Flathead timing question

[HOTRODPRIMER]

I drove the mor-dor to Cherokee, North Carolina this past week-end for the Tribal rod run,,,,,,,,great weather,trees changing color and the flathead ran great,,,,,except,,on the long winding up hill climb of about 3 miles,,,,,,the damn thing started to spark knock like the timing was off.

This is the same flathead that runs 160 degrees in bumper to bumper traffic,,,,,,,goes like a bat outta hell,,,,never a problem until now,,,,heck ,i may not even have a problem
this was just a noise i am not comfortable with,,,,,,after i was off the steep grade the death rattle went away.

Is it timing or what? or am i expecting too much to think that i will ever be able to hall ass up the mountian a little faster than a ol' VW bus,,,, http://www.jalopyjournal.com/ubbthreads/images/graemlins/confused.gifHRP

[Deyomatic]

You might want to retard it a hair and try again.

[Bruce Lancaster]

What type of flathead and what distributor?

[286merc]

Could just be some poor gas. Or go up a grade in fuel the next time the mountains call.

Flat head octane requirements are roughly 2 to 2.5 points higher than the same cr in a generic OHV. So that means a bone stock 7 something cr may need a 89 octane at times.

[HOTRODPRIMER]

The flatty is a 48/49 block with aluminum heads and a 4 barrel carb and i'm using a dual point distributor and always run highest octane gas,,,,,,HRP

[Bruce Lancaster]

What kind of distributor? Is it a recent Mallory? Many of them have a SBC timing curve with WAY too much timing for a flathead.

[HOTRODPRIMER]

Yeah,it is a Mallory,,,,,,,probably 6 or 7 years old.

[Petejoe]

You could also look at the loss of oil pressure. Dirt may have temporarily been giving you that death rattle from the lack of oil. Check your screen at the pump and your oil level of coarse.

[warbird]

Watch out for the Mallory's, they periodically get some bad press on the Fordbarn message board. As Bruce says, they come with way too much total advance built in and you need to cut it back some.

warbird

[HOTRODPRIMER]

I'll try retarding the timing a little,,,the oil pressure is always strong!!!HRP

[286merc]

48-49?? I take it that means the 8BA style block?

If so it sounds like one of the early imports, you never knew what you were getting for a curve.
Also Mallorys are known for bad condensers; if it is partially failed you will have less spark.

[swissmike]

I had the mystery noise for a long time until I figured out what it was. I had to retard the distributor (crab style Mallory dual point) as far as the oblong holes would allow until the knock went away. I am afraid that I don't have enough advance at low rpms.
Is there an easy way to correct the advance curve ( changing springs or weights)?

[warbird]

Hope this is still active-

http://www.btc-bci.com/~billben/mech-adv.htm

warbird

[swissmike]

thanks warbird!
this is exactely what I was looking for. I will try it out once I have my carburators sorted out again..