Hi guys. Can the overich exhaust smell be a timing issue?. I have recently installed the Flamethrower coil, Ignitor module was already in the car when I bought it, I re-gapped new spark plugs gaps to .044, My Holley 4160 carb was rebuilt last summer (6.5 power valve). I adjust the mixture screws inward until the car begins sputter and then back it out every so slightly. The cars runs pretty well but the smell is brutal. When I recently changed my plugs, the old plugs were quite sooty. How do you know if a Power Valve is blown? I believe the the timing should be set at

6˚ BTDC. Does changing it slightly make any sense?

Nat,

     Try 10 degrees, but listen carefully for "pinging" Should help. Do you have the exhaust crossover blocked? If so that will cause you to need a slightly richer misture. AND, make sure you have the vacuum blocked off when you set the initial timing.  

Frank/Rebop

Bristol, In ( by Elkhart) 

Hey guys. Thanks for the tips. I may have to leave this up to my mechanic come spring. My carb is an original Holley 4160 double pumper. I believe I read somewhere the spec was 390 CFM.

The 6.5 power valve is the valve that was in there when I bought the car. It ran quite well and the exhaust smell was not that bad. When the carb was rebuilt he put in 7.5 power valve and it really ran rich and adjusting the idle mixture screw did very little, so he put a 6.5 back in. I did have my vacuum reading done and it was 17. I may be over my head here. I will my mechanic check the timing. I think he set it at 6˚ BTDC just after I got the car - I think this is the spec they call for in the shop manual.

Nat:

Read your last post.  The car was OK until the carb was rebuilt, has not been OK since.  If nothing else was done, then don't try to cover up the problem with other changes.  Sort out the carb issue.  Also, I don't think the 390 was a "double pumper".  A double pumper has an accelerator pump on both the primary and secondary fuel bowls, and is usually a mechanical secondary instead of a vacuum secondary carb.

John in Selma, IN

John - "The Hoosier Hurricane"

John's right here. With what you've added, it now sounds like a carb issue, and it's more than a power valve problem.

Frank/Rebop

Bristol, In ( by Elkhart) 

I did some searching on my Carb- The numbers stamped on the air horn (on the left side) 603 Top right: ECZ V Lower right: List 1273 Front metering Block: 1584 Rear metering Block: 1589

Can anyone decipher it and know what carb and CFM. I could not find anything conclusive on the net. I am debating if buying a new Holley carb would be easier and more economical than having it rebuilt a second time ($275.00). As i mentioned before it runs really rich. If i turn the idle mixture screw on the left side to lean it out the car will eventually stall which I believe is normal. If I turn the right side mixture screw inward the car will idle a bit slower and rougher but will keep running. I pulled a spark plug today to check the deposit. It had quite bit of soot and thats with about 75 minutes of run time on brand new plugs. When my carb was rebuilt in the summer fuel gushed out of the sight holes. Apparently the guy who rebuilt said he rebuilt it to Ford / Holley specifications. I was so fed up with this guy I lowered the floats myself - If anything they are a bit on the low side. What NEW Holley carb could anyone recommend that would be closest match to the original carb? I have a 57 Tbird with a 312 and Fordomatic tranny. The Vacuum test I did in the summer showed 17. Car is pretty much stock. I would like to keep it looking as stock as possible. I am not sure what CFM these cars came with stock.



Thanks

Nat:

The ECZ-V carb is for '57 passenger and T-Bird, 312, Fordomatic.  Sounds like the original carb for your car.  It is valuable, I would keep it just because it's the original.  If you ever go for concours judging, or some subsequent owner does, that carb is a must.  Replacements have a different fuel inlet direction, a dead giveaway to a judge.

There are air bleed holes in various places in the carb, and if they are partially restricted because of insufficient cleaning, they can cause rich mixtures.  Inneffective idle screws usually point to a leaky power valve or gasket, but there can be other causes too.  Is the car hard to start after sitting for 10 minutes, and blows black smoke out the pipes when it does start?

John

John - "The Hoosier Hurricane"

Nat,

     I rebuilt one of these for a fella about twenty years ago. Not being familiar with the original Thunderbird Carb, which that is, I reversed the jetting. All modern Holleys have larger secondaries, and smaller primaries. You carb does not, the primaries are larger than the secondaries and require the larger jets be in the primaries. That may or may not be part of the problem. Second, if the floats in the primaries were set incorrectly, then the secondaries are probably also wrong. Third, replace the power valve with a NEW 6.5 as per original and be sure to replace the gasket. Last, make certain your "expert" put the correct gaskets on the metering plates and float bowls, it's simple to mix them up. I'd also get a cat of carb cleaner and check to be sure the idle circuits and air bleeds are open and not blocked. Somewhere in there I think you'll discover the problem.

    I think that the carb is somewhere in the 400 cfm range, most guys who replace them go for something in the 500 cfm range in a newer Holley, Demon or Edelbrock (the old Carter AFB. Pony carbs in  NM can rebuild these. They aren't cheap though. You can google or do a search for both Holley and Pony Carbs on the web.

Frank/Rebop

Bristol, In ( by Elkhart) 

Hey Hoosier. Actually the car starts up quite easily with maybe a bit of black smoke, but not much. However when I first start (when its cold) it I get quite a bit of black carbon coming out of the tailpipes and leaves some thick spots of black powder sooty carbon patches on my driveway. Once the car warms up the sooty exhaust deposits clears up. The nuisance is the choking overich smell and heavy sooty deposits on the spark plugs and eventually it will start to run a bit rough. I do remember before I got the carb re-built the plugs having a grey powdery deposit on them suggesting proper combustion. I was getting about 30 miles more to a tank on an average as well. By the way this car was a concourse quality built car finished in 94. The guy who rebuilt my carb told me whoever re-built the carb last time when to a great deal of expense to have the linkage plated etc. Thus I would like to keep it original.

If there is anything other info I can pass onto the carb re-builder please let me know. I may try someone else. I am in the Toronto Canada area.



Again I thank you.

The power valve gasket being the incorrect one or possibly not seated properly would be an easy item to check.  If when pulling the metering block loose from the main body and finding it wet in the power valve cavity, then look hard at the power valve itself for either a ruptured diaphragm or a faulty pv gasket.

 

Another item to check for is a power valve that is bottoming out in the power valve chamber which in turn is not allowing the metering block gasket to fully seat when being tightened down with the bowl screws.  This can be as a result of a replacement valve that is thicker than the original or gaskets that are too thick or multiple gaskets being stacked on top of each other.  Just putting the metering block up to the main body with the power valve installed and seeing that the metering block is flat against the body without a metering block gasket in place should suffice for this check.

Lorena, Texas (South of Waco)