I have a 351w with a c4 tranny. The engine idles great "idle set at 950", until you put it in gear, then the idle drops WAY down and it will go dead unless you keep the idle up by keeping your foot on the accel. pedal. I have not been into the engine, but I was told that it has a lunati cam in it, and it has a alum. intake. When I bought the truck the forward frictions in the c4 were burnt up in the tranny, so I completely rebuilt it. I also added a TCI 2500 stall converter. I have checked all over the top of the engine for vacuum leaks and have not found any. I have to set the idle at about 1500 just to keep it running in gear, please help me out, this is about to drive me crazy. BTW this was the first tranny that I have built, it went very smoothly and I learned a lot, but I have to ask, I checked clearance with a feeler gauge during final assembly, if it was put together to "tight" would it cause this problem??
Does it have an edelbrock carb & been sitting a while? take it apart & clean it out. My 51 ford had the same trouble plus it has a 750cfm that I think is too much. Billy
"borrow" a working carb from a friend with a similar engine build and see if this takes care of your problem. This might be a simple way of narrowing things down. Assuming that the stall converter is working right, which since it is new I am sure it is, I am going to say that the tranny is NOT your problem. While there could be a tranny issue, it ain't the root of your problem here. I vote carb first, then an ignition/advance issue. My first thought was a vac leak though.....
just a thought....is the vacuum advance hooked to manifold or ported source? If it is a manifold vacuum source it may be causing a further loss of timing when put in gear causing the RPM to worsen. More info on the engine build could futher help.
Damn, does anyone else have issues editing a post? Seems like my computer gets stuck forever when I try to edit here... So, since my patience is thin, I am just going to post again... If the engine has not been run, or has never run well since build/rebuild, the cam timing may not be set right... ouch...
Did you check your vacuum line that goes to the trans for leaks ?Really hard to know what the problem is but thats a easy place to start .My last 2 cents
Hey, guys I was using a 670 cfm street avenger, I borrowed a friends 650 double pumper, but it still did the same thing. I also unhooked all the vacuum souces and plugged them, still did the same thing. The vacuum advance was hooked to the carb, so I plugged it and locked it out at 32, still did the same thing. The vacuum line going to the tranny is new. The engine just had a crank kit put in it before I bought it, they also put a , as they called it "big" lunati cam, other than that and the alum. intake it is stock. a mechanic put the crank kit and cam in before I bought it. The alum. intake is a old one and it has stripped threads and just looks suspect, should I try replacing it? The engine runs good in park and going down the road, trying to decide if I should pull the engine tear it down and start over, so I will know what I have? Any other suggestions are appreciated.
have had the same problem a few times with old rods i have bought usually is the carb. i rebuilt the carb, new plusgs and wires, check my distributor, check and adjust time, last if old motor and able to adjust valves I do so..........it will perr like a kitten
Well it is safe to say it ain't the carb.... There might be a reason they sold that intake with the engine, might be the same reason that they did not bother to fix the stripped bolts. Yea, a little cynical, but the intake could be warped or cracked. Have you tried spraying carb cleaner around the ports when the engine is running? Might pull the intake and check the gasket sealing areas and do a visual for cracks, and run a straight edge along the mating surfaces... kind of a PITA to do, but not real expensive or a lot of work on most older cars/engines. With older engines, it is pretty much "ignition", "fuel", "timing" Fuel should be right, assuming no intake leaks, move to ignition and timing....
the one other thing to consider is where the vaccum line from the trans is hook up i believe that it needs to be at the manifold, i seem to remeber that makeing a idle differance on my Mustang II with simular setup
Start with the engine idling in Park and check vacuum at the manifold. If rough, it could be cam messing around. I agree with stall speed of converter, and also the carb. Normally you set the idle speed in Dr along with idle mixture. With the cam you have that might be the only way to keep it going. Another thing that might need to be checked is where the modulator is getting it's vacuum, along with checking it for vacuum retention. The vacuum source must be the manifold vacuum, with one exception, Furd used dual port modulators which used both vacuum sources. Fun little critters, made my C4 bang hard when cold through 1-2 shift. Warm engine shifted firm but not as hard.
Yours has to be a vacume prob. My falcon had 305 lift cam w/2500 converter, Ideld 1k in park and 1k in drive due to 2,500 conv. with that conv I had to give it gas to move. Maybe junk conv?
I would check for air leak on the intake, maybe even a crack. Your problem is most likely vacuum leak. If you changed the carb, I would look at the intake and all lines.
I do tend to agree with this comment. I would think a true 2500RPM converter should give little load on the engine at idle. Can you get the cam specs on "the big cam" that was put in? It may be quite a bit bigger than you suspect. If that is the case you may be able to cover up a little of the idle problem with the good ole Rhoads lifters?! But the converter needs to be matched to the cam/engine size/vehicle weight.
If the clutch packs are tight then it might want to drive in neutral, but it will not cause the symptoms you have...which are an engine with no low end torque mixed with a converter that seems to be a bit too tight for it's 2500 stall rating
Well, I am leaning toward, going into the engine and putting a small 268 comp extreme entergy cam in, The rmp range is 1600-5800. So, my converter should work with that cam. Put a new intake manifold on while I have it off, that will put the uneasy feeling about the intake to rest. The intake that is on the car has a lot of stripped threads and I just do not trust it. What do ya'll think?
That is one of my problems, I do not know what size cam it is. The guy that put it in there cannot remember. That is why I am thinking about putting a new one in, so I will know what I have, and I will know it will work with my converter.
Sounds like a good idea. I'd change the valve springs to ones that match the cam, too...and of course new lifters.
Use a holley with the cam they have 4 courner idle adjustment should take care of the problem.start by running them all the way in and back them out 1 1/4 turns if you dont have a vacume gage
Look up Ford transmission forum. These guys know ford trannies and are very helpfull. If you have a high duration cam you will have to increase your idle speed with an automatic. I had a 5.0 motor with a mild cam and a C4 with stock converter. I had to run a higher idle so it wouldn't try to stall at idle. I switched to a T5 trans.which allowed me to reduce the idle speed. Are you sure you have a 2500 stall converter?
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