Skipped timing? Bad engine vibes!

[Anonymous]

Ok, here is the whole story before I get to the issue. A while back I had a problem with my ignition. The main wiring harness to the engine fried together and made the car run rough. It idled hard and refused to go or run correctly. I fixed that problem and the car runs now, but there is a vibration from the motor. The car did backfire a number of times when it was running rough. Now when I rev the engine, there is a vibration in the car. This happens when the car is in park and sitting still. As the revs increase so does the vibration. Is it possible that the engine skipped time, and how can I check this? I have looked on here and haven't found any posts about this. I saw that someone recommended checking the valve adjustments to someone else. I will check that tommorrow. Anything else I can check to diagnose this vibration. Would the engine run if the timeing gears were off by a cog or two? This is a 66 mustang 200 with a c4 auto. All stock, no changes.


Jon

 

[mugsy]

If you think the timing chain has skipped a tooth you can tell by a vacuum gauge/check. My '65 idled with about 21 in. Hg. I knew someone who had drivability problems with a Jap truck that she just bought. To make a long story short the timing belt was put on a tooth off by the previous owner. The engine ran with real low vac.

 

[Anonymous]

I have had vac problems as well. I was wondering if that could have been the problem, since the dizzy didn't seem to advance properly. I also plan to check the vac advance to see if it is good.

Jon

 

[plastic-idol]

I've had the same problem with mine. It's been in and out of the shop for a month. Pretty much my whole electrical system was shot, from voltage regulator to dizzy to alt.

 

[Anonymous]

Did your car have the harness short out first and that caused the problem? I also had my tranny rebuilt recently and I was thinking it could be the torque converter, or flywheel being out of balance. Did you replace the coil and everything. The starter, solenoid, battery, and engine harness are new. I also have a automatic fuel pump, it operates at 3-5 psi. I just rebuilt the carb this weekend, to see if that was it, but the vibration is still there. I set the float correctly, and retuned it. How would I know if the dizzy is bad, and what else could I check

Jon

 

[addo]

For all the shocking wear it can show, I've yet to see a Ford timing chain actually skip.

As to the dizzy. How to check for wear: If it's a dual advance unit, pop the cap and "tweak" the rotor in the direction of rotation. Movement is about 3/16 or so at the tip. You should feel a springiness that returns the rotor to its pre-tweaked position. This will tell you if the return springs are working. It won't ell you if they're aged and losty tension. For either type, now pull the rotor button, grasp the metal shaft firmly and try to pull/push it. Play should be about 30 thou. Less is a problem, as is more.

Disconnect the vacuum line from the diaphragm now. Push-pivot the breaker plate towards the diaphragm, simulating the effect of vacuum. The movement should be smooth and not at all sticky. It should snap back instantly when released.

A vibration in the motor running (as in rough running) could be head-related isues, like a burned valve, bent stem, worn lobe, sticking lifter, eroded seat. If you have a vacuum only dizzy then these aspects of rough running change the factory ideal vacuum to the dizzy, and the whole thing starts to fall in a heap. Compression testing will reveal any anomalies here.

As to transmission imbalance - has been known. With the inspection cover off, you could try strobing the fleaxplate/TC with a timing light. A wobble might show as ghosting. For safety, this is a two-man job!

Regards, Adam.

 

[Anonymous]

Backfiring thru carb is a lean condition or timing issue. One thing you may want to check is to make sure you are at TDC when your crankshaft balancer says so. With age, the rubber can disbond and the ring can slip. It happened on mine, and if I timed it by ear, I could get it to run smooth. If I used a timing light, it was no where close to running right. I verified that the ring had slipped in relation to actual TDC and replaced the balancer. Was able to time correctly after replacement.

 

[MustangSix]

A skipped tooth on a 200 timing set is a rare occurance which would probably be followed by other expensive noises. Unlike 300's which had fiber gears, or some other engines with plastic/nylon, the 200's gears are all steel. A chain loose enough to jump would be slapping around all over the place, eating the heck out of the timing cover.

From the symptoms you describe, it sounds like you have one cylinder not firing. Isolate that cylinder first. Run the engine, pull one plug wire at a time until you find one that is not making any difference. Then isolate the cause - plug, plug wire, cap, burnt valve, etc.

 

[Anonymous]

I have corrected the problem that initially cause the car to backfire. It no longer does that. I checked the vacuum on the engine and it is right, so I don't think that it skipped a tooth on the gears. That was just a question. I did check and see if the vibration I have was a cylinder not firing, but that isn't the case either. When the car is running at idle, it sounds fine, and idles very smooth. When I rev the engine up, the vibration begins somewhere around 1200 rpm and becomes faster with the engine. So far I have rebuilt the carb, regapped all the plugs, gapped the points, and re-timed the car. I have pulled the plug wires one at a time and they all act the same. I had the trans rebuilt right after I bought the car in Nov., and I don't remember this vibration before it was rebuilt. That was where the question of the Torque Converter/flywheel came in. I know that there was not any vibration before I bought the car, but it had the electrical short on my drive home that resulted in towing the car 150 miles home. That was fixed and then the car had the trans rebuilt and a new Torque Converter was put in at that time. It was after this that I noticed the vibration. The mechanic that did the rebuild said he thought it was a timing issue, but I think I have eliminated that as a possibility. Any other ideas?

Jon

 

[MustangSix]

Could still be an ignition issue. One plug not firing at any speed above idle due to weak spark, extremely worn distributor, etc.

Bad torque converter could be the culprit.

 

[kirkallen143]

I know this about flex plates and the 302 V-8 engine, there were two different balance weights. Maybe got wrong flex plate installed? Also check your water pump, could the bearings be out? This happened to a Chebbie of mine. The harmonic balancer is also a good place to start. Good luck.

Kirk Allen Jorden ' 73 bronco