stretch when I adjusted the valves a few months ago, but forgot until after I had it all back together. I really doubt with 60,000 miles on the chain, that I would have very much stretch.

Thanks for your help.

Ed Riefstahl
Erie, PA

1966 230SL (Ms Magoo) Horizon Blue
1970 280S (Miss Daisy)
1999 BMW Z3 5 speed
1991 BMW 318I 5 Speed
1997 Toyota Paseo Convertible - One of 1000, (have you ever seen one?)
1997 Ford Ranger step side (Mater)
2023 Mazda CX 5

[Sead]

Set your timing to 38 degrees full advance with vacuum lines attached. This should give you around 8 degrees at idle speed.

This is with original to 230 nr 46 distributor? Vacuum adv.v
Or later as commonly used nr51? Vaccum ret.?

Thy
Sead

[stickandrudderman]

It doesn't matter whether you have vac adv or vac retard, all cars have 38 degrees at 3000rpm with everything connected.