1955 Olds engine at idle

[lawrence]

I just purchased a 1955 olds 88 that drives well , but has a bad miss at idle. Has new carb, timing is set at the middle mark on balancer, Vacuum gauge fluctuates badly between 8 and 15 inches at idle. Manual indicates that could be late valve timing. Does that mean a bad timing chain or some thing else in the valve train system? Where should I start the process of eliminations?

                                  thanks Lawrence

[D Yaros]

Am not an authority on these things, but would offer the advice of start with the simple and go from there.

 

If the vacuum is fluctuating is there a vacuum leak?

 

You say it misses badly at idle, but drives well.  The miss goes away on acceleration?  Could it be a carb problem, as opposed to a valve/ignition problem? 

 

Just throwing out ideas....

 

[Tedd Thompson]

  Can you hear a leaky swish sound on the miss  at the exhaust pipe? Sounds like it maybe a burnt valve. A compression test would tell if it is and what cylinder. Other than that it could be a multiple of things, wires, plugs carb setting, bad points, vacuum leak, hard to tell from afar. If mine I would do a compression test first it will tell you more than just if a valve is bad but also what shape the internals of the engine is in... Tedd

[lawrence]

Yes Tedd , I do hear a swish in cadence with some lite valve train noise. So I will do a compression test and go from there.

             thank you much for answer my post