Advanced Timing

Hello

I recently rebuilt my 66 Bronco 170 engine, and the machinist's rebuild recommendations are to set the timing and advanced timing. The shop manual only gives the timing, 4 degrees BTDC, but no figure on the advance timing. In general the machinists guidelines are 7-10 degrees BTDC @ 2000 rpm for advanced. Does anyone know what the actual advanced for my engine should be ?

Thanks
Tony

Hi, the machinist is giving you good advice. The engine will run better if the initial timing is set to over 8* before TDC. I feel you can go past 10* BTDC as long as the engine doesn't ping or knock under load. As you advance the timing the idle RPMs will increase, so the ignition tuneup should be finished before you adjust the carb. Good luck

Congrats on yer rebuild and install !
That's exciting (2me) - All New !

Don't 4get, two kindza 'timing' - initial and total:

ci/IgnitionTiming.html

so U might have 10* - 14* AND nother 20* for total equal 32*, 36*. B Ron's got it tho.
Too much total is no good as it creates too much internal heat in the cylinders causing pre-ignition or that
'pinging' sound of "pebbles rattling around in a tin can". U can burn up that 2K$ job just completed, or any motor.
Yup, this is a sensual (senses: hear, feel, smell, see) experience when U R a 'car guy'. (senses for data - being a full scientist).

Howdy Tony.

Yup! more initial timing advance will give you more power and better mileage. BUT, (Don't you just love big butts.) First, I'd want to know- does your engine have a Load-O-Matic ignition? What is the elevation where you live? What transmission is in your car?

If you will look at the addendum in your shop manual it suggests that you advance the initial timing by 5 degrees over stock specs if you live at elevations at/above 3,500 ft.

The "Actual" ideal advance setting for your engine will depend on your circumstances. I would recommend starting with a setting of 7 degrees btc. Drive and listen for any knock. If you hear any try 5 degrees of advance.

Also, make sure that your stock ignition system is working as designed.

Enjoy.

Adios, David

Forgot to mention that I have a Loadomatic distributor and manual transmission. So the procedure would be to set the ignition timing, then check the timing when increasing rpm to 2000, the timing should read something higher like 7-10 degrees BTDC, otherwise the advance mechanism in the distributor is likely bad ? Since the advance mechanism is run by vacuum I assume I would reconnect the vacuum line before checking advance timing, and also while it's off check the vacuum at idle (should be17).

Thanks again
Tony

Howdy Back Tony:

Still missing your elevation. YEs, Disconnect vacuum from the carb while setting the initial advance.

The LoM system works on load. It only advances the ignition when accelerating or otherwise loading the engine. Do the initial advance first, then assess the LoM function. Good Luck.

Adios, David

Hi Tony, if you haven't read about how the unique Load O Matic (LOD) Distribitor Advance System works, check out the sites tech article it should help with your understanding of the system. Good luck

LOD Tech
ci/Loadomatic.html

wanna post him the (your) ign tune & carb tune?

How much of this will you B doing your self Mr. tony? What kindza tools and experience do U have?

You need to get rid of the loadamatic distributor.
However what size oil pump shaft do you have? If yours is 5/16" you can go to the DS11 or an HEI.
The next problem is your loadamatic carburetor. Either have it modified for ported vacuum or get a 68 & later carb.