Can you give me some feedback, my 292 sat for 15 years and I have no idea if the damper is original or not. I do know the 292 is the not the original block but a rebuilt (.040" over) long block in the late 80's. Anyways the thing runs like a dream, but I can't get the idle down below 900 RPM. Timing is theoretically about 10 degrees. Vacuum at a solid 20". If I retard the timing I can slow the idle down but then I loose vacuum. My understanding is Vacuum is king, but maybe I'm wrong. One thing I noticed when I retard the timing is that my Y block sounds fantastic with a super nice lope. So I'm really stumped on my timing / idle. 1850 Holley is fresh rebuild.

 

When using a gauge advance the ignition timing for max vacuum yes but then, ya hafta back it off at least 1 full inch of vacuum indicated on the dial. Make sure the vacuum advance hose is disconnected and plugged. Also ensure when you hook it back up that it is connected to ported vacuum, not manifold vacuum. Use a tach unless yer ears are calibrated good.

You probably won't be pulling 20 when you get everything set right, to include idle RPM, and idle mixture. Still, by doing this you'll be able to adjust the idle RPM to spec (500-550.w/ manual xmsn) and then, adjust the idle mixture screws for the maximum vacuum and smoothest idle. (Aka "super nice lope"!)

As you get the idle mixture settings dialed in you'll likely have to decrease the idle RPM setting. Holley's might like thing set a little higher - maybe 600 or so. Timing, as you have noticed affects idle RPM, and so does the mixture settings, they all affect each other so you'll have to go back and forth a bit. Make sure the throttle isn't sticking or binding, it has sat for a long time? Making these adjustments correctly will give good performance and best economy.

Make sure your float level is correct too, and check to see that the throttle plates are perfectly vertical when pedal floored (engine off) engine warmed up before you start all this, etc. - and you'll get to listen to that Y block music all the time!

Sent from my iPhone using IB AutoGroup

 

Thanks!! This is just what I was hoping for.

 

Whoever gave you this BS info...didn't have a single clue what they were talking about. The inner damper of the harmonic balancer is bolted to the crankshaft.

At the factory, a rubber gasket is placed between the inner damper and the outer pulley, then the three parts are pressed together forming a one piece assembly.

Over time, the gasket age cracks/shrinks, causing the outer pulley to begin to "walk away" from the inner damper.

If not noticed, the pulley can fly off the damper taking assorted belts and etc along with it...may end up in the radiator core. Not pleasant!

 

Thanks for clarfying that. My source was a vender who rebuilds Dampners, including Y blocks. I was trying to make it clear in my post that I was hesitant passing along that information. Looking at the Y block Dampner, I did not see anything that would keep it from going either way.

 

I agree with everything Tedster said when using a Vac gauge. I'm wondering do you have or know if you have the stock cam? If you have a "bigger" cam you may not be able to get your idle down altho pulling 20" hg suggests that it's not (bigger).

Also check for vacuum leaks, i.e. intake, carb base, etc.

 

There were quite a few variations on the dampers throughout the years and any one of them could be on a Y block at this point. On some, it is the pulley that can slip. On others it is the damping mass which is behind the pulley and can only move toward the timing cover - I have 4 examples of this one in the garage. There is no way the mass will move toward the radiator but it can still do good bit of damage if it gets loose. That vendor is correct for some Y block dampers.

 

Still when they slip off their index it's obvious the vibration damping isn't what it should be...

Sent from my iPhone using IB AutoGroup