Car runs great , no flat spots but doesn't have that smooth idle that I would expect from an all stock freshly rebuilt 292. No vacume leaks, all new ignition components, properly adjusted valves and a pertronics ignition, timing & idle speed within spec and the choke cycles properly.

I was expecting an idle like that of a bone stock 289 or 390....don't get me wrong it doesn't sputter or shake your teeth out it just isn't as smooth (especially in gear) as I feel it should be. This is my first Y block and my introduction to the Holley 4000 teapot.... are they bad idlers ?

A vacuum reading on the engine at both idle and fast idle would be the easiest thing to check when trouble shooting.  An erratic reading could point you towards weak or broken valve springs and definitely cause a rough or erratic idle.

I'd suggest performing a leak down test on the engine.  My first thought is the valves aren't sealing tightly. Even if you just had a valve job, if the valves were not hand lapped there's the chance you're getting some leakage at this point and leakage on any intake valves will upset other cylinders.  And my second thought is the carburetor isn't at 100% effieciency.  Teapots are good idlers when they are right but any restricted or stopped up air bleeds can make them as cantankerous as the next carb.

I'm assuming the lash is set to spec and the initial ignition timing is set correctly.  Was the TDC on the damper checked for accuracy when the engine was going back together?  A slipped damper doesn't seem to be that uncommon now that they are going on fifty years old.  Rechecking the valve lash is also suggested and any rockers that suddenly come up loose can be indicative of a cam shaft having lobes going flat among other things.

Lorena, Texas (South of Waco)

Ted:

All you say has merit, except for one thing.  The heading for the post says "55 T-Bird".  Birds do not have the timing marks on the damper ring, but rather on the fixed part of the pulley.  The marks cannot slip.

John 

John - "The Hoosier Hurricane"

Thanks John.   I missed that.

Lorena, Texas (South of Waco)

On the subject of dampners: When the ring on my original 55 Bird unit slipped, I installed a new one made with epoxy-injected technology (don't ask why I turned my back on a proven design that lasted 50 years). It failed one year later. The ring came loose and was slapping the motor mount/front cover. Lucky I didn't break a crank. The manufacturer claimed mine was the only one of his to ever fail. Just my luck! Though they sent a free replacement, I had better things to do than pull the radiator again.



P.S. I have 65K HARD miles on a set of stock 113 service heads/valves/springs. Runs like gangbusters (teapot), but idle is also NOT smooth!

6 VOLTS/POS. GRD. NW INDIANA

Thanks for all of the replys....I will try the vacume gauge this weekend and see what it tells me. But, the valve springs are new and the compression is good and even in all 8 cylinders (I don't have a leakdown tester) , no cam problems as it was fresh 600 miles ago and properly broken in using Rotella oil (high zinc content) and the standard 2000 rpm for 30 minutes cycle. The cam is also holding adjustment with no loose lash on any valves. I did also index the balancer when I put the engine together and the pulley mark was right on.

I am pretty convinced that my problem lies within the teapot. I have the factory supplement manual for the carb and it does notappear to be a very straight forward item to work on. In fact it looks very confusing. I hesitate to take it apart myself and would rather send it out to a qualified teapotoligist. Does anybody know of a good rebuilder ?

I had a local guy with a lot of experience do mine (worked at a Ford dealership back in the 50's). Charge was reasonable (I think he got the kit from NAPA), and it ran OK. Since I wanted a spare, I bought one from PONY (866) 662-3003. It cost an arm & a leg (plated), but they start with a very high-grade core (if the body is warped it can't be saved) and run them in on a test motor. I had to send it back for some fine tuning, but it runs MUCH stronger than my orig. 4000.

6 VOLTS/POS. GRD. NW INDIANA

Pete:

Does the engine actually idle rough, or do you just feel it in the car.  The T-Bird front mount is actually a truck cushion, and rather stiff.  Also, manufacturers try to "tune" engine mounts to keep harmonics from transferring to the chassis.  They do this by the hardness of the mounts and their location on the engine.  To me the T-Bird system is a patched together solution with the truck mount in the front and the steady rods on the sides of the block to keep the engine upright in the compartment.  Chrysler started this tuning business with their "floating power" system in the '30s.

You might try backing the nuts off at the steady rests a little and see if that changes what you feel.  I don't recommend running them loosened, but if that temporarily stops the roughness, at least you will know what it is and not worry about it.

John

John - "The Hoosier Hurricane"

John,

     Correct, it doesn't actually run rough but you can really feel it in the car. If I pop the tranny into neutral at stop lights it is fine but left in gear it can be felt. Your assessment of the mounts is probably correct and is something I hadn't considered before.The fact that they are all new and that I have the steady rests real tight probably doesn't help matters much. Aside from the idle the car runs like a champ... Just to make myself happy I may buy a kit and take a peek inside this winter just to be sure that the ethanol hasn't gummed up any of the passages or send it out.

There is a website "Old car service manual project" that is a GREAT resource for carburator as well as other car related topics. Check it out. Pete