Best way to time an engine

[Guest]

I'd sure like to find the sweet spot for my Studes and always seem to be fiddling with finding it. I know the manuals address it, but now 40+ years later, is there a timing light and/or process you swear by rather than at?
I'd sure appreciate any advice. Thanks!

[PackardV8]

Hi, Tom, assume you are beginning with a rebuilt distributor and all new service parts. Recently, I've had to tell one owner with a worn Prestolite there was no way to help his timing problems externally. Another Delco owner had a bad vacuum canister. The third had dead plug wires and a cap which was arcing internally.

Once there is a rebuilt distributor with vacuum and centrifugal advance curves verified on a machine, new points, condensor, rotor, cap, plug wires and plugs, then serious on-the-car power timing can be undertaken,

FWIW, I start with a full tank of whatever fuel I'll always be running and the initial timing set at factory spec. There is a steep four-lane hill outside town which is nearly a mile long. With engine oil and water at full operating temp, I start on the flat, stabilize my speed at 30 MPH in direct 3rd (overdrive locked out) or 4th gear (yes, an automatic complicates things. Whether it will downshift depends on the rear gear and the adjustments of the linkage.) and floor it as the hill gets steep. I use a stop watch to record how long it takes to go from 30-65 up the hill. Then, I pull off, open the hood, use the timing light to advance the timing one degree, repeat the test. When pinging is heard and or no further decrease in time-to-speed is found, I back it up one degree and that's where I leave it.

.)

thnx, jack vines

PackardV8

[Mike Van Veghten]

The way I do it....
I give the engine what IT...wants. Not what I want, someone else thinks or some book tells me it should have.

While it may take some driving time, I also work on the vacuum and mechanical advance this same way...it's to keep playing with the timing while noting the seat of the pants feeling and the milage.

If you have a drag strip handy...THAT'S the best way to find it fairly quickly...one afternoon.
Anyway, I'll make a guess, sometimes by the engine sound, sometimes by the highest vacuum gage reading..then put some miles on it, note the gas mileage. Add 3 or 4 degrees, repeat milage test. Also note seat of the pants dyno.
NOTE: the carburetor needs to also be set correctly. It is afterall, part of the whole.

When doing the whole thing...it can take some time (weeks, months). When doing just the static timing, a coupla longish (30 or 40 miles) trips to check the power and milage should do.

THAT...(or a chassis dyno pull or two will get you close also) is the only (3 ways) to get your sweet spot.

Nice to see someone that realizes there's more to this than just what the "book" says.

Have fun experimenting.

Mike

[bige]

Simply to add to the proper advice given in the first two posts...

The 'butt dyno' can be deceiving. Too much advance will feel great off the line but keep the engine from developing higher rpm power so any road tests should really be through the full rpm range and at least to the top of second gear.

Bringing the engine up to 2500-3000 rpm in park or neutral in the driveway and holding it in that range can indicate too much total advance. If you note a slight miss or stumble at a steady, higher rpm you may need to back things down a little, or adjust total centrifugal advance or change the amount of vacuum advance.

Try starting the engine after it's been driven for awhile and see if it cranks easily or is it labored. Labored means too much initial advance. If it spins quickly but doesn't light off right away you're too retarded.

And of course audible pinging probably means your total advance at the point of ping is too much.

ErnieR


On its way to a 15.097 Island Dragway Great Meadows NJ Spring 2006.

[studegary]

A lot of good information above. I start with by the book timing light timing. Even this doesn't always give a good starting point. I remember one Pontiac V8 that was driving me crazy until I discovered that the harmonic balancer had shifted and made the timing mark incorrect. On pre-catalyst cars, I also use the exhaust as a guide.

Gary L.
Wappinger, NY

SDC member since 1968
Studebaker enthusiast much longer

[Guest]

Great info, thanks. Much test driving ahead for me.