I just picked up a '55 Thunderbird that was restored a few years back, but has been sitting for the last year or so. Once I got it started, there was a pretty healthy gasoline leak from the pump, no doubt caused by the upstream electric pump. With the electric fuel pump disconnected and a new stock pump in place, it's running again, but it doesn't idle well. New plugs to replace the fouled ones didn't help a lot. I connected a vacuum gauge and it is between 10 and 11 inches hg, which seems awfully low. The timing seems to be advanced well beyond the 6 or 8 degrees that it should be, but retarding it makes it worse. When you rev it, it seems smooth and as powerful as you would expect, with vacuum in the 22-24 range.

The previous owner kept receipts of all the work that had been done, and it looks like a couple shops have tried to resolve similar issues with it. There has been a valve job with the heads resurfaced, new intake gaskets, carb overhaul, Pertronix ignition, etc. Compression is a little low, but consistent at 105 psi or so. The valves were set a little loose, so I reset them at .020 but that seemed to make the vacuum drop an inch or so. There is zero blow-by and no evidence of oil on the plugs, so I think that the rings are good.

Finally, sometimes it will idle as long as you like at 7-800 RPMs and is almost acceptable. Other times, one of the secondary barrels fills with fuel, eventually killing it by flooding. It has the original Holley 4000 teapot carb, which I have no experience with.

Anyway, it strikes me as having a vacuum problem that no one has been able to find as well as a carburetor issue. This is my first Y block, but I wouldn't think that it would be much different than diagnosing any other engine. That said, it's kicking my butt and I'm having to reach out to the experts.

Any help is appreciated.

Thanks,
Bobby

Is it still 6V? If so, the Pertronix may not be putting enough spark to the plugs. I had beau coups trouble with the one I installed. I finally went back to points.

The dampers are know for slipping on the hub, I would set the timing using a vac gauge and not worry about the timing marks. Can't help you much with the t pot but there are others on here that can. Just be patient and someone will jump in with good advice. Best advice I could give is dump the 55 dist and go with a 57 later unit. If you search around here you can find a lot of information on the problems with the pre 57 dist.

Glen Henderson



Freedom is not Free

Letohatchee, AL

Some times the rear top large screw on the carb will not be tight enough and will leak into the back barrels causing the engine to overload and idle rough and stall the engine at times. Try setting the timing at 10 degrees if the damper has not slipped, the 3 to 6 degree recommended by ford didn't work very well and made the engine run a little sluggish. The teapots are bad for leaks if not taken care of but once fixed they run very well.

-Gary Burnette-

Thanks for all the advice. The car is 12V and had the Pertronix installed after the problem was noticed.

Since the last post, I have reran the valves to make sure that they are at .020 and done a compression test. All the cylinders were between 112 and 128. Not high, but I would like to think it's enough to pull more than 9 inches of vacuum. What I keep thinking about is the timing. The marks on the balancer run from TDC to 10 degrees (I think). However, it wants t run at about 2.5 inches past that, which I would estimate about 25-30 degrees. Advancing it from there makes it ping, retarding it to the specified 8 degrees makes it feel very sluggish. When it's at TDC per the balancer, the rotor is pointed right at #1. One of the shops that worked on it pulled the timing cover to verify that timing hadn't jumped. Still, it sure makes me think that the cam is not synced up with the crank like it should be.

Welcome ! Your in for a learning curve, we'll get to the problem don't worry. We may need to find out if your a purist or you don't mind changing a few things like the vacuum operated dissy you have in the 55, going to a later model etc etc.. Its not going to cost you an arm or leg but slowly does it..



"Came too close to dying to stop living now!"

I don't mind changing a couple things to get the car right. What's the point owning it if I can't enjoy it? My experience has been with small block and FE Fords, so the Y block is somewhat new to me. Again, I appreciate the sharing of knowledge and willingness to help.

Bobby

Bobby

With the engine at idle and a vacuum gage hooked up to the MANIFOLD advance the distributor to the MAX VACUUM that you can get. This will tell you if your engine timing is near what it should be. 9 inches of manifold vacuum cannot be right. Vacuum leak or retarted timing. Find out. It does not matter what engine, they are all very similar. Pete

Thanks Pete. with it idling around 800 RPM, I could move the distributor 20+ degrees either way and the vacuum would struggle to get above 11 in hg. Also tried adjusting the air mixture screws for max vacuum, but it didn't make much difference either. The manifold had been resealed by a previous shop trying to solve the same problem. When checking with an unlit propane torch, there was no sign of a leak. I might try to cobble together some type of smoke machine tomorrow to see if anything shows up.

I would like to think that the engine builder lined up the dots on the timing gear instead of what the Y block requires, but with the balancer at TDC, the rockers on #1 are loose and the rotor lines up with #1 on the distributor.

If it is a T-Bird engine with the correct front pulley, the timing marks are on the fixed part of the pulley and cannot slip. Does it have power brakes? If so, try disconnecting the vacuum hose to the the booster and plugging it. Sometimes the diaphragm in the booster leaks vacuum. In addition to what Speedpro said about the large plug on the back of the fuel bowl, there is also a brass transfer tube between the base and the bowl, sealed with O rings. If that leaks, fuel will run into the secondary bores. And speaking of secondaries, are they closing completely? If not, they become a vacuum leak as there is no idle circuit in them. Also, the vacuum hose to the wipers could become a leak, try disconnecting and plugging it.

John - "The Hoosier Hurricane"