1951 Pontiac Chieftain

[PhilA]

It sounds like it's trying to take off at 2000 rpm though.

[PhilA]

Had a slight misfire at light throttle.

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Trailing points had closed up a little. Adjusted them back up.
Found a vacuum leak at the carb for the vacuum advance too, repaired that (loose union).

Test drive in a little while.

Phil

[PhilA]

Noticable improvement.

Light throttle feels a lot less strained now, if that makes sense.

Phil

[PhilA]

I did a tune-up.
Set the ignition timing and idle mixture last night. Both by ear and feel but the car is significantly more lively now, and accelerates noticably better than it did.

I'll keep an eye on the fuel economy, that should improve too.

Phil

[Hooli]

With the changes in petrol over the years, I doubt the original settings would be best any more anyway.

[PhilA]

With the changes in petrol over the years, I doubt the original settings would be best any more anyway.

Agreed, the average octane rating of rural fuel was at an 82 average when the car was built (hence the modest compression ratio), since a more unified 89.

It's a shame the distributor doesn't have a vernier adjustment but really that's overkill. You start seeing a change once you've dialed in a few degrees, not a few tenths of a degree.

Would be fun to put it on a rolling road and get it set up.

Phil

[Hooli]

When I get my Bonnie built it'll be running 2 degrees less than standard advance to prevent pinking on normal fuel, plus larger jets. Oh & if can set it up well enough about 5 degree extra advance on the intake cam.

The first two due to engine mods & different fuel, the last because it's known to boost midrange grunt which is where I like to run engines.

[PhilA]

I had this set about 4 degrees advanced. I've since solved a vacuum leak and some other issues that meant dialing it back towards stock made a noticable improvement in mid-range torque.
Being as this is the epitome of a low revving engine, it's nice to have the torque really start to come in around 1500rpm. It should peak at 2200, rapidly dropping off after about 2600.

Putzing about the car spends most of its' time around 1500-2000 rpm on local trips, so having it slightly backed off should have helped but it made it sluggish.

Phil

[PhilA]

Car was running rough after a short drive. Timing had slipped and was sitting on the stop at about 35° BTDC so I set that back to the factory spec 10 degrees.
Tightened it down good and proper.

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Took the dog for a ride, that went down well.

Phil

[PhilA]

New fan belt fitted, this one doesn't slip.

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New light fitting for under the hood, arrived in from Indiana this morning.

Phil