He all you real mechanics. I have been trying to trace the reason for the wandering timing marks while trying to get this car to run right. What I did was rotate the crank to TDC and noted the position of the distributor rotor. Then I rotated the crank the opposite way until I saw the rotor reverse direction. It came to be about 12' of crank revolution. This tells me that it's pretty sloppy but what would you think would be the limit that one might see before he had to change the timing set? The other thing I'm not sure of is; there are two vacuum diaphragms on the distributor one goes to a ported vacuum source on the carb, the other goes to manifold vacuum. I don't get the reason for the two. One, the ported one is supposed to advance the timing at start up. What's the other one supposed to do. Thanks!
Still have the OEM carb on it? Ford was in love with all-vacuum-advance distributors in the early 50s and had carbs that were 'calibrated' to the ignition. Swap to a newer/wrong carb, and your timing was out the window. And 12 degrees of 'slop' at the crank could be enough to cause the timing to 'hunt', but a dirty carb, vacuum leak or failing vacuum diaphragm could do the same thing.
What's your timing chain and sprockets like? I would repeat your first test and see if the valves move sooner than the distributor rotor. If they move at the same time then it might be a sloppy timing chain and sprocket.
Do you have a ported vacuum thermo switch in the intake manifold, if so the switch prevents the vacuum timing from coming to play untill the engine warms up, manifold vacuum is applied to keep it retarded to the back of the vacuum unit, if the ported vacuum switch is bad it will cause the timing to hunt
Still got the original carb which I rebuilt. Sprayed carb cleaner around the manifold and didn't detect any leaks
What you are telling me makes sense...but there is no vacuum switch. Maybe it has been removed somewhere in it's history. Another interesting thing is that if I put my mighty vac on the outer diaphragm it doesn't seem to do anything to the pull rod attached to the point plate. The inner diaphram advances the point plate as expected. There is a cyntrifical advance under the point plate to boot.. Nothing in any of my era manuals about this setup
There doesn't seem to be any play in the distributor gear mesh with the cam gear, so don't think this would help.
Could be you are reading a loose damper, I have 3 of the 368s and have had 2 rebuilt. The third needs it but it is just a spare.
2X on the dampner being loose/slipping! Seems to be a standard problem on an otherwise good engine series from the start!
I haven't seen a dual diaphragm distributor on a Ford engine built before the smog era of the 70s with EGR valves but they might have used them earlier. If the crank is turning 12 degrees before the cam turns, you definitely have a timing chain problem. It should be easy to tell if the damper is moving without the crank turning. I assume you are using the crankshaft pullet bolt to turn the crankshaft and the damper would have to be awful loose to show up doing that. As was said, pull a valve cover and watch a rocker arm that moves when you go forward and see how far backwards you have to turn it before it moves again.
Just a side note : '53 Lincoln had a dual diaphragm distributor('52 was a single) that was a real pain to keep working properly(had one ; changed to '52 & improved performance)
The 56 y blocks big & small had the dual diaphragm , at least my 56 merc 312 and all my 56 linc motors do. My 57 that I just sold was a single. I changed the 56 in my avatar to a single
Good thought on the damper....It would have to be real loose though. The reason I'm saying that is that the light is wandering...not the marks on the damper. Not sure I said that correctly. Anyway I have resigned myself to changing out the timing chain. I would have started doing it before bothering you all but the owner dint want to put any mo money in it. Is the 368 considered a y block? Thanks to all
Yes it is a y block. A rather unique one without much that interchanges from what I'm finding. I have mine on a stand right now resisting opening it up "just to check" due to cost of parts. Pulled it to address leaks on steering box, trans, and rotten soft plugs. Runs good all told so going minimal route. Spring time driving is close! Posted using the Full Custom H.A.M.B. App!
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