Spark timing question

steamgas

steamgas

Senior Member
i know this question has been asked before but i need to know where to go to get the information i need. my rebuilt engine runs good but i need to now set the spark timing. i know it has an adjustment on the side of the distributor but before i do anything i need to know what i am about to do. can someone please direct me to the information i need? this is a 1935 ford Flathead engine with the distributor on the front of the engine
 
The easy method is to hook a vacuum gage to the intake manifold. Advance the timing to get the highest vacuum reading at idle speed. Back off the timing a little. Road test by going up a hill in high gear. If the engine pings, back off the timing until it does not ping.
 
FritzJr said:
The easy method is to hook a vacuum gage to the intake manifold. Advance the timing to get the highest vacuum reading at idle speed. Back off the timing a little. Road test by going up a hill in high gear. If the engine pings, back off the timing until it does not ping.
Click to expand...

This is the method I use as well. Most of the engines I run are modified to some degree (heads, carbs, maybe a cam), so the factory settings may no longer be applicable. I have found that this vacuum gauge method has served me well for many years. Just make sure you disconnect and plug the vacuum advance when doing this.

Please be advised that this will only give the best setting at idle under no load. If the distributor is incorrectly curved, everything goes out the window at speed and under load.
 
Point adjustment (dwell) = engine timing. For each degree of dwell timing is off 2 degrees. I would have the distributor built, set up on a running machine and install with no adjustment. The slide adjustment is 12 degrees 6 retard and 6 advance (not much of adjustment......Henry wanted it that way...
 
I had a similar problem. I have a '35 but am running an 8BA. I wanted it to appear to be a '35 motor so had my engine builder make the front of it 8AB style with a crab style
distributor on it.(Hind site 20/20 a mistake) Anyway my builder neglected/forgot to put the timing indicator scale & didn't mark my crank pulley that Jim of Bubba's speaks. So same situation but worse. Mine has an electronic 3 bolt with no vacuum advance. Didn't feel like going thru ag's to remove the head on #1 cylinder side & finding top dead center by bringing #1 piston up to gauge set with an indicator which is what the correct thing to do is and then mark your crank pulley & mount a purchased or fabricate a scale with that pulley mark centered on it. Then with a timing light its easy to set. At the time that seemed like lot's a work to get it running and take a ride so, I remembered as a kid (pre 15) getting them running without any of the techy tools we use and used to have one a buddy trying to start it with me rotating the distributor back and forth til it started. Then while running similar to the vac gauge method just listening to increase and decrease in rpm & going with the highest rpm as a start. Then the hill trick Fritz mentioned under load and a little adjust advance or retard (before schooling I found perf. engines liked a little more advance and stocker's a little retard). Got pretty good at gauging the first time after a while. Then went to a motor shop course in high school and used all the fun tech toys. I guess with a little luck and a little ole school my '35's been running great, I did mean to go back & do the whole correct resolve with the scale mounted and pulley mark but it has run great ever since ( timing wise ) and never went back to it to date 5 yrs & counting. If the electronic Dist craps out I'll revisit setting it up with a crank pulley mark and a scale the correct way (:
 
Remove #1 plug, crank engine while holding your thumb over #1 hole. When you feel the "puff" = compression stroke, both valves are now closed. (Now look down at your flywheel pulley is there a bump or a mark on it? Is there a pointer on the engine ?)
I know an old guy who would put a pencil in the spark plug hole, eraser touching piston, and while pinching the pencil at the spark plug hole after establishing "compression stroke" as stated, had someone hand turn the engine and by feeling the position of the pencil was able to determine the highest position of the piston on the compression stroke=TDC
Country folks, country ways... This is best done when you are under a shade tree. Chap
 
I wonder ...

When Ford started building the new V8 back in the early 1930's, how was the timing set on the engines?

How did the folks who built the distributors set them up? There were no Sun type machines, were there? Some type of KRW fixture?

Do you think they just set the points with a feeler gauge and the advance index to a predetermined spot on the scale?

Did they run the engine and put chalk marks on every engine's crank pulley?

Maybe they held their thumb over the number one hole ... ;)

Did they send them to Bubba?:D

Seems like they must have had a way to set the timing.

Well ... that's your homework. (At least, think about it. No guessing or speculating.)
 
:D As it's been running great for a few years & I won't touch til required (if it ain't broke don't fix it). So if / when I get back to it, from my research it seems the only way to accurately place / mount the center of the 12 degree scale on the engine centering it on the predetermined mark I put on the pulley (mine has no mark bump of any type) is to accurately gauge the top of the piston stroke with an indicator to determine true top dead center. Doing less is doing by estimate anyway and in fact pretty much how I got it running as well as it is now. I have in fact marked the pulley and made a mark on the engine next to it now(as it runs so well now) intending to use it as a reference to see how close I was with the RPM method I used as I did when a kid, just to see how close it is when I get around to using the indicator method. :)
 
You don't need a dial indicator to determine TDC, head on or off. A dead stop is the preferred method. With the head in place an object of your choosing (something firm enough to not deform and soft enough to not do damage) is placed through the sparkplug hole into the cylinder. This would not be a pencil! :) The engine is turned (slowly and carefully) until it firmly contacts this stop. With a pointer attached to the block, the position of this pointer is marked on the crankshaft pulley. The engine is then turned in the opposite direction until it again contacts the stop and a second mark is made on the crank pulley. Note: as with any procedure of this type, this procedure must be repeated a number of times to assure a consistent set of marks. Half-way between the two marks is TDC. This is not some half-*** guess method, if preformed properly it will determine an accurate TDC.
 
Do you think they just set the points with a feeler gauge and the advance index to a predetermined spot on the scale?

I have owned two KW Ignition Testers and i can tell ya if you built 100 distributors and set the slide in the center mark, all 100 would be correct !!!! I dont use them at all any more just check the unit dwell and timing location on a electronic distributor machine....
So i be when the factory received the distributor from the ignition section it was bolted on and never again tested.......
 
It is a lot of work, and it will probably cost you a cylinder head gasket, but you could remove the head. That would make it a piece of cake to determine TDC, would it not?
 
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