Hot Rods Ford Y Block timing issue

Hi
I have a 56 thunderbird with a 312 y block.
I'm having confusing timming issues, if I set initial timming by a light say at 10 degrees it's very hard starting and has big time hesitation.
If I set it with a vacuum gauge it starts great runs fine and doesn't ping, then I check it with a light and it's 35 degrees advanced at idle. Wich would put it somewhere around 70 at 3000 rpm doesn't make sense.
Yesterday I checked if the vibration damper slipped, I brought it up to TDC and the damper showed tdc. And yes I'm timming it off the number one plug.
When it's way advanced like that it runs fine but something isn't right.
Any thoughts greatly appreciated , Tom

 

Worn timing chain?

Pull the dizzy cap and watch the rotor as the crank is gently turned back and forth with a wrench on the crank bolt. Major delays of rotor movement after crank has started to turn indicate pulling the timing cover for a closer inspection might be worthwhile.

Ed

 

I would set it so it runs well. That's how I set all my cars up.. My present 454 likes 20 initial with 16 mechanical no vacuum... Don't get caught up on one size fits all generic tuning numbers for the masses..

I always check the chain on any old motor I buy. I usually just buy one and put it on. Get the factory close link style, not those big heavy double roller deals...

 

Distributor off one tooth?
Distributor shaft worn?

Put it at #1 TDC and check that the rotor is pointing at the #1 terminal on the cap.

I would have said your damper has slipped but sounds like you verified that .


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The vacuum gauge is telling you what timing it wants, just listen to it. Don't try to force it to respond to what the light tells .
My dad showed me that 60 years ago. I still use it on my old cars unless it's my race car and then I use the light and my e.t. slips to adjust timing and carb jetting.

 

Thanks guys.
I didn't mention it has a new chain and cam.
I'm in full agreement with the vacuum gauge method, I'm just trying to figure out what is off. There is no way this thing should be idling at 35 degrees advanced and doesn't ping or kick back against the starter. When there is a discrepancy this big I try to figure it out.
Thanks, Tom

 

Are you sure, you got right cylinder where to measure? In y block number one is front passenger side. Also do you have adjustable timing light? Maybe adjust knob is wrong position.

 

If you are using the stock distributor and carburetor, the vacuum line from the carburetor to the distributor
should be disconnected and plugged during the setting process.. Full advance of 38 degrees at 3000 rpm's should be about right.
Ernie

 

Is it ACTUALLY 70 deg at 3000 rpm, did you measure it?

 

Is the vacuum advance plugged into the ported vacuum as it should be or into manifold vacuum which is what it sounds like?

 

just asking the obvious, is this where you set the timing marks? From memory they are 12 pins apart. Though I doubt it would even run if the marks were lined up opposite each other.

 

^^^^^ Yes!

 

If you think the damper ring has moved. Damper Doctor in Central California turns them around in a day. About $150. They come off pretty easy, at least mine did.

 

Sounds a little like the measurement one might have at a fast idle with vacuum advance connected, and a fast idle. This will not hurt anything and will not particularly be a factor at anything off idle.

If starter kicks back at 10 deg. initial, it isn't going to get any better with more timing, so something is off with the way you're measuring. Disconnect and plug the vacuum advance port. Set the idle RPM to about 450 or 500 when setting the initial. Then spool it up and see where it tops out at. Y-Blocks like quite a bit of timing. 36 would be good, maybe more.