1966 Bird 390 timing trouble-help!

[66 T-Bird]

Help! 66 Bird w/390 engine when running is shaking, popping, backfiring. I’ve timed it with timing light at the white mark the former owner painted on pulley/harmonic balancer (he marked it at 10 so I took for granted that's where it ran the best) But…I’ve read that it should be 6 or so BTDC. Please look at this pic and let me know if I should try again at 6 BTDC or another number? Also, do you know if Top Dead Center is where it reads “Top Dead Center?” Or is TDC at the zero “0” mark?? Thanks very much for any help here.

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[neilwillis]

while 6 is ok that’s not your problem it would run on any of those settings 6 -8 - 10. etc i’ve had the same problem that turned out to be completely different
don’t assume the carburetter is ok take it off and check the REAR chamber arm is free and working, i know you’ll say it should run on the front two but do it anyway ,
check something so obvious you’ll tell me off but although the plug leads appears on make sure the actual metal tip at the end of the plug leaf is on the plug itself ( sometimes the sheath is too long and there is a tiny gap )
your number one cylinder ( front left) should be at TDC when it points to that on your flywheel
take the plug out turn by hand use a little wooden stick, not metal gently pushed into the plug hole the feel when the cylinder is at the top until this is then is at the top that’s TDC
Now check where your distributer rotor arm is pointing that’s got to be at no 1. cylinder and it’s possible it is dead opposite to where it should be ( diagrammed in manual )
move the distributer cap around ( or move leads around
Neil

 

[66 T-Bird]

Neil - Thank you for this. My carburetor choke connecting rod has a plastic tip inserted into the choke lever. That plastic piece is broke making the choke technically inoperable. I'm looking around for the part to replace that. Do you think that this is what is making the car run like it does? Or would that not affect it? Thanks again for all the help!!!!

 

[66 T-Bird]

while 6 is ok that’s not your problem it would run on any of those settings 6 -8 - 10. etc i’ve had the same problem that turned out to be completely different
don’t assume the carburetter is ok take it off and check the REAR chamber arm is free and working, i know you’ll say it should run on the front two but do it anyway ,
check something so obvious you’ll tell me off but although the plug leads appears on make sure the actual metal tip at the end of the plug leaf is on the plug itself ( sometimes the sheath is too long and there is a tiny gap )
your number one cylinder ( front left) should be at TDC when it points to that on your flywheel
take the plug out turn by hand use a little wooden stick, not metal gently pushed into the plug hole the feel when the cylinder is at the top until this is then is at the top that’s TDC
Now check where your distributer rotor arm is pointing that’s got to be at no 1. cylinder and it’s possible it is dead opposite to where it should be ( diagrammed in manual )
move the distributer cap around ( or move leads around
Neil

also, what do you mean in your statement saying" flywheel?" I thought a fly wheel was on the trans? Sorry if I seem stupid, just not sure which fly wheel your referring to? thanks!

 

[neilwillis]

no think of it as that photo you presented that shows the timing marks

 

[74 Harley]

That photo shows the harmonic balancer, the zero is tdc. You're choke will only have an effect on the running when cold. Your problem sounds like a possible vacuum leak, worn timing chain,or possibly a burnt valve. Is this a new problem with the car? How many miles are on the engine?
It's not possible to run 180 degrees out of time.

 

[neilwillis]

just in case my info seemed odd i was sugesting putting all the distributer and plug siring to look same as in the manual not trying to run 180 deg out of time,
the timing chain also mentioned previously is also likely to and can be checked . remove fan shroud then fan then water pump ( drain first) there are two bolts that go through the water pump part of the timing chain cover

 

[64ZCODE]

Help! 66 Bird w/390 engine when running is shaking, popping, backfiring. I’ve timed it with timing light at the white mark the former owner painted on pulley/harmonic balancer (he marked it at 10 so I took for granted that's where it ran the best) But…I’ve read that it should be 6 or so BTDC. Please look at this pic and let me know if I should try again at 6 BTDC or another number? Also, do you know if Top Dead Center is where it reads “Top Dead Center?” Or is TDC at the zero “0” mark?? Thanks very much for any help here.

Has it run OK in the past? If so, what did you change since then?

 

[BigClay]

Your crankshaft damper (pulley assembly) with the timing marks looks very old and rusty. It’s very possible that the ring/part with the timing marks has “moved” or slipped. I would get a vacuum gauge, hook it up to the intake manifold, and “adjust” (turn) your distributor to get the highest vacuum reading you can at idle. The vacuum gauge needle should be steady and not “shaking”. (If it shakes, you may have valve sealing problems). After doing this procedure, double check your timing marks with your timing light (to see if they have changed). If they have , you probably need a new damper assembly.