10BTDC is the line AT the 10. Where is your’0’ TDC mark on balancer? I see a bunch of lines in your picture. You need to mark the TDC line on balancer with chalk or white grease pencil.
My untimeable motor.
- Thread starter DynaBro
- Start date
DynaBro
Well-Known Member
It's a bright white line under that black line and piece of tape at the very bottom. I placed some tape there with another line at 2.36 inches counterclockwise from the TDC mark to attempt total timing.
dvw
Well-Known Member
If the idle speed is close to what it was set at the issue is inside the distributor. What this video for disassembly
Doug
Doug
DynaBro
Well-Known Member
I did the math and verified it with Grok. At 3000RPM the 2.36 inches counterclockwise from the TDC mark should align with TDC.
DynaBro
Well-Known Member
Very informative.
MoparLeo
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To verify TDC, Use the piston stop method and mark the Harmonic Balancer.
This will establish true TDC without removing the head and using a dial indicator.
Also check the Harmonic balancer for slippage between the inner and outer sections.
This will cause extreme swings in the timing marks.
AI Overview
To find Top Dead Center (TDC) with a piston stop, install the tool in the #1 spark plug hole, then rotate the engine by hand until the piston stops the tool, marking the harmonic balancer. Rotate the engine in the opposite direction until the piston stops the tool again, and mark the balancer. The true TDC is located exactly halfway between these two marks.
What You'll Need Piston stop tool (threads into spark plug hole), Socket wrench and spark plug socket, Marker or chalk, Harmonic balancer and timing pointer, and Hand or socket wrench to turn the crankshaft.
Steps to Find TDC
1m
Summit Racing
YouTube · Dec 19, 2013
Important Tips
This will establish true TDC without removing the head and using a dial indicator.
Also check the Harmonic balancer for slippage between the inner and outer sections.
This will cause extreme swings in the timing marks.
AI Overview
To find Top Dead Center (TDC) with a piston stop, install the tool in the #1 spark plug hole, then rotate the engine by hand until the piston stops the tool, marking the harmonic balancer. Rotate the engine in the opposite direction until the piston stops the tool again, and mark the balancer. The true TDC is located exactly halfway between these two marks.
What You'll Need Piston stop tool (threads into spark plug hole), Socket wrench and spark plug socket, Marker or chalk, Harmonic balancer and timing pointer, and Hand or socket wrench to turn the crankshaft.
Steps to Find TDC
- Disconnect the battery: and remove the spark plug from the #1 cylinder.
- Thread the piston stop tool: into the spark plug hole until it's hand-tight.
- Rotate the engine by hand, turning the crankshaft in the clockwise direction.
- Watch the timing pointer: for the harmonic balancer.
- Stop rotating: when the piston makes contact with the stop tool.
- Make a mark: on the harmonic balancer where the timing pointer lines up.
- Rotate the crankshaft in the opposite direction: (counter-clockwise).
- Repeat steps 3-5: rotate until the piston makes contact with the stop tool on this side and make a second mark on the balancer.
- Find the midpoint between the two marks: by measuring the distance and dividing it by two.
- Rotate the crankshaft until the pointer aligns with the midpoint: you just calculated. This is your true Top Dead Center (TDC).
1m
Summit Racing
YouTube · Dec 19, 2013
Important Tips
- Never use the starter motor: to rotate the engine, as this can damage the piston.
- The piston will hit the stop tool twice per engine revolution (once on the exhaust stroke and once on the compression stroke). You're looking for the compression stroke mark.
- Once true TDC is found, permanently mark the balancer with a chisel or punch for future reference.
PlymouthMakesIt
Active Member
The most likely things that will cause timing to jump around are:
1. Sticking advance weights. Make sure they're free.
2. The MSD box is either not getting a clean signal from the pickup or the 6A box has a defect that is causing it to inconsistently read the signal waveform. This can be explained by a defective box (very common unfortunately,) by a bad diode in the alternator injecting AC into the system, or by a pickup that isn't producing a consistent signal. Also, ensure you are not using unshielded plugs and wires with your MSD, even without MSD they will cause a cheap timing light to go haywire.
3. The oil pump shaft is slipping. It's very rare but I've seen it happen. The way you describe the timing walking around after the engine revs makes this more plausible however. A bad bushing could cause the shaft to wear down.
The first thing I would try is to find a known good distributor, preferably one with points since it's the simplest and will be unaffected by most electrical gremlins. If the problem persists the issue is almost certainly a slipping shaft and you will probably need to rebuild the engine. If that fixes it, you need to sort your ignition system.
1. Sticking advance weights. Make sure they're free.
2. The MSD box is either not getting a clean signal from the pickup or the 6A box has a defect that is causing it to inconsistently read the signal waveform. This can be explained by a defective box (very common unfortunately,) by a bad diode in the alternator injecting AC into the system, or by a pickup that isn't producing a consistent signal. Also, ensure you are not using unshielded plugs and wires with your MSD, even without MSD they will cause a cheap timing light to go haywire.
3. The oil pump shaft is slipping. It's very rare but I've seen it happen. The way you describe the timing walking around after the engine revs makes this more plausible however. A bad bushing could cause the shaft to wear down.
The first thing I would try is to find a known good distributor, preferably one with points since it's the simplest and will be unaffected by most electrical gremlins. If the problem persists the issue is almost certainly a slipping shaft and you will probably need to rebuild the engine. If that fixes it, you need to sort your ignition system.
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DynaBro
Well-Known Member
Fair. And there's none of that going on. In fact it runs pretty smoothly but nor correctly. New distributor arrived today so hopefully I can get that installed this weekend and narrow this down. MY friend has a brand new MSD 6AL I am hooping I can simply plug into my existing MSD harness and test that theory.
padam
Well-Known Member
Swapping parts is one way to go about it, but really not a good way.
You need to do a proper diagnosis to find the cause.
DynaBro
Well-Known Member
There has been a new discovery. The crank bolt is oversized. I don’t even know how big yet because the largest socket I have is 1 1/8. Guessing 1 1/4. Balancer is not oversized but it does have balancing holes along the edges.
padam
Well-Known Member
You really need to ask yourself why that would affect timing
DynaBro
Well-Known Member
If it has a stroker kit I didn’t know about, and the previous owner certainly didn’t know about, and it has a distributor for a 383, I think that’s pretty obvious. For reference this car barely shifted when I got it and the guy I got it from didn’t know anything or care. It was stored and neglected other than cosmetically. Every piece of the motor was leaking, both gas and oil. I am not even shocked if this ends up being the case.
DynaBro
Well-Known Member
.
No looks like some over sprayed paint over grime that simply fell off.
DynaBro
Well-Known Member
God no. The entire motor needs a serious power washing. Honestly I want to pull it and either replace it with a nice fresh one or if this turns out to be good news, clean up, do the necessary repairs, nice and repaint.
There is a recent discussion elsewhere on FBBO. See below for my response for my 1970 Charger with a factory 383 magnum:
Post in thread 'Correct Socket Size for '71 383 road runner Harmonic Balancer "Goldilocks" Bolt?!?' Correct Socket Size for '71 383 road runner Harmonic Balancer "Goldilocks" Bolt?!?
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