View Full Version : Ignition timing
04-19-2011, 09:00 AM
Just finished installing new plugs, wires, cap and reset timing to what I thought was factory specs but still getting backfire through the carb with acceleration. What is the best setting for the timing on a '60 with a stock 352?
04-19-2011, 09:53 AM
The initial timing is 6 degrees BTDC. This is set with the vacuum line disconnected and plugged. The manual has a table of centrifugal advance points that you can easily check with a dial back timing light also with vacuum disconnected and plugged.
The vacuum advance is another issue. If you have an old distributor, more than likely the diaphram is ruptured and you aren't getting proper vacuum advance which would be a problem under load. Once you have determined that you have a good diaphram and a mechanism that can easily move back and forth, you can measure the vacuum advance using a vacuum pump to pull the specified vaccum and you can test at the points listed in the table in the manual.
Both centrifugal and vacuum advance are adjustable. I believe the FE engine folks are looking for 38 degrees total advance which is the intial timing plus the centrifugal advance.
Richard D. Hord
04-19-2011, 10:14 AM
When I first started working on this timing issue with Christine, I went through the same problem. Some of the guys told me to buy a timing light, so I did. I had replaced the plugs, plug wires, rebuilt the carburetor, installed new distributor, new vacuum advance and installed Pertronix system in distributor! Set timing according to manual and she would pop and carry on like crazy. I checked everything several times with no success! So I searched through some of the old post and found that the index mark on the crankshaft damper could be off with the piston and also timing chain wore. Dave Dare (simplyconnected) will be able to explain this in more detail! Anyway I ended up setting my timing by ear! You set it, drive it, set it, drive it and so on! I got it set and now I have no problem starting her and she runs fine!
Richard D. Hord
04-19-2011, 11:26 AM
It's very common to find that the timing marks on the balancer have slipped. I've had success using a vacuum gauge. Once you have the idle speed at specification, rotate the distributor until you get the highest vacuum reading. Reset the idle speed again as it may have changed. Now rotate the distributor again to the highest reading and then back off 2" of vacuum. This will put you in the ballpark and after driving you may want to make minor changes to correct spark knock.
04-20-2011, 08:40 PM
We need to get someone to write up steps for locating top dead center (TDC) then have a bunch of us collect information on how much each person's was off.
Another area that needs consideration is wear in the distributor shaft. If the bushing(s) are worn, you can get erratic/inconsistent timing results - up to 5 degrees of variation in my case years back before I figured out what was wrong.
Bottom line: if you go the degree route (vs vaccum or trial and error), you have to check all your components out first or all the numbers may be meaningless.
On the high end, there are more dynos available than ever and for $75/hr or so you could put your car on one and play with the timing until you optimized things. Since timing is quick and easy to change, you might make some terrific gains in a short time.
04-20-2011, 09:11 PM
Finding TDC is not too hard, all you need is an 18 mm X 3 inch bolt and some chalk. Take out # 1 plug and bring the engine to about 30 degrees BTDC then wind the bolt into the plug hole till it stops. Back the engine up a bit then advance it in rotation untill it touches the bolt, then mark the damper with chalk at the pointer. Now back the engine up almost a whole rotation until the piston touches the bolt again and mark the damper. Measuring carefully, split the difference between the two lines, that is TDC. I would unhook the battery while doing this, if the starter were to engage it could get ugly. This method is common when checking cam timing. Hope this helps, Bob C
04-20-2011, 10:10 PM
OK - good procedure. So we get 10 guys from this forum together and everyone checks the accuracy of the mark they have and report back. One way or another we learn something.
A local guy with a TBird and FE motor found his to be a couple inches off . . .
04-21-2011, 12:43 AM
recheck your firing order. FE's seem to like a little more initial timing than the factory specs. Try 10-12 degrees. Always a good idea to make sure tdc is in fact tdc. Mike
04-21-2011, 01:37 AM
Ford always seems to put the timing marks on the urethaned damper pulley instead of the solid V-belt pulley.
I use a three cornered file to form a 'nick' on the edge of the V, then paint it yellow. The original TDC mark is still visible, but now I have a solid reference if it ever moves.
This 'piston stop' tool is easy to make if you have a welder. Just bust out the porcelain in an old spark plug and weld a 1/2" rod in the middle that sticks out 2". It doesn't have to be fancy and it doesn't matter if the thing is off-center.
Another tool that is handy is a busted-out spark plug with a male hose connection welded on the end for a quickconnect hose coupling. Use it to check leaky valves and to change valve springs while the heads are still on the block. Believe me, if there is any kind of leak, 60-psi sounds very loud in the carb, exhaust manifold, or oil filler spout/draft tube (coming from the bottom of the block). - Dave
04-23-2011, 07:17 PM
Thanks for the suggestions. I have the timing set now at what looks like maybe 14 - 16 degrees and it runs great and without backfire.
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